Introduction BLEEDING &CLOTTING Hemostasis DISORDERS

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BLEEDING &CLOTTING DISORDERS

Dr. Amrita AggarwalDept. of Oral Medicine and

RadiologyMGDC&H, Jaipur

CONTENTS

1. Introduction

2. Hemostasis

3. Classification

4. Investigations

5. Dental consideration

6. Conclusion

INTRODUCTION

• Hemostasis is the process by which bleeding is arrested after injury to blood vessels by forming a clot

• Functions

– To maintain the blood in the fluid state

– To prevent clots in intact vessels

– To arrest bleeding in the vessels

• Components

– Blood vessels

– Platelets

– Clotting factors

– Fibrinolytic system

NORMAL HEMOSTASIS

• Healthy endothelium prevents the adhesion of platelets by release of NO, prostacyclin and ADP phosphatases.

HEMOSTASIS

• Vascular phase

• Platelet phase

• Coagulative phase

• Fibrinolytic phase

Vascular phase-vasoconstriction

Platelet phase

Platelets adhere to form a primary hemostatic plug

Coagulative phase

Clotting factors gets activated and forms the secondary hemostatic plug. 2 pathways

Fibrinolytic phase – clot disintegration and vessel wall repair

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COAGULATION CASCADE

• Coagulation involves a series of protease reactions

• Conversion of soluble fibrinogen into insoluble fibrin

• Fibrin and platelets together forms the secondary hemostatic plug.

FIBRINOLYTIC CASCADE

• Dissolves fibrin

• Clot dissolution

• Plasminogen is precursor of plasmin which breaks fibrin

CLASSIFICATION OF BLEEDING DISORDERS

• Vascular disorders

• Platelet disorders

• Coagulation disorders

• Combination of the above

Clinical features

DIFFERENCE BETWEEN BLEEDING AND CLOTTING DISORDERS

Bleeding disorders Clotting disorders

Platelet and vascular Clotting factors

Bleeding from superficial cuts persistent and profuse Minimal

Spontaneous gingival bleeding Characteristic Rare

Petechiae Characteristic Rare

Ecchymosis Usually small and multiple Usually large and single

Epistaxis Common Common

Hemarthroses Rare Charateristic

Deep dissecting hematoma Rare Characteristic

Torniquet test Positive Negative

Applying pressure May stop bleeding Bleeding reoccurs

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LAB INVESTIGATIONS

Platelet function

• Platelet count

• Bleeding time

• Platelet aggregation test

• Platelet adhesion test

• Capillary fragile test for vascular function

Blood coagulation

• Clotting time

• Prrothrombin time

• Activated partial thromboplatin time

• Fibrinogen levels

• Fibrin degradation products

• Coagulation factors assay

BLEEDING TIME

• Time required for a standardised wound to stop bleeding

• Used to check functions of platelets and capillaries

• Normal – 1 to 6 min (modified ivy’s method)

• Increased in

– Thrombocytopenia

– Von willebrand disease

– Vascular abnormalities

– DIC

CLOTTING TIME

• Time required a sample of blood to coagulate invitro

• Normal – 1to 8 minutes

• Increased in haemophilia

PROTHROMBIN TIME & INR

• Normal PT 11 to 13 sec

• INR is introduced by WHO in 1983

• Calculation made to standardise prothrombin time

• Ratio of PT that adjusts for the sensitivity of the thromboplastin reagents, such that a normal coagulation profile is reported as an INR of 1.0.

• evaluates the extrinsic coagulation system and measures the presence or absence of clotting Fs I, II, V, VII, and X.

• used to measure the effects of coumarin anticoagulants and reduction of the vitamin K–dependent Fs II, VII, IX, and X.

INR – PATIENT PT/ *ISICONTROL PT

INR ratio

1 Ideal

2 to 3 Therapeutic range of coumadin

Below 2 Associated with minimal bleeding

3 to 4.5 Associated with severe bleeding

ACTIVATED PARTIAL THROMBOPLASTIN TIME

• Evaluate the intrinsic pathway and common pathway

• It measures the time (in seconds) needed for the plasma to clot after the addition of kaolin, cephalin, and Ca2+.

• Normal APTT is 15 to 35 sec

• prolonged only when the factor levels in the intrinsic and common pathways are less than about 30%.

• It is altered in hemophilias A and B and with the use of the anticoagulant heparin

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THROMBIN TIME • The TT is used specifically to test the ability to form the initial clot

from fibrinogen and is considered normal in the range of 9 to 13 seconds.

• Additionally, it is used to measure the presence of heparin

FIBRIN DEGRADATION PRODUCT ASSAY

• FDPs are measured using a specific latex agglutination system to evaluate the presence of the D dimer of fibrinogen and/or fibrin above normal levels.

• Such presence indicates that intravascular lysis has taken place or is occurring

VESSEL WALL DISORDERSSCURVY

• Dietary deficiency of watersoluble vit C below 10mg/dl

• Defect in collagen synthesis

• petechial hemorrhages at the hair follicles and purpura on the back of the lower extremities that coalesce to form ecchymoses.

• Hemorrhage can occur in the muscles, joints, nail beds, and gingival tissues.

• Gingival involvement may include swelling, friability, bleeding, secondary infection, and looseningof teeth.

• Implementation of a diet rich in vitamin C and

• administration of 1 g/d of vitamin C supplements provides rapid resolution.

CUSHING’S SYNDROME • Excessive corticosteroid production or intake

• General protein wasting and atrophy of surrounding connective tissue

• Skin bleeding and easy bruising

EHLERS – DANLOS SYNDROME

• Inherited disorder of connective tissue matrix

• Fragile skin, easy bruising, hyperelasticity of skin and hypermobility of joints

RENDU – OSLER – WEBER SYNDROME

• Hereditary hemorrhagic telangiectasia, autosomal dominant disorders

• Abnormal telangiectatic capillaries, frequent episodes of nasal and gastrointestinal bleeding, and associated brain and pulmonary lesions.

• Common on lips, tongue, palate

• Treatment - cryotherapy, laser ablation, electrocoagulation, or resection.

PALETLET DISORDERS THROMBOCYTOPENIA

• Reduced platelet count

– decreased production in the bone marrow

– increased sequestration in the spleen

– accelerated destruction.

CONGENITAL PLATELET DISORDERS

• Hereditary thrombocytopenia

– May-Hegglin anomaly

– Wiskott-Aldrich syndrome

– Neonatal alloimmune thrombocytopenia

• Platelet function defect/ glycoprotein defect

– Glanzmann’s thrombasthenia ( GPIIb & GPIIIa)

– Platelet-type von Willebrand’s disease

– Bernard-Soulier syndrome( GPIb)

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ACQUIRED PLATELET DISORDER

• Immune or idiopathic thrombocytopenic purpura

– Autoantibodies against own platelet antigens

– Acute – selflimiting and common in children

– Chronic – indolent and in adults

• Thrombotic thrombocytopenic purpura

– metastatic malignancy, pregnancy, mitomycin C, and high-dose chemotherapy

– Hemolytic uremic syndrome - Microangiopathic hemolytic anemia, fluctuating neurologic abnormalities, renal dysfunction, and occasional fever.

COAGULATION DISORDERS

• Hemophilia A

– Deficiency of factor VIII(antihemophillic factor)

– X-linked recessive disorder

– Types –mild ( <4% AHF)

moderate (1to 4 % AHF)

moderate to severe (0.0 to 0.9% AHF)

severe (0.0% AHF)

– Signs – easy bruising, hemoarthoses, GI bleeding, hematuria, spontaneous gingival bleeding

CHRISTMAS DISEASE• Deficiency of factor IX

• X- linked recessive trait

VON-WILLEBRAND DISEASE

• Defect in von-willebrand factor (F VIII protein complex)

• Autosomal dominant triat

• Menorrhagia, easy bruising, mucosal bleeding, gingival bleeding, epistaxis, GI bleeding, postpartum bleeding, bleeding after surgery or dental extraction.

DISSEAMINATED INTRAVASCULAR COAGULATION

• Syndrome in which systemic activation of the coagulation leads to consumption of coagulation factors and platelets

• Can be dominated by bleeding, vascular occlusion and tissue hypoxemia, or both

• Common triggers: sepsis, major trauma, certain cancers,obstetric complications

MANAGEMENT

• prevention of hemorrhagic episodes,

• prompt control of bleeding when it occurs

• management of the sequelae of the disease and its therapy.

MANAGEMENT

• Platelet disorders

– Transfusion of platelets below 10,000

– Corticosteroids for ITP and splenectomy

– Bone marrow transplantation

• Hemophilia

– Depends upon the severity of the disease

– Factor replacement

– Commercially prepared Fs VIII and IXcomplex concentrates, desmopressinacetate, cryoprecipitate and FFP are replacement options

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DENTAL CONSIDERATIONS

• Low risk

– No history of bleeding

– Normal laboratory values

• Moderate risk

– Patients under anticoagulants, aspirin drugs

– With INR between 2 to 3

• High risk

– History of bleeding tendency

– Abnormal laboratory values

BLEEDING DISORDERS

Platelet count Dental treatment

1 >75,000 Normal protocol

2 40,000 – 75,000 Platelet transfusion may be considered

preoperatively and post operatively

3 < 40,000 Avoid invasive dental treatment, in

dental emergency supportive measures

should be considered

PAIN MANAGEMENT

• NSAIDs – avoided as it increases bleeding tendency and safest is paracetamol

• Nerve block anesthesia is contraindicated , increased risk of hematoma formation

• Anesthetic infiltration and intraligamentary anesthesia

• Anesthetic with a vasoconstrictor should be used when possible

ORAL SURGERY

• High risk of bleeding where safety precautions are necessary

• transfusion of appropriate factors to 50% to 100% of normal levels is recommended

• Local hemostatic agents and techniques such as pressure, surgical packs, sutures and surgical stents may be used individually or in combination.

PERIODONTAL TREATMENT

• Scaling depends on the severity of the probing depths and the patient’s level of oral hygiene.

• Supragingival scaling with local hemostatic measures (eg, tranexamic acid) is considered safe

• Ultrasonic scaling results in less tissue trauma

RESTORATIVE & PROSTHETIC TREATMENT

• Can be safely done provided protection of oral mucosa

• Rubberdam placement and suction tips should be used cautiously

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PATIENTS ON ANTICOAGULANTS

• Dental procedures are planned based on INR values and level of thromboembolic risk.

• INR >3.5 to 4 – no surgical treatment with Coumadin dose modification

• INR <3.5 to 4 – minor surgical procedures with expected minimal bleeding by local measures without modifying Coumadin dose

• INR <3.5 to 4 – multiple extractions with moderate bleeding, local measures used along with reduction of INR

• INR <2 to 3 – significant bleeding expected , local measures

• INR < 1.5 – extensive flap surgery ,multiple bony extractions

CONCLUSION

• Patients with bleeding disorders should be evaluated carefully

• Patients with mild bleeding disorders can be treated in a primary care setting after consultation with the hematologist.

• patients with a moderate to severe level of bleeding disorder who require invasive dental procedures are best treated in a hospital setting.

THANK YOU

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Dr. Amrita Aggarwal

Dept. of Oral Medicine and Radiology

MGDC&H, Jaipur

Is defined as a planned professional

conversation, which enables the patient

to communicate the symptoms, feelings

and fears to the clinician, so that the

nature of the real and suspected illness

and mental attitude may be determined

(REFERENCE- Oral Diagnosis,medicine &treatment planning-

Bricker/langlais/Miller 2ND EDN)

History is a personal account of patient’s

problem. It is the most important

component of clinical diagnosis. The

main aim of history taking is to elicit an

accurate account of the symptoms and of

clinical problems as a whole and to set

this against the background of patient’s

life.

TYPE OF CASE

HISTORY

COMPREHENSIVE ABBREVIATED

It Contains

Patient’s history

Clinical examination

Radiographic and supplemental

examinations

Diagnostic Summary

Treatment planning recommendations

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1.SCREENING AND RECALL EVALUATION Consist of: 1. An abbreviated history 2.An abbreviated clinical examination 3.Selected Radiographic and adjunctive tests 4.A Diagnosis 5.Treatment recommendations. 2.EMERGENCY EVALUATION 1.An abbreviated histiory 2.Superficial clinical examination 3.Selected Radoigraphs 4.Diagnosis 5.Treatment planning

1)comupter allied data gathering

2)Russel’s “condition diagram”

Cd method

Weeds Problem Oriented Method(POR)PMID: 2337438 [PubMed - indexed for MEDLINE]

PATIENT INTERVIEW

The dentist can ask two general types of

questions when interviewing:

Open

Closed

OPEN QUESTIONS: Open questions cannot be answered with a

simple response,such as “yes” or “no” Instead they involves patient by asking the

opinions,past experiences,feelings,or desires. It usually begin with “what” and “how” and

should avoid leading the patient to a specific answer

Examples:How can I help you?What do you think is your biggest dental

problem?Tell me about your past dental problem?Tell me about your past dental care

CLOSED QUESTIONSOn the other hand,close questions are

usually simple to answer with one or two words.

They permit dentist to obtain specific facts or classified but they do not provide insight into patient beliefs,attitudes,or feelings.

Eg:Do any of your teeth hurts?Which tooth is sensitive to cold?How long has it been since your teeth were

last examined?

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To establish a positive professional

relationship

To provide the dentist with information

concerning the patient past and present

medical,dental & personnel history

To provide the dentist with information that

may be necessary for making a diagnosis.

To provide information that aids the dentist

in making decision concerning treatment

1.Demograhic data

2.Chief complaint and its history

3.History of present illness

4.Past medical history

5.Past dental history

6.Personal history

7.Family history

8.Emotional and behavioral history

9.Examination-Extraoral-Intraoral-Examination of soft tissue

-Examination of hard tissue 10.Summary 11.Provisional diagnosis 12.Differential diagnosis 13. Investigation 14.Final diagnosis 15.Treatment planning 16.Prognosis

1.Name

2.Age

3.Gender

4.Address

5.Occupation

6.Registration Number

7.Contact Number.

Useful for-1)Identification

2)Communication

3)Forming a rapport with

patient.

4)Psychological effect

5)Information of the patient

such as religion

Useful for –Diagnosis

Treatment planning

Behaviour management

CHRONOLOGY

To know the chronology and co relate the

dental age with chronology age

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YOUNG RULE- Child’s age x adult dose

Age +12

CLARK RULE-child age at next b’day x

adult dose

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DILLING RULE-Age x adult dose

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A. PREDILECTION OF DISEASECertain diseases are common since/at birth Agnathia Facial hemihypertrophy Macrognathia/micrognathia Cleft lip/cleft lip Fissured tongue AplasiaDISEASES MORE COMMON IN CHILDREN AND YOUNG

ADULTS Focal epithelial hyperplasia Papilloma Thyroglossal duct cyst Basal cell Carcinoma Burkett’s lymphoma

DISEASES PRESENT IN INFANCY

Palatal cyst of new born

Haemangioma

Fibrosarcoma

Thalassemia

Herpe’s syndrome

DISEASES COMMON IN OLDER PATIENTS

Attrision/Abrasion

Gingival recession

Periodontitis

Leukoplakia/lichen planus

Cementicles/fibroma

Ameloblastoma

DISEASES COMMON IN FEMALES .recurrent apthous stomatitisCentral cementifying fibroma Juvenile periodontitisTorus palatinusDISEASES COMMON IN MALES1. Attrision2. Leukoplakia3. Carcinoma in situ4. Benign osteoblastoma5. Ameloblastoma fibroma6. Keratoacanthoma

B.DOSE:Females have smaller body

weight and requires lower dose as

compared to males

In females consideration in dose is given

during mensturation ,pregnancy,lactation

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Drugs given during pregnancy can affect

foetus.

C.Treatment Planning depends on

Gender

Females:Cosmetic importance

Males:Functional importance

1)To maintain contact with the patient.2)Certain diseases are common in certain

area.Endemic diseases/geographic prevalence of certain diseases.for eg.

In India-cancer of tongue &buccal mucosa-more common

In Mumbai,common site affected in cancer is tongue In chennai-Buccal Mucosa Fluorosis in orissa Dental caries- more common in modern

industralized areas.while periodontal diseases are more common in rural areas

Gutka in north india(Bihar) Chutta,a form of tobacco in Tamil naidu

To know about the financial status of patient since the treatment depends accordingly and certain diseases are occupation related. Foreg

Attrision:workers in industeries exposed to substances like asbestos, coal products,cottondust,wood dust,welding fumes.

Abrasion:Shoe maker,carpenter,tailor who hold nails,pins

Hepatitis B-dentist,Surgeon Dry Eye Syndrome-Software professionals Gingival Stains:Person working with

lead,bismuth&Cadmium get strange dark stippling of the marginal gingiva.

It is good to give each & every patient a

unique registration number & to maintain

his/her record under that number . So

that when the patient visit the doctor at

the later date, the doctor can know the

detail of the patient & the treatment done

before

Patient/Physician contact number, recall It is established by asking the patient to

describe the problem for which she or he

is seeking help or treatment. It is

recorded in patients own words

Significance :Pt. knows better about his

disease

We may underestimate or overestimate

the disease

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Patient may or may reveal a detailed history of the problem for which they are seeking treatment and additional information usually needs to be elicited by the examiner. The patient response to these questions may constitute the history of present illness

It is elaboration of patients chief complaint when & how it began,what exacerbates & what ameliorates the complaint.

When and how the complaint has been treated and what was the result of any such treatment and what diagnostic tests have been performed.

Direct and specific questions are used to elicit this information.

When did this problem start?What did they notice first?Did you have any problems or symptoms

related to this?What makes the problem worse or better?Have the symptoms gotten worse or better

at any time?Have you consulted other dentists,

physician?What have you done to treat these

symptoms

IntensityQualityLocationOnsetAssociated events at onsetDuration and timing of painCourse of symptoms since onsetActivities or experience that increses painActivities or experience that decrease painAssociated symptoms(eg,altered

sensation,swelling)Previous treatments and their effects

INTENSITY-sharp,piercing &lancinating or dull, gnawing &excruciating

QUALITYdiffused or localized,LOCATIONMODE OF ONSETsudden or gradual,TYPES OF PAIN-

intermittent,recurrent,constant or referred Associated events with onset,duration and

timing of pain.Altered sensation,swelling or previous treatment and their effects.

1)Duration & mode of onset.

2)Pain & progress of the swelling

3)Other Symptoms associated the lump.

Some negative answers are more

valuable in arriving at diagnosis and

should never be disregarded.

SERIOUS / SIGNIFICANT ILLNESS- -About any heart,lung or kidney diseases Congenital conditions Infectious diseases Immunological disorders Diabetes or hormonal problems Radiation or cancer chemotherapy Blood disperasias or bleeding disorders2.HOSPITALISATION: Hospital records are often the dentist best source of accurate

documentation of the nature and severity of the patients medical problem

3.TRANSFUSION: History of blood transfusion including the date of each transfusion,

no. of transfused blood units,may indicate previous history in the evaluation of the patient medical status

4.Allergies

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Medication:It is imp. to record all the medicines patient is taking.

Ask for their dosage, duration & composition. It helps in recognition of drug

induced(iatrogenic) disease and oral disorders a/w different medication and in avoidance of untoward drug interactions.

PREGNANCY: Knowing whether or not a woman of child

bearing age is pregnant is particularly important when deciding to administer or prescribe any medication

This includes: Place of residence (with family,alone, or in an

institution), marital status(marrried,

separated,divorced,single) Educational level Habits-oral hygiene

delitorious habitsoral habits-1) Thumb sucking2) Tongue thrusting-3) Mouth breathing-4) Bruxism- 5) Other habits

Serious medical problems in immediate

family members should be listed.

Cardiovascular diseases including

hypertension,diabetes,bleeding

disorders,allergies,asthma,

. Some disorders are genetic in the family

should be enquired.

GAIT

TYPES OF GAIT-

1)HEMIPLEGIC OR CIRCUMDUCTION

GAIT

2)SPASTIC GAIT

3)ATAXIC GAIT

4)PARKINSONIAN GAIT

5)SLAPPING GAIT

Stature refers to height and

build,whereas nutritonal status is an

evaluation of the degree of obesity or

emaciation .

Simple recording of height and weight

help in evaluating the nutritional status

Aesthetic-thin physique

-Usually posses narrow dental

arches

Pletoric –person who are obese

-Have large square dental arches

Atheletic-Normally built being neither

thin nor obese

-Have normal sized dental arches

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1. Blood pressure

2.Pulse rate

3.Resp.rate

4.oral temperature

Normal range-120/80mmHg Hypertensive-Systolic Diastolic Stage 1 140-149 90-90 Stage 2 160-179 100-109 Stage 3 >180 >110 HIGH B.P-Causes RENAL DISEASES- Renal vascular diseases ENDOCRINE DISEASES-hyperparathyroidism

- Thyrotoxicosis- Primary hypothyroidism-Cushing syndrome

Blood pressure recording technique

includes

placement of cuff,

SUPPORT ARM AT THE level of heart

palpation of radial artery

and placement of

stethoscope,disappearance of sounds to

measure diastolic B.P.. Take two

measurements at each visit.

LOW B.P.-Causes

- Severe aortic stenosis

-Hypertrophic

obst.cardiomyopathy

-Arrhythmia

NORMAL PULSE RATES

INFANTS AT BIRTH -140bpm

1 yr age -90 to170bpm

AGE 1-2yr -90 to 140bpm


AGE 6-12 -75 to 105bpm


2.PULSE RATE:Pulse rate can be taken as the dentist palpates the radial artery for the blood pressure reading.

When taking the pulse,the examiner should use the fingertips rather the thumb.

The pulse rate is recorded in beats per minute and the normal value is 72.

Pulse rate-Bradycardia <60bpm -Normal 60-100bpm -Tachycardia >100bpm

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NORMAL PULSE RATES





AGE 6-12 -75 to 105bpm


3. RESPIRATORY RATE: The rate of respiration is the number of inspirations recorded

during 1 minute. Respiration is usually rhythmic but not always regular. The rate should be counted by watching the patient’s chest rise

and fall. The normal rate for an adult is approximately 14 to 18 per minute. The normal respiration has regular rhythum with inspiration

longer than expiration. Irregular respiration may be of the following types: A.cheyne-stokes respiration B.kussmaul’s respiration C.Biot’s respiration D.Stridor E.Wheezing.

Normal breathing in males and some females is abdominothoracic i.e both the abdomen and thorax are moving during the act of respiration but the abdominal movements are more prominent.

Normal breathing in majority of females is thoracoabdominal i.e the thoraic movements are more prominent than abdominal movements:

1.Thoracic breathing:thoracic movements are predominant and abdominal movements are minimal.

Occurs in- diaphragmatic paralysis,peritonitis -severe ascites 2.Abdominal breathing:abdominal movements are

predominant and thoracic movements are minimal. Occurs in: Pleurisy Collapse of the lung.

Oral temp.-98.6F/37.0C

Axillary-97.6F/36.3C

Rectal-99.6F/37.7C

Aural-99.6F/37.7C

TEMPERATURE: Patient oral temperature should be recorded.This

is accomplished using an oral thermometer Normal oral temp. is 98.6 F +/- 0.5. Infection,Inflamation. Common cause of elevated temperature; a

hypermetabolic state such as hyperthyroidism can also elevate the patient’s temp.

Hypothermia /decrease in temp. can be associated with a hypometabolic state such as myxedema.

UPPER EXTREMITIES:SKIN

HAIR

FINGERNAILS

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SKIN: The skin is examined by observation and palpation. Color,texture,elasticity,and presence or absence of

edema should be noted. The pigmentation varies in each individual and in

diff.areas like elbows,nuckles,creases and palm of hands.

The texture of skin is evaluated by light palpation.Edematous tissue doesnot usually rebound when depressed with a finger and normal skin does

Bluish pigmentation - seen in bruising,cyanosis Yellow- in jaundice Red - in vascular lesions

Fingernails can reveal indications of systemic disease,the changes found are not pathognomic for specific diseases.

The nail is composed of the cuticle,the nail bed or matrix,a pale semicular configuration at the base of the matrix called the lanula,and the nail itself.

The angle of the nail to the skin should not exceed 160DEG. This is called LOVIBOND’S ANGLE . And it determines whether a nail is clubbed.

CLUBBING-due to overgrowth of nail bed in which levibond angle >160 or almost straight

In clubbing:nails are curved like a watch glass and the finger tip is

bulbous and enlarged.Its causes include

Pulmonary causes-like lung abscess

-Bronchiectasis

Tuberculosis with sec. infections

In koilonychia:nails have a spoon shape and are concave.

-seen in Iron def. anaemia

Pallor of nails:may indicate presence of several conditions.

Specific diseases of nails-

Onychomycosis –fungal infection of nail

Onycholysis-keratin deposition beneath nail bed

-Occurs in psoriasis

HAIRS:

The hair should be evaluated for the

pattern of distribution,color,and

texture.Dry and brittle hair may be due

to hypothyroidism.

In hyperthyroidism –hair texture is fine

In hypothyroidism-amount of hair

decreases.

PALLOR:Pallor of the skin seen in- Massive haemorrhage, shock & intense emotions.Anaemic patients are also pale.One should look at- the lower palpebral conjuctiva mucous membrane of the lips and cheeks, nail beds palmar creases .

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CYANOSIS:bluish or purplish tinge of

the skin or mucous membrane which

results from the p/o excessive amount of

reduced Hb in the underlying blood

vessels.

Types-Central

-Peripheral

CENTRAL CYANOSIS: Occurs due to inadequate oxygenation of blood to the

lungs. Causes- Cardiac causes like-congenital abnormalities of heart - Cong.cardiac failure & cong.cyanotic

heart diseases. Pulmonary causes- -like chronic obst. lung diseases -Pulmonary obstruction -High altitude due to low pressure of oxygen. SITES: Tongue Tip of nose Nail bed Skin of palm & toes

PERIPHERAL CYANOSIS: It is due to excessive reduction of oxyHb in

the capillaries when the blood flow is slowed down. This happens on exposure to cold (cold induced vasoconstriction).

Peripheral cyanosis is looked for in the nail bed, tip of the nose, skin of the palm toes.

ICTERUS : In JAUNDICE- there is icteric tint of the skin due to

presence of bilirubin which varies from faint yellow of viral hepatitis to dark olive greenish yellow of obstructive jaundice. The places where one should look for jaundice are:

1. sclera of the eyeball- for this the patient is asked to look at his feet while the surgeon keeps the palpebral fissure wide open by pulling up the eyelid.

2. nail bed, 3. lobule of the ear, 4. tip of the nose, 5. under surface of the tongue.

HEAD, FACE AND NECK: Important components include an evaluation of the skin, hair, eyes and ears where structural abnormalities may be related to certain acquired disorders or developmental conditions.

SKIN: Examination of skin often gives important clues to local and systemic diseases. The following are noted in skin:

1. Color of skin: like pale flushed, cyanosed, yellow etc." 2. Pigmentation: occurs in certain diseases like Addison’s

disease, Cushing’s disease, pellagra 3. Any hemorrhagic spots like petechiae, purpura,

ecchymosis etc

Lymph nodes are palpated to check the following a. Tenderness of the nodes: The palpable nodes are

tender in acute inflammation . b. Surface of the nodes: Normally it is smooth. Matted

in tuberculosis, irregular in malignancy and inflammation. c. Consistency of the nodes: Normally firm. It is

rubbery in Hodgkin's disease, matted in tuberculosis, hard in malignancy. d. Mobility: Normally are mobile and free from the

skin. In malignancy they are fixed and non-mobile.

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Mesofacial

Dolicofacial

Brachyfacial

1. Mesocephalic: Average

2. Dolicocephalic: Long and narrow

3. Brachycephalic: Broad and short

Facial symmetry is examined to determine disproportion of face in

transverse and vertical planes. Some degree of asymmetry is common

between right and left sides but gross symmetry should be recorded

which may occur as a result of: i) Congenital defects ii) Hemifacial atrophy/hypertrophy iii) Unilateral condylar ankylosis and

hyperplasia iv) Facial space infections.

Round/Oval/Square

i) Mesoproscopic:average or normal

face form

ii) Euryproscopic: broad and short

iii) Leptoproscopic: long and narrow

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Called as "poor man's Cephalometric analysis". The facial profile is examined by viewing the patient from the

side. The profile is obtained by joining the following two reference lines:

A line joining the forehead and the soft tissue point A (deepest point in curvature of upper lip)

A line joining point A and the soft tissue pogonion ( most anterior point of the chin)

i) Straight profile: the two lines form a nearly straight line ii) Convex profile: the two lines form an angle with the

concavity facing the tissue. This kind of profile occurs as a result of a

prognathic maxilla or a retrognathic mandible as seen in class II, Division I malocclusion iii) Concave profile: the two reference lines form an angle with the

convexity towards the tissue. This type of profile is associated with a prognathic mandible or a retrognathic maxilla as in class III malocclusion.

Is defined as an anterior or posterior inclination of the lower face relative to the forehead.

Anterior Divergence: a line drawn between the forehead and chin is inclined anteriorly towards the chin.

Posterior Divergence: a line drawn between the forehead and chin is inclined posteriorly towards the chin.

Straight or Orthognatic: the line between the forehead and chin is straight or perpendicular to the floor

A well proportioned face can be divided

into three equal vertical 3rds using

four horizontal planes

At the level of hair line

At the supra orbital ridge

Base of the nose

Inferior border of chin

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14

Lips should be evaluated for color, texture, fullness, relative length, position during rest and swallowing, and evidence of trauma or pathologic lesions.Lips are classified into the following 4 types:a. Competent lips: Slight contact in relaxed stateb. Incompetent lips: Short lip which do not form

lip seal in relaxed state.c. Potentially incompetent lips: are normal lips

that fail to form a lip sealdue to proclined upper anteriors

d. Everted lips: are hypertrophied lips with weak muscular tonicity.

One should evaluate temporomandibularjoint function by palpating the head of each mandibular condylar and observing the patient while the mouth is closed (teeth clenched), at rest, and in various open positions. Movements of the condyles or jaw that are not smoothly flowing or deviate from the expected norm should be noted. Similarly, any crepitus that may be heard or identified by palpation or any other abnormal sounds should be noted.

Pain in or in front of the ear is a common reason for a patient to seek treatment. A tenderness to palpation implies inflammation, generally as a result of acute or chronic trauma.

A finger should be placed in the immediate pre-auricular area, gently applying pressure on the lateral pole/head of the condial while the jaw is closed. The level of pain and discomfort on each side should be assessed and compared.

The little finger should also be placed in the external auditory meatus, and pressure gently applied forwards.

Agerberg G

Swed Dent J

1974 67:81-86

There are 2 types of joint sound to look

out for:

Clicks - single explosive noise

Crepitus - continuos 'grating' noise

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15

Clicks A joint click probably represents the sudden

distraction of 2 wet surfaces, symptomatic of some kind of disc displacement. The diagnosis of a joint click, and therefore treatment, varies on whether the click is left, right or bilateral, painful or painless, consistent or intermittent. The timing of a click is also significant: a click heard later in the opening cycle may represent a greater degree of disc displacement.

Clicks may frequently be felt as well as heard, though they are not normally painful.

CrepitusCrepitus is the continuous noise during

movement of the joint, caused by the articulatory surfaces of the joint being worn. This occurs most commonly in patients with degenerative joint disease.

The joint sounds should be listened to with a stethoscope, preferably a stereo one, as the two sides can be more easily compared.

This is the only truly measurable parameter, as the others are more subjective. It is just as important to record jaw movement as a means to assess the rate and degree of improvement as it is to determine the severity of symptoms.

Movements to be measured are: Incisal opening - pain free limit Incisal opening - maximum (forced)Lateral mandibular excursionsMandible deviations on pathway of opening

The incisal opening is measured from the upper incisal tip to the lower, with the patient first of all opening to the limit of their comfortable, pain free range. This is then compared to the normal range of motion. Their maximum (forced) limit is also recorded. It is important to determine whether a limitation of vertical movement is due to pain or a physical obstruction. If it is pain, then it may be a muscular problem, if an obstruction, then disc displacement is most likely.

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16

Normal Range of motion

Vertical>40 mm Male

>35 mm Female

Lateral>8 mm Both sexes

Agerberg G

Swed Dent J

1974 67:81-86

The lateral movement should be

measured from mid-line to mid-line, the

patient moving the mandible to their

maximum extent, from one side to the

other

When the jaw is opened, the path it

follows should of course be straight and

consistent. Deviations from the norm are

either lasting or transient, and are all

suggestive of internal derangements of

different sorts.

Lasting deviations are caused by the joint on one side not moving as far as on the other. If the movement is consistent but off centre(i.e. a straight diagonal pathway), this may due to adhesions within the joint. If the movement is normal till just before the maximum range, when a lateral deviation occurs, this may be due to anterior disc displacement without reduction (if the overall range of opening is reduced).

Transient deviations occur when the

joints are moving as far but at different

rates. This is often caused by disc

displacement with reduction.

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17

Oral Medicine diagnosis and treatment-Burket’s (10th Edition) Oral Diagnosis,medicine &treatment planning-

Bricker/langlais/Miller (2nd Edition) Treatment Planning in Dentistry-Stefanac Nesbit Clinical Medicine-Davidson Clinical Manual-Hutchison Textbook of oral pathology-Shafers Textbook of orthodontic-Balaji

.

1

GENERAL, PHYSICAL AND EXTRAORAL EXAMINATION

Dr. Amrita Aggarwal


MGDC&H, Jaipur

CLINICAL EXAMINATION

• General, physical examination

• Extra oral examination

• Intra oral examination

Oral Diagnosis,oral Medicine,and Treatment Planning 2nd Edition Bricker,langlaise,miller

“THE CLINICAL INFORMATION IS PART OF THE PROCESS OF GATHERING INFORMATION SO A DIAGNOSIS CAN BE MADE.”


EXTRAORAL CLINICAL EXAMINATION

General appraisal of the patient

Examination of the head

Examination of the neck

Neurologic examination


GENERAL APPRAISAL OF THE PATIENT

Objective of this part to obtain a general idea of the patient’s Physical status.

Hutchison’s Clinical Methods 21st Edition

• THE MENTAL AND EMOTIONAL STATE

• THE PHYSICAL ATTITUDE

• STATURE AND NUTRITIONAL STATUS

• GAIT AND POSTURE

• UPPER EXTREMITIES

• VITAL SIGNS


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2

THE MENTAL AND EMOTIONAL STATE

• To make some initial assessment of the patient’s intelligence, mental and emotional state.

• Vocabulary and command of language are generally a good guide to know the state.


FOR EXAMPLE:

➢ IF THE PATIENT IS ANXIOUS?

• RESTLESSNESS

• SWEATING PALMS

• DEPRESSION

• LOWERED MOOD

• INABILITY TO MAKE DECISIONS

• MENTAL RETARDATION

• APATHY


(la belle indifference)

Severe disability, without appropriate concern or

anxiety ,suggest a non-organic disorder , or even hysteria.


THE PHYSICAL ATTITUDE

• The patient’s posture may give valuable information.

• Severely ill patient slip down the chair or bed into uncomfortable attitudes.

• Patients with heart failure sit up because they may become dyspnoeic if they lie flat.(orthopnea)


• Patients with colic are restless.

• People with painful joint diseases often have an attitude of helplessness.

• In case of meningitis the neck may be bent backwards so that the head appears to bore into the pillow.


STATURE AND NUTRITIONAL STATUS

• Stature -refers to height and build.

• Nutritional status – refers to an evaluation of the degree of obesity or emaciation.

• simple recordings of height and weight help in evaluating the nutritional status.


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3

Ideal weights for men aged 25 and over

Hutchison’s Clinical Methods 21st Edition Hutchison’s Clinical Methods 21st Edition

WHEN EVALUATING A OVERWEIGHT PATIENT?

• Important To Determine 2 Things:-

PRESENCE OF EDEMA

ACCUMULATION OF FAT


• Edema can be differentiated from fat by depressing the area with a finger.

• Edematous tissue maintain the imprint after removal.

• This is called “pitting” edema

• Fatty tissue rebounds when pressed.

Clinical Medicine Dr. Srivastava 1998

GAIT AND POSTURE

• Gait refers to the way one walks.


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4

• Certain disorder can alter gait and may influence the diagnosis or the treatment plan.

• Patient with a tentative, cautious gait may require management different from energetic and confident stride.


• GAIT

TYPES OF GAIT-

1)HEMIPLEGIC OR CIRCUMDUCTION GAIT

2)SPASTIC GAIT

3)ATAXIC GAIT

4)PARKINSONIAN GAIT

A Manual On Clinical Surgery S Das. 6th Edition

HEMIPLEGIC OR CIRCUMDUCTION GAIT

SPASTIC GAITATAXIC GAIT PARKINSONIAN GAIT

POSTURE:

• Posture refers to the position of the body.

• Is the patients body stooped forward?


Does the head tilt to one side?


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5

BODY BUILT

Aesthetic-

-Thin physique.

-Usually posses narrow dental arches.

Plethoric –-Person who are obese. -Have large square dental arches.

Athletic--Normally built being neither thin nor obese.-Have normal sized dental arches.

Orthodontics The Art And Science 5th Edition S.I Bhalajhi

UPPER EXTREMITIES

• Changes in upper extremities can give indications of the patient’s systemic health.

• Limited to visual inspection of :-

❖ ARMS

❖ HANDS

❖ FINGERS

❖ FINGERNAILS


-ARMS-

• Arms should be inspected for any primary or secondary skin lesion, such as those of lichen planus, erythema multiforme, or vesiculobullous lesions.

The skin may exhibit-

• Bruising

• Loss of pigmentation

• The yellowing of jaundice

• Cyanosis


BRUISING

• Also called as contusion.

• Type of hematoma of tissue in which capillaries are damaged by trauma.


YELLOWING OF JAUNDICE

“Jaundice is defined as yellow discolouration of skin and mucous membranes due to increased Serum Bilirubin.”

• Varies from faint yellow of viral hepatitis to dark olive greenish yellow of obstructive jaundice.

• Normally serum bilirubin is less than 1 mg/deciliter.

• More than 2 mg/deciliter makes its color apparent.



• Best seen on bulbar conjuctiva.

• jaundice can not be seen well in artificial light.

• It must be seen in daylight only.


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6

HOW TO EXAMINE JAUNDICE-


The places where one should look for jaundice are-

Sclera of the eyeball, nail bed, lobule of the ear, tip of nose , under surface of the tongue.

• In rare cases yellowness may be due to :

- carotenaemia.

- tobacco stains on the fingers, face.


CYANOSIS

“bluish discoloration of the skin and mucous membrane due to increased amount of reduced hemoglobin in capillary blood.”

P.J Mehta’s Practical Medicine 17th Edition

TYPES-Central cyanosis

Due to inadequate oxygenation of blood in lungs.

Peripheral cyanosis

Excessive reduction of oxyheamoglobin due to diminished blood flow .


CENTRAL PERIPHERAL

1. mechanism Diminished arterial oxygen saturation

Diminished flow of blood to local part

2. sites Skin and mucous membranes(tongue ,lips)

skin only

3. temp of limbs warm cold

4. clubbing and polycythemia

usually associated Not associated

5. local heat cyanosis remains cyanosis abolished


-HANDS AND FINGERS-

• Overall size of the hands should correspond with the build of the patient.

• Size, length and joints of the finger should be inspected for redness, enlargement, and limitation of functions.


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7

-FINGERNAILS-

• Fingernails can reveal indications of systemic disease.


NAIL-


CLUBBING

“clubbing is bulbous enlargement of soft parts of the terminal, phalanges with both transverse and longitudinal curving of the nails”


CAUSES OF CLUBBING-

➢ PULMONARY CAUSES-

Lung abscess

Tuberculosis with secondary infections

➢ CARDIAC CAUSES-

Infective endocarditis


• The angle of the nail to the skin should not exceed 160DEG. This is called LOVIBOND’S ANGLE .

• And it determines whether a nail is clubbed.


GRADES-

I. Softening of nail bed

II. Obliteration of the nail bed

III. Swelling of the subcutaneous tissue(resulting in parrot beak or drumstick appearance)

IV. Swelling of the fingers in all directions


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8

CLASSIFICATION OF CLUBBING

According to FISHMAN.

❑Normal

❑Mild

❑Moderate

❑severe


SCHARMROTH’S SIGN


IN KOILONYCHIA:

• nails have a spoon shape and are concave.

-seen in Iron deficiency anaemia.

SPECIFIC DISEASES OF NAILS


SPECIFIC DISEASES OF NAILS-ONYCHOMYCOSIS –

Fungal Infection Of Nail

ONYCHOLYSIS-

keratin Deposition Beneath Nail Bed. Occurs In Psoriasis


TERRY’S NAIL:-

• Whitening of the nail bed.

• Manifestation of hypoalbuminaemia.


NAIL BED INFARCTS:-

• May occur in vasculitis especially in systemic lupus erythematosus and in polyarteritis.


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9

BITTEN NAILS:-

• Suggest anxiety neurosis.


-VITAL SIGNS-

• Vital signs incluid –

• Blood pressure

• Pulse rate

• Respiration rate

• Oral temperature


BLOOD PRESSURE

• Normal range-120/80mmHg

Blood pressure recording technique includes-

• placement of cuff

• Support arm at the level of heart

• Palpation of radial artery and placement of stethoscope

• Take two measurements at each visit


CONDITIONS DIGNOSED BY MEASURING BP

• HYPERTENSION-

Systolic Diastolic

Stage 1 140-159 90-99

Stage 2 160-179 100-109

Stage 3 >180 >110

CAUSES OF HIGH BLOOD PRESSURE-

• RENAL DISEASES- Renal vascular diseases


• ENDOCRINE DISEASES -hyperparathyroidism

- Thyrotoxicosis

- Primary hypothyroidism

CAUSES OF HYPOTENSION-

- Severe aortic stenosis

-Arrhythmia


PULSE RATE

• PULSE RATE:Pulse rate can be taken as the dentist palpates the radial artery for the blood pressure reading.

• When taking the pulse, the examiner should use the fingertips rather the thumb.

• The pulse rate is recorded in beats per minute and the normal value is 72.

• Pulse rate- Bradycardia <60bpm

Normal 60-100bpm

Tachycardia >100bpm


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10

• NORMAL PULSE RATES-





AGE 6-12 -75 to 105bpm



RESPIRATORY RATE

• The rate of respiration is the number of inspirations recorded during 1 minute.

• Respiration is usually rhythmic but not always regular.

• The rate should be counted by watching the patient’s chest rise and fall.


• The normal rate for an adult is approximately 14 to 18 per minute.

• The normal respiration has regular rhythm with inspiration longer than expiration.


• Normal breathing in males is-

ABDOMINOTHORACIC

• both the abdomen and thorax are moving during the act of respiration but the abdominal movements are more prominent.

• Normal breathing in females is –

THORACOABDOMINAL

• the thoraic movements are more prominent than abdominal movements.


TEMPERATURE

• Patient oral temperature should be recorded.

• This is accomplished using an oral thermometer.

• Normal oral temp. is 98.6 F +/- 0.5.

• Infection, Inflammation are common cause of elevated temperature.


• A hypermetabolic state such as hyperthyroidism can also elevate the patient’s temp.

• Hypothermia /decrease in temp. can be associated with a hypometabolic state such as myxedema.

• Oral temp.- 98.6F/37.0C

• Axillary- 97.6F/36.3C

• Rectal- 99.6F/37.7C

• Aural- 99.6F/37.7C


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EXAMINATION OF HEAD

It includes-• Face• Hair • Skin• Eye• Ear• Pre and post auricular lymph nodes• Nose • Paranasal sinus• Temporo-mandible joint• Parotid gland


FACE

• Overall facial form should be evaluated for proper positioning of the maxilla and mandible in relation to the rest of the skull.


Facial Form-

i) Mesoproscopic: average or normal face form

ii) Euryproscopic : broad and short

iii) Leptoproscopic: long and narrow

Orthodontics The Art And Science 5th Edition S.I Bhalajhi

• The presence and location of swelling should be noted on the face.

➢ A unilateral swelling –may be cellulitis or salivary gland tumor.

➢ A bilateral swelling-may be significant in disturbances of the temporomandibular joint.


SKIN

• Skin should be examined for color, texture, elasticity and presence or absence of edema.

EVALUATION OF THE TEXTURE OF THE SKIN-

• Texture can be evaluated by light palpation.

EVALUATION OF THE ELASTICITY OF THE SKIN-

• Normally elastic skin goes back into place.

• Poor hydration is common cause of loss of elasticity.


HAIR

• Hair should be evaluated for the pattern of distribution, color, and texture.


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12

EYE

• The eye ball should be evaluate for size and shape.

• If the eye appears to protrude abnormally, the examiner may suspect EXOPHTHALMOS.


• Exophthalmos is present when the horizontal distance between the outer canthus to the most anterior edge of cornea exceeds 16 mm when sited from the lateral aspect.


• When eye ball is pushed forward due to increase in fat or edema, the eye lids are retracted and sclera become visible below the lower edge of iris first followed by the above the upper edge of iris.


EAR

• The ear should be inspected visually for abnormal nodules or distortion.

RUDIMENTARY EAR-


•A rudimentary tag of ear tissue, often containing a core of cartilage, usually located just in front of the ear.

•This minor anomaly is common and harmless.

• Also known as preauricular tag.

http://www.medicinenet.com/script/main/art.asp?articlekey=12759

http://www.medicinenet.com/script/main/art.asp?articlekey=5017

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13

GENERAL, PHYSICAL AND EXTRAORAL EXAMINATION

Dr Hina Tyagi

PG 1st Year

QUESTIONS

Q: Emaciation of the face?

• The face gradually becomes very much thin with somewhat vacant appearance.

• The eye sockets become so much sunken than eyes appear bulged.

• Very dry scalp along with severe degree of loss of hair.

• Excessive drying and coating of tongue and bad breath.

POSTURE

SCOLIOSIS

LORDOSIS

KYPHOSIS


TETROLOGY OF FALLOT

>4 components of tetrology of fallot-

1.Ventricular Septal Defect

2.Pulmonary Stenosis

3.Right Ventricular Hypertrophy

4.Overriding of Aorta

Davidson’s principle and practice of medicine

TYPES OF HAIR IN SOME DISEASE

Changes in hair that occurs in some of the disease are-

1.FALLING OF HAIR- In Typhoid

2.PATCHY HAIR LOSS-Alopecia


LOSS OF OUTER THIRD OF THE

EYEBROWS- MyxodemaABSENCE OF FACIAL HAIR-

Hypopituitarism


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14

• EXCESSIVE HAIR GROWTH IN WOMEN-

• Cushing’s syndrome.


• In previous part general appraisal of the patient and examination of the head has been covered.

• In examination of the head facial form, skin, hair, eyes and ear has been covered.

CONTENTS

>EXAMINATION OF HEAD

1.Temporomandibular joint

2.Nose and paranasal sinus

>EXAMINATION OF NECK

1.Lymph nodes

2.Salivary glands

3.Thyroid gland

4.Trachea

5.Carotid artery

>NEUROLOGICAL EXAMINATIONOral Diagnosis,oral Medicine,and Treatment Planning 2nd Edition Bricker,langlaise,miller

EXAMINATION OF THE HEAD

TEMPOROMANDIBULAR JOINT

Gray’s Anatomy For Students

• The two temporomandibular joints allow opening and closing of the ‘mouth’, ‘chewing’ or ‘side-to-side’ movements of the lower jaw.

• Each joint is synovial in type and is formed between the head of the mandible and articular tubercle of the temporal bone.

• Both joint should be palpated at the same time.

• Examiner can be positioned either in front of or behind the patient.


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15

PALPATION OF TEMPOROMANDIBULARJOINT

• If any deformity is their then clicking, or grating sound present.

• Abnormal sound indicate any dysfunction or internal derangement of the joint.

• There are 2 types of joint sounds-

Clicks - single explosive noise

Crepitus - continuous 'grating' noise


• Clicking and crepitus can be better appreciated by auscultation with stethoscope.

CLICKING-

• Indicated displaced articular cartilage of TMJ.

• More common in females.

• Clicking can be heard when patient open the mouth every time.


• Locking of the jaw occur suddenly when patient open the mouth during yawning and fails to close the mouth.

• Condylar movement can be palpated through the anterior wall of the external auditory meatus.


NOSE AND PARANASAL SINUS

NOSE-

• The nose is shaped by the cartilage within the tissue and can be easily fractured.

• Fractures may lead to deviations that may cause mouth breathing and associated abnormalities.


• Nose is made up of the :

- Bridge

- Tip

- Alae

- Base

- Septum and

- External nares which are separated by the clumella


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16

PARANASAL SINUSES

There are four Paranasal air sinuses-

• The Ethmoidal cells

• The Sphenoidal

• Maxillary sinus

• Frontal sinuses.

Frontal and Maxillary sinuses are major sinuses and most commonly examined.

Gray’s Anatomy For Students

FRONTAL SINUS

• It lies in midline above the eyes.

• Can be palpated and percussed with the fingers which may produce –

-Pain, discomfort, if sinuses are inflamed.


PALPATION OF FRONTAL SINUS MAXILLARY SINUS

The maxillary sinuses, one on each side, are the largest of the paranasalsinuses.

• Each is pyramidal in shape


PALPATON OF MAXILLARY SINUS

EXAMINATION OF NECK

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17

Examination of neck

• Visual inspection of neck is used to note -

-Abnormal swellings

-Skin changes

-Dysfunction of muscles

-Distention of blood vessels


Structures in the neck to be evaluated are :

-THE MUSCLES

-SUBMANDIBULAR AND SUBLINGUAL SALIVARY GLANDS

-LYMPH NODES

-THYROID GLAND

-TRACHEA

-CAROTID ARTERY.


• The two major triangles of the neck are:

- ANTERIOR TRIANGLE

- POSTERIOR TRIANGLE

• Which are separated by the sternocleidomastoid muscle.


Anterior triangle is divided into:

• SUBMANDIBULAR TRIANGLE

• CAROTID TRIANGLE

• SUBMENTAL TRIANGLE

• MUSCULAR TRIANGLE


• Posterior triangle is divided into-

• OCCIPITAL TRIANGLE

• SUBCLAVIAN TRIANGLES

• Separated by the Omohyoid muscle.


MUSCLES OF NECK

Sternomastoid and trapezius muscle are commonly examined muscles in neck.

STERNOMASTOID MUSCLE-

Origin– sternum and clavicle

Insertion-mastoid process.

• Can be identified by having the patient rotate his unsupported head.


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18

TRAPEZIUS MUSCLE-

Origin-Occipital bone

Insertion -posterior border of the clavicle and scapula.


CLINICAL IMPLICATION

• Tenderness in either of these muscles or their attachments to bone can indicate a state of tension & may be a clue to the presence of myofascial pain dysfunction syndrome.

• Tenderness along the Sternomastoid muscle may be from the muscle itself or from lymph nodes that are pressing against it.


LYMPH NODES

• Groups of lymph nodes-1) Preauricular 2) Postauricular 3) Submandibular 4) Submental 5) Anterior cervical6) Posterior cervical7) Suboccipital8) supraclavicular


Examination of Lymph Node-• Inspection :

-Most of the superficial lymph node are visible when enlarged.

-Site of lymphadenopathy gives the clue to its cause.


• Palpation:

-Raised temperature and tenderness is noted.

-Surface is smooth normally but matted in Tuberculosis and irregular in malignancy and inflammation.

-consistency of the nodes is noted.

normally – firm

Hodgkin's disease-rubbery

malignancy- hard


• Mobility of the nodes is noted.

Normally-mobile & free from skin.

Malignancy-fixed & non mobile.

P.J Mehta’s Practical Medicine 17th EditionP.J Mehta’s Practical Medicine 17th Edition

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19

PALPATION OF PREAURICULAR AND POSTAURICULAR LYMPH NODE


PALPATION OF SUBMANDIBULAR


PALPATION OF SUBMENTAL


PALPATION OF CERVICAL LYMPH NODES

ANTERIOR CERVICAL POSTERIOR CERVICAL


PALPATION OF SUBOCCIPITAL PALPATION OF SUPRACLAVICULAR


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20

LEVELS OF LYMPH NODES Level I:

SUBMENTAL AND SUBMANDIBULAR NODES

– LEVEL IA: Submental - found between the anterior belly of the digastric muscles.

– LEVEL IB: Submandibular triangle - found around submandibular glands in submandibular space.

"An Imaging-based Classification For The Cervical Nodes Designed As An AdjunctTo Recent Clinically Based Nodal Classifications.”

Level II: UPPER JUGULAR NODES -Between posterior belly of digastric muscles superiorly and hyoid bone inferiorlyLEVEL IIA: Anterior, medial, lateral or posterior to internal juglar

vein, or if posterior, must not have an intervening fat plane.LEVEL IIB: Posterior to internal jugular vein with fat plane between

nodes and internal jugular vein

LEVEL III: MIDDLE JUGULAR NODES -between the hyoid bone and cricoid cartilage

LEVEL IV: LOWER JUGULAR NODES -between the cricoid cartilage and the clavicle

• LEVEL V: POSTERIOR CERVICAL• posterior to the sternocleidomastoid muscle

– Level VA: lymph nodes from skull base to bottom of cricoidcartilage

– Level VB: lymph nodes between cricoid and clavicle

• LEVEL VI: VISCERAL SPACE LYMPH NODES –midline group of cervical nodes from hyoid bone to sternal manubrium.

• LEVEL VII: SUPERIOR MEDIASTINAL NODES -between carotid arteries from top of manubrium superiorly to innominate vein inferiorly.

LYMPHADENOPATHY

LYMPHADENOPATHY DRAINING AREAS

1. Anterior cervical lymphadenopathy Anterior 1/3 of scalp, facialstructures, thyroid gland

2. Posterior cervical lymphadenopathy

Posterior2/3 of scalp and thyroid gland

3. Preauricular lymphadenopathy Local scalp lesion, external auditory meatus, forehead.

4. Submental and submandibular lymphadenopathy

Tongue, floor of mouth and pharynx


HODGKIN’S DISEASE

• Causes cervical lymphadenopathy.

• Patient may have history of night sweating.

• Early diagnosis is critical because disease responds well to early therapy.

• Lymph nodes are non tender, nonsuppurative, discrete.


VIRCHOW’S NODE

• Lymphadenopathy of the left supraclavicular fossa due to metastasis from stomach carcinoma.

• Patient with recent history of weight loss and abdominal complaints.


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21

SALIVARY GLAND

The major salivary glands are:

• The parotid

• Submandibular

• Sublingual glands

F. Christopher Holsinger and Dana T. Bui

PAROTID GLAND

• The paired parotid glands are the largest of the major salivary glands and weigh,on average,15–30gm.

• Located in the preauricular region and along the posterior surface of the mandible.

• Parotid gland is divided by the facial nerve into a superficial lobe and a deep lobe.


STENSEN’S DUCT

• The parotid duct,also known as Stensen’s duct, secretes a serous saliva into the vestibule of the oral cavity.

• It enters the oral cavity opposite the second upper molar tooth .


SUBMANDIBULAR GLAND

• The submandibular gland is the second largest major salivary gland and weighs 7–16g.

WHARTON’S DUCT-

The main excretory duct.

F Christopher Holsinger and Dana T. Bui

EXAMINATION

• The superficial location of the salivary glands allows thorough inspection and palpation for a complete physical examination.

• During the initial extraoral inspection, the patient Should stand 3 to 4 feet away and directly facing in front of the examiner.


• Enlargement of major or minor salivary glands, most commonly the parotid or submandibular, may occur on one or both sides.

• Parotitis typically presents as preauricular swelling.


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22

• Submandibular swelling presents just medial and inferior to the angle of the mandible.

• In addition to signs of possible asymmetry, discoloration, or pulsation, intraoral inspection includes assessment of the duct orifices and possible obstructions .


• The openings of Stensen’s and Wharton’s ducts can be inspected intraorally opposite the second upper molar and at the roof of the tongue, respectively .

• Drying off the mucosa around the ducts with cotton and then pressing on the corresponding glands will allow the examiner to assess the flow or lack of flow of saliva .


• Bimanual palpation (extraoral with one hand, intraoral with the other) must be performed to examine the parotid and submandibular glands .


THYROID GLAND

• Thyroid gland is located in the midline of the neck.


INSPECTION

• Normally thyroid gland is not obvious on inspection.

• It can be seen only when the thyroid gland is swollen.

• for easier inspection one can follow Pizzilo’s method.

• Thyroid swelling moves upward on deglutition.


PALPATION

• Thyroid gland should always be palpated with the patient’s neck slightly flexed.

• Gland can be palpated from behind and from front.

• Palpation of lobe is best carried out by Lahey’smethod.


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23

• During palpation following points should be noted.

1. Whether the whole thyroid gland is enlarged

2. Mobility

3. Pressure effect


TRACHEA

• The trachea is examined above the suprasternalnotch to a certain ascertain whether any lateral displacement caused by thyroid enlargement or a tumor.


Carotid artery

• Carotid artery can be palpated in the carotid triangle.

• Only one side at a time should be palpated.

PALPATION-Fingers of the right hand

should be placed in the left carotid triangle and with gentle pressure.


• The force of the pulse should be noted.

• Forceful pulsations may indicate hypertension or Thyrotoxicosis.

• An expansile pulse may be due to an aneurysm.


NEUROLOGIC EXAMINATION

• Confused speech, lack of orientation in time and space, and inability to follow simple directions are clues to an altered mental status.

• Alteration in gait, posture,and balance may be induced by neurologic changes.

• Tremors either suggest a neurologic disorder or may occur in association with psychology disorders.


EVALUATION OF THE CRANIAL NERVES

I. Olfactory

II. Optic

III. Oculomotor

IV. Trochlear

V. Trigeminal

VI. Abducens

VII. Facial

VIII.Acoustic

IX. Glossopharyngeal

X. Vagus

XI. Accessory

XII. Hypoglossal


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I-OLFACTORY

Smell: Test ability of each nostril to distinguish familiar smells as peppermint, eugenol, coffee.

II-OPTIC

• With changes of the optic tract patient may complain of blurred vision or loss of vision.


• III ,IV & VI CRANIAL NERVES

• These nerves supply muscles of the eye and responsible for eye movement.

• Oculomotor allows a person to look up and down and returns the eyes medially.

• Trochlear turns the eye downward and inward.

• Abducens also turns the eye laterally.


V TRIGEMINAL NERVE

• It has both sensory and motor functions.

• 3 divisions of the trigeminal nerve-

1.Opthalmic division

2.Maxillary division

3.Mandibular division


DIVISION SUPPLY 1.Opthalmic Conjunctivae, cornea, iris, lacrimal

glands, eyelids.

2.Maxillary Maxillary teeth, mucous membrane of the nose, hard and soft palates, tonsillar area, pharynx.

3.Mandibular Mandibular teeth, gingiva, mucous membranes of tongue.


VII FACIAL NERVE

• Facial nerve lesions cause droop and weakness.

• When the nerve is diseased, the muscles on the affected side do not contract.

• When the right and left facial nerves are both normal, lips part symmetrically, both eyes close equally, and the entire forehead wrinkles.


• When abnormalities are present, patient may have one of the smiling, eye closing, forehead wrinkling.

• Taste can be tested (though rarely done) with salt/sweet solutions.

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VIII ACOUSTIC

• Hearing: Ask to repeat a number whispered in an ear while you block the other.

• Perform Weber's and Rinne's tests.

• Impaired function history reveals tinnitus, vertigo, and dizziness.


IX & X (GLOSSOPHARYNGEAL AND VAGUS)

• Gag reflex: Touch the back of the palate with a spatula to elicit a reflex contraction.

• X lesions also cause the palate to be pulled to the normal side on saying “aah-aah”.


XI-ACCESSORY NERVE

• Motor function to the trapezius as Shrug shoulders against resistance.

• To Sternocleidomastoid as turn head to the left/right against resistance.


XII-HYPOGLOSSAL

• If the nerve is not functioning properly, the tongue will deviate toward the nonfunctioning side when it is protruded from the mouth.


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INTRAORAL EXAMINATION, DIAGNOSIS & TREATMENT

PLAN

Dr. Amrita Aggarwal


MGDC&H, Jaipur

INTRAORAL EXAMINATION INCLUDES EVALUATION OF:

Soft tissue examination

1.Lips.

2.buccal mucosa.

3.mucobuccal fold.

4.Soft palate.

5.Uvula

6.Oropharynx

7.tongue.

8.Floor of mouth

9.Muscles of mastication

Oral diagnosis ,medicine, treatment planning, steven l bricker- 2nd edition

10.Periodontium

11.Hard palate.

12.Teeth


Hard tissue examination

Soft tissue examination

LIPS AND LABIAL MUCOSA

• The muscular control of the lips canbe evaluated during conversation.

• At rest lips normally touch, if theyare apart it may indicate mouthbreathing ,tongue thrusting , ornasal obstruction.

Oral medicine,oral diagnosis and treatment planning, S.L bricker 2nd edition

• The vermilion border should be evaluated for colour,texture, and fissuring.

• Visual inspection may reveal unilateral or bilateralswelling of lip.


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• Function of the mucous glands may be assessed by everting thelip, drying it and watching for beads of saliva to accumulate.

• By using bidigital palpation the lips can be examined forsubmucosal nodules, mass,and other abnormalities

Oral medicine,oral diagnosis and treatment planning, S.L Bricker 2nd edition

- Move the tissues from side to side and visualize the frena. Normal lip tissues are a homogenous deep pink color which changes gradually to a deep red color with more prominent vascularity near the mucolabial vestibule.

- The tissues should be moist and have uniform consistency and thickness when palpated

Crest® Oral-B at dentalcare.com Continuing Education Course, February 19, 2009

The commissures should be clear of

lesions and should not show signs ofcracking or dryness .

Common pathological conditionswhich affect the commissures includeangular cheilitis, Candida Albicans,nutritional deficiencies.


Sclerotic minor salivary glands are common atypical findings as are Fordyce’s granules.

Pathologic findings include the following:

• Traumatic injuries – abrasions, lacerations

• Dry, cracked lips

• Angular cheilitis

• Aphthous ulcers


BUCCAL MUCOSA

Topographic anatomy:

• The buccal mucosa proper is the lining of the cheek.

• The actual surface of the cheek is covered by squamousmucous membrane of varying thickness.


• On the buccal mucosa near to the second molar tooth is the parotid papilla which is an elevation containing the opening of the stensen’s duct from parotid gland.


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• A white line is seen coressponding to the line of occlusion ,this line is caused by the buccinator muscle pressing the mucosa over the cusps of the teeth .

• It is a hyperkeratotic and called as linea alba.


• At the posterior boundary of the buccal mucosa is a fold of tissue called pterygomandibular raphe.

• Both buccinator and superior constrictor pharyngeusmuscle originate at this site.


• Fordyces granules andleukoedema are conditionsconsidered to be variation inthe normal topographicanatomy.

• Fordyces granules are theectopic sebaceous glandsmost frequently found on thelips and buccal mucosa ,theyappear as small,yellow,nodulesfound in cluster .


TECHNIQUE

The buccal mucosa is examined usingdirect and indirect vision followed bybi-digital palpation of the entire area.Be sure to pull the tissues away fromthe retromolar area and stretch themucosa away from the mucogingivaljunction.

The buccal mucosa should bebidigitally palpated pressing the tissuebetween the index finger and thumbof one hand .

.Crest® Oral-B at dentalcare.com Continuing Education Course, February 19, 2009

Normal tissues of the buccal mucosaappear moist and red. They are soft andpliable on palpation with no discernibleindurations


You may also feel small papules within the tissues usually indicative of sclerotic or fibrotic minor salivary glands.

Varicosities may often present on the buccal mucosa of older patients.

The buccal mucosa is also a prime area for stress related habits such as cheek chewing (morsicatio buccarum).


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Pathologic findings associated with thebuccal mucosa include:

• Traumatic injuries – thermal burns,cheek bites, ulcers, traumatic fibroma.

• Leukoplakia associated with spittobacco.


• Neoplastic changes – erythroplakia, speckledleukoplakia and pigmented lesions

• Systemic disease states-oral lichen planus, lipomas,aphthous ulcers, erythema multiforme.


MUCOBUCCAL FOLD


• The major structures of the mucobuccal folds are the labialfrena .

• Improper attachment of the labial frena can contribute tothe mucogingival problems .

• High insertion of the frena may disturb prostheses bydislodging denture bases.


Technique :

• The mucobuccal fold shouldbe inspected visually and bypalpation .

• By running the finger over thebone at the fold , nodules orpainful areas can bediscovered .


SOFT PALATE AND UVULA


o Soft palate is a thin muscularcurtain that separates the mouthfrom the nose.

o On its posterior border in themidline is the uvula.


o The mucosa of soft palate is thin but overlies thickvascular connective tissue and muscle, therefore it

has a redder appearance.

o Sometimes it has yellowish appearance because ofthe presence of underlying adipose tissue.

o Its forms the covering over the superior constrictor musclesof the pharynx and continues anteriorly in the nose, first astransitional epithelium , then as nasal epithelium.


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Technique :

✓ The soft palate can be seen by useof the mouth mirror and reflectedlight as well as by depressing thetongue .

✓ Soft palate can be palpated by using the index finger and pressing upward.


The tissue should appear loose, mobile and symmetricalduring function. The tissue will have a homogenous, spongyconsistency on palpation.

Atypical observations include yellowish coloring due toincreased adipose tissue (especially in older patients),excessively long or short uvulas and uvulas that appear slightlyasymmetrical at rest. Occasionally one will discover a bifid(cleft) uvula.


OROPHARYNX AND NASOPHARYNX

Topographic anatomy :

The most anterior part of thelateral wall of the oropharynx arecalled the tonsillar fossae.

The tonsillar fossae is boundedanteriorly by the anterior

pillar,which is formed by thepalatoglossus muscle. Theposterior pillar is formed by the

palatopharyngeal muscle.


The space between the two pillarscontains the palatine tonsil.

Posteriorly the oropharynx is boundedby the posterior pharyngeal wall,superiorly by posterior border of thesoft palate, and inferiorly by the hyoidbone.

The nasopharynx border are the choanae anteriorly, the pharyngeal wall posteriorly, the first two cervical vertebrae superiorly, the soft palate inferiorly


When the nasopharynx is viewed,the vomer bone is seen in themidline with the choanae on eitherside of it but not attached to it.

The pharyngeal tonsils of thenasopharynx,the palatine tonsil ofthe oropharynx and the lingualtonsil of the tongue makes up a circleof lymphoid tissue called waldeyer’sring.


Technique :

The entire length of the anteriortonsillar pillar should be palpatedfor the presence of submucosalmasses

The oropharynx may be examined by placing the mirror on the dorsum of the patient ‘s tongue and depressing the tongue downward and forward


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The nasopharynx is more difficult to view the tongue is depressed by the tongue blade and the mirror placed in the back of the oropharynx almost to the posterior pharyngeal wall, the mirror is than rotated to see the nasopharynx.


Pathologic findings include:

• Homogenous and non-tender erythema associated with postnasal drip and/or smoking

• Erythema and purulent exudate associated with pharyngitismaycover portions of the pharyngeal wall

• Ulcers, erosions or noticeable enlargements or growths


TONGUE


Tongue is a muscular organ

Dorsum of tongue is covered by 4 types of papilla

1.Filliform2.Fungiform3.Cicumvallate4.foliate

Filliform papillae are the most numerous one and cover mostof the dorsum of the tongue, they appear as small ,whitishhair like projections.

The whitish color is due to the amount of keratin and issusceptible to discoloration by extrinsic stain. They maybecome elongated or shotened. they do not contain tastebuds.

The second most numerous group of papillae are the smallmushroom shaped elevations scaterred among the filliformpapillae, called fungiform prominent


They do not have keratin,they are redder and may be pigmented,these papilla contain taste buds.


Posteriorly on the tongue are 8 to 12 large cicumvallate papillae,they are round and have a groove around them and alsocontain taste buds.

Finally the foliate papillae, located on the lateral borders of thetongue, they are not as easily identified, foliate means leaf like,they contain taste buds.

The midline of the tongue has a depression called mediansulcus

The median sulcus followedposteriorly to end in a V or a Y shapecalled terminal sulcus.,this sucusseparates the dorsum of the tonguefrom the root.

At apex of the terminal sulcus lies asmall depression sulcus called theforamen cecum, which is the oralremnant of the thyroglossal duct.

The lingual tonsils are on the root ofthe tongue,posterior to the terminalsulcus.


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The lingual frenum is located on theventral surface of the tongue and attachesto the genial tubercles of the mandible.

On either side of frenum is a small line oftissue projections ,the plica fimbriata.Deep seated areas of bluish discolorationon the ventral surface of the tongue arethe lingual veins.

With age these veins may form numerouspurple varicosities.


Atypical findings on the dorsal surface of the tongue are common.They include: fissuring scalloping benign migratory glossitis andenlarged papillae.

Technique :

The tongue is best seen with the patient’s mouth wideopen.

Tongue should be examined for:

Size, Shape, fissural pattern, length of the papillae,change in keratin retention, change in colour, elevation,depressions, shape of the borders.


To see all surfaces of the tongue ,agauze is used to retract the tongueforward, to the left, to the right, andupward.

The entire body of the tongue shouldbe examined bidigitally ,avoidingdorsum of the tongue near the rootwhere the gag reflex may bestimulated.


Pathological findings that are found on the tongue include:

• Hairy tongue – filiform papilla become elongated due to a variety of reasons from overuse of mouth rinses to not cleaning the tongue adequately.

• Candidiasis – fungal infection of the tongue often associated with deeply fissured tongues.

• Glossitis – inflammation of the tongue due to anemia, nutritional deficiencies and others

FLOOR OF THE MOUTH


Lingual frenum divides the floor ofthe mouth into two halves.

The sublingual caruncles are seen astwo small projection on either sideof the frenum and are oftenattached to the frenum.


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They are site of opening ofwharton’s ducts from the left andright submandibular gland.

From caruncles the sublingualfolds seen as elevation runningposteriorly , contains wharton’sduct and part of the sublingualsalivary gland and their ducts.


The area between the mucous membrane of the floor ofthe mouth and the skin of the sub mandibular region ofthe neck, contains the sublingual gland, submandibulargland, mylohyoid muscle, numerous lymph nodes.


Technique :

The floor of the mouth is examined usingdirect and indirect vision followed bybimanual palpation of the entire area.The patient should be asked to raise thetongue making direct visual examinationof the tissues toward the midline of thefloor of the mouth possible .

The mirror should be used to examinethe areas near the inferior border of themandible.

The caruncles can be blotted dry and the function of the submandibular gland evaluated by pressing the gland, thereby expressing saliva from the duct opening.

The posterior floor and the lingual border of the alveolar ridges can be viewed by retracting the tongue with a mirror.

Bimanual palpation is done byplacing index finger of one handon the area to be palpated andthe fingertips of the opposinghand in the submandibular area.

Entire floor of the mouth shouldbe palpated starting from theposterior proceeding anteriorly tothe opposite side


Varicosities are the most commonatypical observation in this area.Other atypical findings areenlarged lingual folds and caruncleand a short lingual frenum(ankyloglossia).

Ankyloglossia is only considered aproblem if it begins to affect thespeech development of theindividual.

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• Traumatic injuries –ulcer,mucoceles.

•Salivary gland pathology – ranula,sialoliths,enlargement

• Neoplastic changes

• Ankyloglossia – this is consideredpathologic only if it interferes withthe normal development of properspeech

Other pathological findings include:MUSCLES OF MASTICATION

These muscles are

temporalis,

masseter

lateral pterygoid

medial pterygoid

The objective of this examination is to identify any areasof pain or presence of any abnormalities.


1.Temporalis muscle

This muscle originates in the

temporal fossa of the temporalbone and insert on thecoronoid process and anteriorborder of the ramus of themandible


Temporalis muscle can be palpated throughout itslength and breadth when the patients teeth are firmlyclenched.

2.Masseter muscle

This muscle originates from the lower portion of thezygomatic arch and inserts on the lateral surface of theangle and coronoid process of mandible

It has a superficial portion and a deep portion.


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It can be located when the jaw of patientare forcibly closed.

The body of masseter muscle can bepalpated with the thumb and index finger.

Index finger can palpate the entire bodyof the muscle

The deeper portion is palpated throughthe sigmoid notch.


3.Medial pterygoid

This muscle originates fromthe medial side of the lateralpterygoid plate and thetuberosity of maxilla.

The muscle inserts on thelower medial surface of theramus of mandible


The anterior part of the insertion canbe palpated by placing the indexfinger at 45 degree angle in the floorof the mouth near the base of therelaxed tongue

The body of the muscle is palpatedby rotating the finger against themuscle towards the tuberosity Theopposite hand can be usedextraorally to palpate the posteriorand inferior portion of the insertion.


4.Lateral pterygoid

This muscle originates in twoparts :

One begin on the greater wing ofthe sphenoid bone and theother from the lateral surface ofthe pterygoid plates.

These parts inserts on the neckof the condyle and articular discof the Temporomandibular joint .


Two portions or bellies:

Inferior head

Superior head

Inferior head is about three times larger than the superior head

Superior head

Inferior head

This muscle can be palpated using index finger , placing itlateral to the maxillary tuberosity and medial to thecoronoid process . the finger presses upward and inward anda painful response can be determined because thisprocedure is uncomfortable for the patient. the response ofboth sides weighed for determination of abnormal function.


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QUESTIONS

1. Why physiologic pigmentation occur ?

Physiologic pigmentation is common in African, Asian, andMediterranean populations,it is due to greater melanocyte activityrather than a greater number of melanocytes. Physiologicpigmentation develops during the first decades of life but may notcome to the patient's attention until later. The color ranges fromlight to dark brown. The attached gingiva is the most commonintraoral site of such pigmentation, where it appears as a bilateral,well-demarcated, ribbon-like, dark brown band that usually sparesthe marginal gingiva. Pigmentation of the buccal mucosa, hardpalate, lips, and tongue may also be seen as brown patches withless well-defined borders. The physiologic pigmentation isasymptomatic, and no treatment is required.

Contemp Clin Dent. 2010 Jul-Sep

2.Nerve supply of uvula?

4.Uvula deviates to one side in which disease?

3. Accessory muscles helping in mastication?

They are infra hyoid muscle and are as follows

Digastric muscles

Mylohyoid muscle

Geniohyiod muscle

buccinator

CONTENT1. Intraoral examination.

-soft tissue examination.

-hard tissue examination.

2.Diagnosis

-Provisional diagnosis

- differential diagnosis

-aids to diagnosis

-final diagnosis

3.Treatment plan

Hard tissue examination

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HARD PALATE


✓ The incisive papilla is located in the midline just posterior to themaxillary central incisor teeth, this elevation is the anteriortermination of the palatine raphe.

✓ Just behind incisive papilla and running transversely on either sideof the midline are the palatine rugae.


✓ Junction of the hard and soft palate iscalled the vibrating line.

✓ Just anterior to the vibrating lines oneither side of the palatine raphe are twosmall depressions called the foveapalatinae.

✓ The posterior portion of hard palateextends laterally to the last maxillarymolar teeth and the rounded maxillarytuberosities .


Technique:

• The hard palate can be inspected visually both directly andindirectly through the use of mouth mirror.

• It appears pale pink because it is covered with keratinizedepithelium with a shallow layer of dense connective tissuebeneath.


• The rugae should feel dense and firmlyattached near the midline and becomemore resilient as they run laterally.

• The contour of the vault should be noted.

• Using finger ,entire area can be palpated .

• Palate should be checked for ulcer ,erythematous areas, swelling andpigmentations.


Diseases of hard palate

Torus palatinus melanosis

PERIODONTIUM


The attached gingiva is firmly bound to bone and is coralpink because of the amount of keratinization,it is clearlydemarcated from the marginal gingiva which is nonkeratinized and movable

The interdental papillae fills the embrasure areasbetween the teeth


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The retromolar papilla and retromolar pad is founddistal to the last molar tooth, the retromolar papillaimmediately distal to the last molar forms a slightelevation that can cause a pseudopocket


Technique :

The periodontium is examined by direct orindirect vision, palpation and probing.

First step is to view the gingiva from bothlabial and lingual aspect.

The change in the colors,shape,surfacetexture

Palpation reveals density,may elicit painmay express pus and may cause bleeding indiseased gingiva


The probe is used to determinethe level of attachment and thedepth of the gingival sulcus.

In addition teeth with bi andtrifurcated roots should beevaluated for loss of bone andfurcation involvement.

All teeth should be evaluatedfor mobility.


TEETH

VISUAL INSPECTION :

Caries pattern:

Caries usually occur in pits and fissures, when home careis extremely poor.

If caries involves multiple cervical surfaces and perhapseven incisive surfaces ,an unidentified cause ofxerostomia must be investigated


If caries are present in the absence of local factors, thepractitioner cannot overlook the possibility that a highsucrose diet has been recently introduced.

Detection of caries:

Probing :- caries in the pits and fissures of teeth may bedetected with a sharp explorer that is pressed into thepit perpendicular to the occlusal plane


Signs of decay as specified by united states public health service are as follows:

1.Softening of the base of pit or fissure.

2.Opacity surrounding the pit or fissure indicating demineralization of the enamel.

3.Softened enamel that may be flaked away by the explorer.


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Smooth surface caries usually begin with a whitedecalcification in the enamel And may not be evident unlessthe teeth is dried. If caries exists the explorer will stick in thelesion.

Root surface caries found below the cementoenamel junction,root caries is often discolored but discoloration alone does notindicate existing caries.,marginal gingivitis isolated to one partof the tooth may be a clue that a carious lesion exist below thearea of inflammation.


Missing teeth:

Clinically missing teeth require investigation throughquestioning the patient regarding the history of removalthrough radiograph to look for unerupted or impacted teeth.


Size, color , structural changes:

Changes from the normal appearance of teeth are basedon the size color, shape or structural defects.

These defects should be checked located visually and ifany deformity is present it should be noted.


Identifying a cracked teeth:

Identifying an individual tooth with a crack require selective pressure on individual cusps.

Biting pressure reproduces pain

Light reflected from various direction may be used to help see the fracture.


Percussion:

A tooth with a large carious lesion should be checked for percussion sensitivity by tapping the tooth lightly with the mirror handle.

Patients response to this tapping is more easily evaluated .

inflammation in the periodontal ligament or in the pulp can cause pain on percussion


Mobility Testing

Mobility can be checked with two rigid instruments such as mirror handles .

Possible causes of mobility include recent removal of orthodontic treatment, loss of periodontal support, trauma from malocclusion, periapical diseases.


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Miller classification for mobility

Class I Tooth can be moved less than 1mm in the buccolingual or

mesiodistal direction

Class II Tooth can be moved 1mm or more in the buccolingual or

mesiodistal direction No mobility in the occlusoapical direction (vertical mobility)

Class III Tooth can be moved 1mm or more in the

buccolingual or mesiodistal direction Mobility in the occlusoapical direction is also present

Evaluation of the malocclusion:

Oral diagnosis ,medicine, treatment planning, Sl Bricker- 2nd edition

TO BE CONTINUED….

diagnosis

PROVISIONAL DIAGNOSIS

Also called as tentative diagnosis, operational diagnosis,working diagnosis, clinical impression.

provisional diagnosis is made based on the positivefindings recorded in the clinical examination.

Based on the provisional diagnosis some investigationsare advised that aids to final diagnosis

Fundamentals of oral medicine & radiology. D.N bailoor,KS nagesh 1st edition

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DIFFERENTIAL DIAGNOSIS

Differential diagnosis may be defined briefly as the rearranging of the list of possible diagnoses, with the most probable one at the top and the least likely one at the bottom.

the actual process of ranking the lesion may become complicated as the clinician attempts to match the features of the lesion being examined with the usual features of the specific lesion in his list.

Differential diagnosis oral & maxillofacial lesions-5th edition N.K Wood , P.W Goaz

To become competent in the art of differential diagnosis, theclinician should be familiar with the sign and symptom of manydiseases

He should also be aware of the relative incidence of thespecific lesion because the in the completed differentialdiagnosis the most commonly occuring lesions are rankedabove.


This order by frequency will then be modified by consideration of

➢ Age

➢ Gender

➢ Race

➢ Anatomic location


CLINICAL AND LABORATORY AIDS TO DIAGNOSIS

Aids used are

✓ Radiograph

✓ Biopsies

✓ Haematology screening

✓ Urinalysis

✓ Bacterial culture


RADIOGRAPHY

Intraoral and extraoral radiographs are used as an aidto diagnosis.

❖ Intraoral radiographs includes:

- periapical

- bitewing

- occlusal


❖ Extraoral radiograph

- Panoramic projection

- Lateral oblique projection

- Skull projection.

- Facial projections

- Temporomandibular joint projection.

- conventional tomography.

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They provide information about the hard and soft tissuethat are hidden from the eye.

They are particularly helpful in studying the bonystructures of the face, jaws, and dental alveoli as well asexamining the teeth.

They can be used effectively to monitor the progress ofthe disease and evaluate prior therapy.


TISSUE BIOPSY

Biopsy is removal of tissue from the living organism for the purpose of microscopic examination and diagnosis.

Types

-incisional

-excisional

-punch

-fine needle aspiration cytology


ORAL EXFOLIATIVE CYTOLOGY

Refers to microscopic examination of exfoliated cells that has been removed from the oral mucosa by scraping.

The lesion is scraped with a moistened tongue blade or a cement spatula.


Cell collected are smeared on a glass slide and fixed, stained and examined under the microscope.

A definitive diagnosis cannot be made through cytology examination.


HEMATOLOGY SCREENING

Red blood cells ,granular leukocytes,monocytes andplatelets are formed in the red bone marrow, andlymphocytes are formed in the lymphoid tissue and thethymus.

Red blood cells supply oxygen to the tissue,the white bloodcells provide protection against extrinsic invaders and soplays an important role in immunologic defense.

Thrombocytes and platelets helps to provide hemostasis.


Any change in the number or quality of these cells can be significant.

A complete blood count (CBC)usually includes:

-Red blood cell count (RBC)

-Hemoglobin determination (Hgb)

-Hematocrit (Hct)

-White blood cell count (WBC)

-Differential white blood cell count (DLC)


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BACTERIAL CULTURE

Culture is done to isolate and identify the causative microorganism of an infection.

After isolation the microorganism is exposed to certain antibiotic agents to determine which affects growth.

FINAL DIAGNOSIS

A final diagnosis is made after careful review ofhistory ,clinical findings and interpretation of the resultsfrom the tests.

Further the treatment plan is based on the finaldiagnosis


Treatment plan

Treatment plan is made based on the final diagnosis

Treatment plan help us in prioritizing the treatment keeping in mind the chief complaint in mind.

TREATMENT PLAN

Fundamentals of oral medicine & radiology. D.N bailoor, KS nagesh 1st edition

Phases of treatment plan:

PRELIMINARY PHASETreatment of emergencies ❖dental or periapical❖periodontal❖others

Carranza’s clinical periodontology -11th edition

NON-SURGICAL PHASE

plaque control and patient education

✓ diet control✓Removal of calculus and root planing✓Correction of prosthetic and restorative irritationalfactors.✓Excavation of caries and restoration.✓minor orthodontic movement.✓Provisional splinting and prosthesis.


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SURGICAL PHASE

✓ Periodontal therapy, including implant placement.✓ Endodontic therapy.

RESTORATIVE PHASE

•Final restorations•Fixed and removable prosthodontic appliance•Evaluation of respone to restorative procedures.•Periodontal examination


MAINTENANCE PHASE

Periodic rechecking✓ Plaque and calculus.✓ gingival condition.✓ occlusion tooth mobility.✓ other pathologic changes


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COMPUTED TOMOGRAPHY

CONTENTS

Introduction

History

Imaging system design

Classification

Principle

Advantages

disadvantages

Indications

Contraindications

Radiation dose and safety precautions

diagnosis

Recent advances

Conclusion

references

INTRODUCTION

Computed tomography is one of the most frequently used

imaging modalities for jaw evaluation.

It is a radiographic technique that blends the concepts of thin

layer radiography (tomography) with computed synthesis of

image

HISTORY

1917- mathematical principle on which CT is based was first

presented by Radon ie a 3D image could be created from

using an infinite set of all of its 2D projections

1972- Godfrey Hounsfield announces first CT machine:

Computerised axial transverse imaging

1972- first clinical scanner in Atkinson Morley Hopsital,

London

1979-Sir Godfrey Hounsfield and Allen Cormack share Nobel

Prize for their pioneering work in invention

PRINCIPLES OF OPERATION

The source detector makes a single sweep/translation

across the patient, the internal structures of the body

attenuate x-rays according to mass density and effective

atomic number

similarly, a second and multiple translations are made

The projections formed are not displayed on the computer,

instead stored in digital format

Computer processing involves effective superimpositions of

each projection to reconstruct an image of anatomic

structures within the slice

IMAGING SYSTEM COMPONENTS

Gantry assembly:

Consists of an x ray tube, detector array, high voltage

generator, patient support and positioning couch and

mechanical support for both

Gantry can be tilted up to 30 degrees

X-ray tube/source :

X ray generator-400mA beam at nearly continuous beam

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X-ray tube-must operate at low tube current as well (100mA)

Anode heating capacity must be atleast 500 000-2 million

HU and it must be a rotating one to dissipate heat

Focal spot must be large-2mm

Detector array

Four-thousands detector array used

Previously-gas filled

Recent-scintillation solid state

The scintillation crystal photodiode convert light into

electronic signal, smaller and cheaper not requiring power

supply.

Crystals used are bismuth germanate, cesium iodide,

cadmium tungstate, special ceramics.

SD-high x ray detection efficency(90%) =reduced patient

dose, reduced examination time,

improved image quality

Collimation-reduces patient dose and limits scatter of

radiation thus improving image contrast.

Two collimators used ie pre patient and post patient

collimator.

Slip ring technology- electromechanical device allows

gantry to rotate continuously without interruption.

Computed tomography machine

All the CT systems use a similar three step process to

generate a CT image.

1)Scan or data acquisition

2)Reconstruction

3)Display

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3

IMAGE ACQUISITION

CT images are acquired in axial plane

Images are taken in succession : slices

Information from multiple images are reformated to produce

images in coronal,saggital, panoramic orientation

The matrix size of an image refers to number of discrete

picture elements: pixels

Pixels are two dimensional entities

Thickness of CT image applied to the slice, individual

elements are termed as volume elements : voxels

Volume of tissue in Voxel= pixel dimensions x slice width

A pixel cannot be manipulated in an image matrix, the area

of tissue being imaged can by adjusting the Field of View

(FOV) or diameter of reconstructed image

More detail can be captured by a smaller FOV than a larger

one

CT numbers or Hounsfield Units

The numeric data in each pixel is called CT number or HU

Corresponds the linear attenuation coefficient of a particular

tissue at a designated kilovoltage

range:-1000-+1000 where water is 0

Recent:-1000-+4000

IMAGING RECONSTRUCTION

Performed by the computer of the scanner

Different algorithms used: 1.Back projection/summation

reconstruction

2.Iterative reconstruction

3.Analytic reconstruction

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4

Back projection-one of the earliest methods, no longer used

-method of reconstruction of

superimpositioned images generated from different

projections

- Limitation: accentation of signals from

dense objects producing a star patterened defect

- simple test object containing 3 objects with

different attenuation values is scanned and that views

(attenuation measurements) are obtained at 3 angles

The attenuation measurements of each view are simply

divided evenly along the path of the ray; this process is

called back-projection.

The blurring can be reversed by a mathematic process

known as filtering

This reconstruction algorithm, known as filtered

backprojection (FBP), is efficient, yields excellent results,

and is still the algorithm of choice today for slice-by-slice CT

BP. Mathematic phantom image reconstructed without (A) and with (B)

filtering. FBP effectively reconstructs high-quality images.

A) Backprojection reconstruction for simple phantom containing 3 objects with

different attenuation values. (B) For each view, attenuation values are simply

divided evenly along their ray paths. Summing backprojected views from

several angles builds image. (C) Four views of phantom are summed.

Although this method is efficient, images reconstructed with backprojection

exhibit considerable blurriness.

Iterative method-not every area was imaged and

mathematical calculations could evaluate missing data

-did not take into account minute tissue

variations

Analytic method-uses complex mathematical calculations to

address minute variations in tissue density when data is

missing

-image accurate but time intensive

commonly used: Fourier analysis and filtered back projection

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5

The x-ray beam to be used was collimated down to a

narrow (pencil-width) beam of x-rays.

The size of the beam was 3 mm within the plane of the slice

and 13 mm wide perpendicular to the slice (along the axis of

the subject).

In fact, it is this beam width that typically specifies the slice

thickness to be imaged.

The x-ray tube is rigidly linked to an x-ray detector located

on the other side of the subject.

Together, the tube and the detector scan across the subject,

sweeping the narrow x-ray beam through the slice .

This linear transverse scanning motion of the tube and the

detector across the subject is referred to as a translation.

The combination of linear translation followed by

incremental rotation is called translate–rotate motion.

Data collection was accomplished with a single narrow

beam and a single sodium iodide (NaI) scintillation detector.

This arrangement (single detector and single narrow beam

with translate–rotate motion) is referred to as first-

generation CT geometry and required 5–6 min to complete

a scan.

CT arrangement. Axial slice through patient is swept out by narrow (pencil-width) x-ray

beam as linked x-ray tube–detector apparatus scans across patient in linear translation.

Translations are repeated at many angles. Thickness of narrow beam is equivalent to

slice thickness.

Lee W. Goldman. Principles of CT and CT Technology. J. Nucl. Med. Technol.September

2007 vol. 35 no. 3115-128

objective of CT image reconstruction is to determine how

much attenuation of the narrow x-ray beam occurs in each

voxel of the reconstruction matrix.

These calculated attenuation values are then represented as

gray levels in a 2-dimensional image of the slice.

The 2 voxel dimensions lying in the plane of the slice (X and

Y) are often referred to as pixels; however, the sizes of the

pixels in the displayed image (referred to as the image matrix)

are not necessarily the same as those in the reconstruction

matrix but rather may be interpolated from the reconstruction

matrix to meet the requirements of the display device or to

graphically enlarge (zoom) the image.

To carry out reconstruction, consider the row of voxels

through which a particular ray passes during data collection

Ni is the transmitted x-ray intensity for this ray measured by

the detector.

No is the x-ray intensity entering the subject (patient) for this

ray.

It can be shown that a derived measurement Xi can be related

to a simple sum of the attenuation values in the voxels along

the path of the ray; for the row of voxels, this relationship

isEq. 1where Xi = −ln(Ni/No) and ui =wiμi is the attenuation of

voxel i.

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Similarly, measurements for all rays at all positions and

angles can be expressed as sums of the attenuation values in

voxels through which each ray has passed.

In Hounsfield's scanner, No was directly measured by a

reference detector sampling the x-ray intensity exiting the x-

ray tube. Modern scanners determine No from routine

calibration scans.

For example, consider a simple 2-row by 2-column

reconstruction matrix .Views are collected at 4 angles, 0° (left

to right), 90° (top to bottom), 45° (diagonal), and 135°

(diagonal), and each measurement is expressed as the sum

of the voxel attenuation values along each ray.

ART. (A) ART algorithm for 4-voxel

“patient.” (B) Attenuation

measurements. (C) Starting

estimate is constructed by dividing

measurements from first view

equally along their ray paths. (D–F)

This estimate is iteratively adjusted

to match measurements for each

consecutive view, stopping when

transmission measurements

predicted by current estimate

match all actual measurements to

within some preset tolerance.

Algerbraic reconstruction technique iterate:sensitive to

quantum noise (quantum mottle) and could result in poor

image quality when transmitted intensities are low

No estimate that ART generates will ever match all

measurements exactly, because the measurements include

random errors.

GENERATIONS IN CT

First generation

The original device was a dedicated head scanner in which

the patient's head was recessed via a rubber membrane into

a water-filled box .

The device was designed such that the water-filled box

rotated (in 1° increments) along with the single-narrow-beam,

single-detector assembly, resulting in a fixed path length

through patient plus water for all rays and transmission

measurements.

The results obtained with this first clinical EMI scanner

(installed in September 1971) were presented at a British

radiologic society meeting in April 1972.

Water bath used: allowed Hounsfield to maximize the

accuracy of attenuation coefficient measurements.

a. Limitation of Dynamic Range: reduced the range of

intensities over which the detector needed to accurately

respond, thus allowing optimization of the detector sensitivity.

b. Beam-Hardening Correction: x-Rays produced in x-ray tubes

are mostly bremsstrahlung x-rays , cover a broad continuum

of energies (up to a maximum numerically equal to the x-ray

tube kilovoltage: polychromatic) .

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7

Beam hardening refers to a gradual increase in the effective

energy of polychromatic x-ray beams as they penetrate

deeper into attenuating materials.

Water bath was eliminated using a “bow-tie” filter through

which the beam passes when exiting the x-ray tube.

the filter (usually made of aluminum) is thicker where the

path through the patient is shorter (toward the edges),

effectively limiting the range of intensities reaching the

detector.

The filter prehardens the beam (i.e., it removes the lower-

energy x-rays), so that less hardening occurs in the patient.

The remainder of the beam-hardening correction is done with

software and periodically performed calibration scans of

uniform phantoms of various sizes.

REDUCING SCAN TIME: SECOND GENERATION OF CT

The first waterless full-body CT scanner was developed and

installed by Ledley et al. at Georgetown University in

February 1974 .

This device introduced several innovations now standard in

CT (table movement through the gantry, gantry angulation,

and a laser indicator to position slices) as well as a Fourier-

based reconstruction algorithm mathematically equivalent to

FBP (R.S. Ledley, personal communication) but still used

first-generation design, with scan times of 5–6 min.

As a result, body scans were unavoidably corrupted by

patient motion.

Second-generation CT used multiple narrow beams (3) and

multiple detectors (3) and, as in the first generation, used

rotate–translate motion.

It may seem at first that second-generation CT accelerated

data collection via simultaneous measurements at each point

along a translation.

In fact, if the set of rays measured by each detector is

considered , it can be seen that the detectors actually acquire

their own separate, complete views at different angles

Second-generation data collection. (A) Transmissions of multiple narrow

beams (3, in this case) were simultaneously acquired by multiple

detectors during each translation. (B–D) Small angle between narrow

beams allowed each detector to acquire complete separate view at

different angle. Number of required translations was correspondingly

reduced by factor of 1/(number of detectors).

THIRD GENERATION OF CT

Faster scans required the elimination of translation motion

and the use of smoother and simpler pure rotational motion.

This goal is accomplished by widening the x-ray beam into a

fanbeam encompassing the entire patient width and using an

array of detectors to intercept the beam .

The detector array is rigidly linked to the x-ray tube, so that

both the tube and the detectors rotate together around the

patient (a motion referred to as rotation–rotation).

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8

Many detectors are used to allow a sufficient number of

measurements to be made across the scan circle.

This design, characterized by linked tube–detector arrays

undergoing only rotational motion, is known as third-

generation geometry.

The early third-generation CT scanners, installed in late

1975, could scan in less than 5 s; current designs can scan

as quickly as one third of a second for cardiac applications.Third-generation geometry. Time-consuming and mechanically complex translation

motion was eliminated by opening x-rays into fanbeam. Large array of detectors

measured data across width of fan. Tube and detectors were rigidly linked and

underwent single rotational motion.

each detector measures rays passing only at a specific

distance from the center of rotation, depending on the

location of the detector in the array

Any error or drift in the calibration of a detector relative to the

other detectors is back projected along these ray paths and

reinforced along a ring where they cross

Ring artifacts may result from detector inaccuracies as small

as 0.1%.

Third-generation CT was highly successful and remains the

basic geometry of most CT scanners manufactured today.

FOURTH-GENERATION SCANNERS

By 1976, 1-s scans were achieved with a design

incorporating a large stationary ring of detectors, with the x-

ray tube alone rotating around the patient

Fourth-generation

scan geometry.

Fixed detector ring

in original design

was quite large,

because tube

rotated inside ring.

Later designs

moved tube

outside ring and

tilted ring out of

way of x-ray beam

as x-ray tube

swept by.

the set of rays measured by one detector as the x-ray tube

sweeps across its field of view is analogous to one third-

generation fan beam view but with the roles of tube and

detectors reversed

Each fourth-generation detector collects a complete fanbeam

view

It can measure rays at any distance from the center of

rotation and can be dynamically calibrated before it passes

into the patient's shadow, so that ring artifacts are not a

problem.

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9

Drawbacks of early fourth-generation CT :Because the tube

rotated inside the detector ring, a large ring diameter (170–

180 cm) was needed to maintain acceptable tube–skin

distances.

On the other hand, acceptable spatial resolution limited

detector apertures to ∼4 mm.

Consequently, even allowing for ∼10% space between

detectors, 1,200 or more detectors were needed to fill the

ring, but cost considerations initially limited the number to

600.

The result was gaps between detectors and low geometric

dose efficiency (<50%),

A later, alternate design used a smaller ring placed closer to

the patient, with the tube rotating outside the ring; during tube

rotation, the part of the ring between the tube and the patient

would tilt out of the way of the x-ray beam (the peculiar

wobbling motion of the ring was called nutation).

Another disadvantage of fourth-generation designs was

scatter: scatter-absorbing septa could not be used

fourth-generation CT was not more (or less) advanced than

third-generation CT

ELECTRON-BEAM CT (EBCT)

Subsecond scans would burden x-ray tubes; because

approximately 250 mAs (i.e., tube current in milliamps times

scan time in seconds) per slice are required for acceptable

body CT, a 0.25-s scan would require sustaining 1,000 mA.

However, cardiac CT requires ultrafast scans (<50 ms) to

freeze cardiac motion, a goal unreachable with conventional

scanning even today

Various ideas were proposed including a novel CT design

that had no moving parts and that was capable of performing

complete scans in as little as 10–20 ms.

The idea behind ultrafast CT is a large, bell-shaped x-ray

tube.

An electron stream emitted from the cathode is focused into a

narrow beam and electronically deflected to impinge on a

small focal spot on an annular tungsten target anode, from

which x-rays are then produced.

The electron beam (and consequently the focal spot) is then

electronically swept along all (or part) of the 360°

circumference of the target.

Wherever along the annular target the electron beam

impinges, x-rays are generated and collimated into a

fanbeam .The concept is known as EBCT.

EBCT was limited to a niche market (cardiac screening),

mostly because image quality for general scanning was lower

than that of conventional CT (because of low mAs values)

and because of higher equipment costs.

SLIP RING SCANNERS AND HELICAL CT

CT examination times were dominated by interscan delays.

After each 360° rotation, cables connecting rotating

components (x-ray tube and, if third generation, detectors) to

the rest of the gantry required that rotation stop and reverse

direction.

Scanning, braking, and reversal required at least 8–10 s, of

which only 1–2 were spent acquiring data.

The result was poor temporal resolution (for dynamic

contrast enhancement studies) and long procedure times.

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A slip ring passes electrical power to the rotating components (e.g., x-ray tube and detectors) without fixed connections.

Similarly, a slip ring is a drum or annulus with grooves along which electrical contactor brushes slide

A slip ring allows the complete elimination of interscandelays, except for the time required to move the table to the next slice position.

Rapid table movements may introduce “tissue jiggle” motion artifacts into the images.

There is continuous rotation and continuous acquisition of

data as the table (patient) is smoothly moved though the

gantry; the resulting trajectory of the tube and detectors

relative to the patient traces out a helical or spiral path

This powerful concept, referred to synonymously as helical

CT or spiral CT, allows for rapid scans of entire z-axis regions

of interest, in some cases within a single breath hold.

So significant were improvements in body CT quality and

throughput that helical scanning became the de facto

standard of care for body CT by the mid-1990's.

Helical CT sample spacing and interpolation. If data for desired slice of thickness d

(dark gray bar in figure) are interpolated between equivalent rays from adjacent

helical rotations (loops) with pitch of 1.5, samples will be 1.5 d apart along z-axis

(e.g., 10.5 mm apart for 7-mm thickness). Larger spacing means greater chance

that interpolated estimate is in error. If 180°-opposed rays are included,

measurements average half as far apart (and are more likely to actually lie within

slice). det = detector.

The speed with which the table slides through the gantry is

relative to the rotation time and slice thicknesses being

acquired.

This aspect is referred to as the helical pitch and is defined

as the table movement per rotation divided by the slice

thickness.

Eg: if the slice thickness is 10 mm and the table moves 10

mm during one tube rotation, then the pitch = 10/10, or 1.0;

slice interpolation

if the helix represents the path of the detectors, then the

detectors are above the slice plane at 0° but below the slice

plane 180° later .

Only a small number of measurements actually lie exactly

within the plane of the slice.

To allow image reconstruction, it is necessary to estimate

from the measurements lying above and below the slice what

the measurements would have been within the slice. The

process known as interpolation is used to make these

estimates.

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11

It is distinctly possible, however, that the anatomy actually

lying between the 2 measurements differs significantly from

that at which the measurements are obtained.

If so, then the estimate may be significantly in error, leading

to image misrepresentation or image artifacts.

As a rule, the farther apart interpolated data points are, the

greater the chance of error.

The process just described is called 360° interpolation,

because data are interpolated between measurements

obtained 360° (one full rotation) apart by the same detector

At some point during each 360° rotation, every ray is

measured twice, but with the x-rays traveling in opposite

directions (i.e., 180° apart).

These 180°-opposed rays are closer together—and thus

allow fewer chances for interpolation errors—than those that

are 360° apart.

The process that makes use of these rays is known as 180°

interpolation and is the one that is generally used.

The selection of pitch is essentially a trade-off between

patient coverage and accuracy; larger pitches allow more

coverage of a patient per unit of time (or per breath hold), but

slice data must be interpolated between points that are

farther apart, allowing more chances for errors.

Pitches of between 1 and 1.5 are commonly used.

Pitches of greater than 1.5 are uncommon, whereas pitches

of greater than 2 generally yield unacceptable results and are

not used.

Pitches of less than 1 are not used in single-slice helical CT

because of the double irradiation mentioned earlier but are

common in multislice CT.

The definition of pitch described earlier (table movement per

rotation divided by the slice thickness) has been altered to

accommodate multislice CT.

The definition has been updated by replacing slice thickness

in the denominator with the z-axis x-ray beam width.

CT FLUOROSCOPY

The potential for the high sensitivity of CT to guide

percutaneous aspirations and biopsies had long been

recognized.

With continuous, dynamic scanning being made possible by

slip ring CT, real-time CT fluoroscopy became feasible.

A slip ring scanner is modified to allow real-time tableside

image viewing and table positioning via foot pedal–controlled

acquisitions and joy stick–controlled table positioning.

Because a slip ring scanner can continuously acquire views at a fixed z-axis, temporal resolution can be considerably better than expected on the basis of rotation speed; images can be updated several times per second by continually adding new data to the reconstruction dataset and dropping the oldest data.

For example, suppose a first image is displayed after one full 360° rotation with a 1-s rotation time.

After another 1/6 s, another 60° of views has been acquired and is added to the dataset, and the original 60° of data is dropped.

A new image is displayed on the basis of the latest 360° (in this case, from data collected between 60° and 420°) but is 1/6 s later than the first image.

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After another 1/6 s, the image is again updated, from data

collected between 120° and 480°, and so forth. Images are

thus updated at 6 frames per second.

CT fluoroscopy has proven valuable for interventional

procedures but creates the potential for significant radiation

doses if too many images are acquired at a given location .

To minimize radiation exposure, a recent trend has been to

replace continuous acquisition with a series of discrete,

rapidly acquired images to guide biopsies.

Image characteristics

Image receptor in CT have a linear response to exposure,

hence images of extreme intensity maybe visualised

Resolution:

Two components of resolution: spatial and contrast

resolution

Spatial resolution CT scanners: a.15lp/cm

b.can be calculated if the

number of detctors in known

c. two detectors are

required to capture a line pair

Limited by:a. focal spot

b. spacing of detector array

c. magnification factor

CT number of a pixel=average of linear co efficent of all

tissues captured in that pixel

CT number=K(mu voxel x mu water)/ mu water where

K=1000 and mu water =0

a material must differ from its surroundings by at least 1% to

ensure a different gray level.

Tissues of most common interest in CT generally lie in the

CT number range of −1000 to +1000

Partial volume averaging: Edge of a particular structure,

starts in the middle of the pixel, edge is obscured

IMAGE ENHANCEMENTS

Three dimensional renderings can be used to show only the

surface of the object (surface rendering) or the relationship

of the object to surrounding structure (volume rendering)

Windowing: ability to view a CT image using different density

parameters

- Allows selection of range of densities to be

viewed (window level) and number of gray levels to be

viewed ( window width)

THREE DIMENSIONAL CT IMAGE RENDERING SYSTEM

Diagnostic image data format standards: DICOM

Improves possibility of use of independent computers in 3D

imaging

The images can be rotated, translated and segmented and

displayed in different positions adding important

complimentary information about complex anatomy in

maxillofacial region.

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3D CT maging techniques: a. Multi-planar reformatting and

Dental MPR

b. Shaded surface display

c. Volume rendering

d. Maximum Intensity Projection

e. Model projection and virtual

reality

Multi-planar reformatting and Dental MPR

Proposed by Glenn et al in 1975

Displays slices in any direction in the orthogonal and

curvilinear plane

Provide contiguous cross-sectional image of jaws and dental

arch

Eg: Dental CT, Dentascan,

Shaded surface display

For examination of surface of a structure such as bone, teeth

etc

To visualize a selected structure: Threshold must be defined

to separate soft and hard tissue using CT number (HU)

Skin: <300HU

Bone:150-200HU

Teeth:<1000HU Seen in 3d as the alveolar bone has lower

HU than dentin

Faster speed: Allows interactive repositioning and

manipulation of images rapidly (real time)

Volume rendering

Multiple thresholds and transparencies selected

Sufficient selection of thresholds, results in a volumerendered 3D image

Advantage: inner features of 3D structure can be seen

Inner hard and soft tissue structures are visible becauseeach voxel has 8-12 bits of density value

In a 12 bit image, voxel density value corresponds to HU

Opacity of structures vary from 0%-100%

High flexibilty volume rendering allows modification asconventional panoramic or cephalograms.

Maximum intensity projection

Intensity of each voxel is the maximum intensity encountered along a line from the viewers eye as it traverses the volume

Used to create angiographic images from CT : pulse sequences used in data collection shows maximum intensity as contrast medium is injected for higher HU

Used is1. neuro radiology

2.congenital and developmental abnormalities

3. trauma.

4.intra cranial soft tissue structures

5.shaded surface display images from spiral CT data allow for a more simplified display of pathology for surgical planning

TACT – TUNED APERTURE COMPUTED TOMOGRAPHY

It was first developed by Webber et al.

three dimensional (3D) radiographic data acquisition scheme

The method is based on optical aperture theory, which

extends and completely generalizes the better known

laminographic process termed tomosynthesis.

It does so by eliminating most of the constraints underlying

tomosynthetic image acquisition, projection geometry and

data management, through the application of simple back

projection algorithms.

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14

The technology can accommodate patient movement

between exposures with no appreciable effect on the image

quality or projection accuracy underlying the resulting 3D

display.

TACT maps all incrementally obtained projection data

(source images) into a single 3-D matrix even when the

shape of the equivalent sampling aperture is unknown.

Thus TACT

1) Produces meaningful 3D reconstructions from optical

systems having any number of different aperture functions.

2) Any aperture can be approximated by summation of finite

number of appropriately distributed point apertures.

Tomosynthesis is similar to tomography, wherein

tomography is a single image is produced continuously

In tomosynthesis, multiple discrete images are produced,

each corresponding to a different relative position of the

source and film plane.

This results in system that is characterized by multiple x-ray

projections, each involving a different projection angle.

By analyzing multiple projections simultaneously in

appropriate registration, it can be shown that the resulting

data contain 3D information.

It carries the same radiation risks as a single conventional

film when exposed using comparable collination, but would

yield reconstructions exhibiting significantly less quantum

mottle than film image.

PET-CT

PET – CT has a single table with a combined gantry of CT &

PET.

In one single study, high resolution CT of desired organ is

obtained with superimposition of PET images on underlying

anatomical data, leading to unparalleled imaging acquisition.

PET – CT, a unique combination of cross sectorial details

provided by CT and metabolic information obtained by PET

has revolutionized cancer detection work.

CT perfusion studies have been useful is evaluating viable

tumor tissue, which normally shows increased perfusion.

CT-PET has been found invaluable is accurate localization of

very small areas of increased traced activity

Advantageous in separating normal structures with high

metabolic activity from abnormal high activity, without the

need to change the position of the patient between the

scans.

In a PET/CT scanner, it is possible to perform attenuation

correction by means of CT, because CT image is a

transmission image of the body.

SPECT [SINGLE PHOTON EMISSION COMPUTED

TOMOGRAPHY

A technique for gathering and displaying nuclear medicine

images.

Its operation involves a gamma camera that rotates around

the patient, generating circumferential projections.

Axial tomographic slices approximately 6.5 mm apart are

then computed in similar fashion to computed tomography

scans for x-ray images.

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15

SPECT imaging of skull base in patients with skull base

disease is more sensitive than planar imaging and can

provide anatomic location and may be useful in patients with

negative CT scan.

SPECT scanning has been used to assess condylar activity

and comparisons have been made with planar imaging.

SPECT imaging describes a process that creates

tomographic images from emitted photons, improving spatial

resolution over planar images.

Dual isotope bone scan : White blood cell and bone is

scanned after labelling

TC-MDP (Technetium 99 m methylene diphosphonate) is a

common agent used in bone scans, with photon energy of

140 KeV.

Indium emits photons of 173 & 247 KeV and gamma camera

can be set to photopeaks of 140 & 247 KeV, allowing

simultaneous co-registered TcM and in data sets to be

acquired.

Accumulation of in labeled WBC’s is an area of increased

hyperemia and bone turnover is strong evidence for

osteomyelitis.

Conversely Tc M-MDP uptake without In WBC accumulation

suggests bone remodeling without infection.

CONE BEAM COMPUTED TOMOGRAPHY

CBCT is alternative imaging technology for acquiring 3D

data for diagnostic tasks like implant treatment planning.

Cone beam CT has advantages of high resolution and low

dose radiation of the skin.

Dental 3D-CT clearly demonstrates lesions in the bone.

Information about the relationship between lesions and

proximal anatomical structures is useful for minor oral

surgery.

Resorption of bone by the disease, position of the

mandibular canal and location of the maxillary antrum are

depicted more clearly on Dental 3DCT than on conventional

radiographs

The Dental 3D-CT apparatus provides the thinnest slice

image available in clinical use.

PATIENT EXPOSURE TO RADIATION

Dependant: Area being imaged

Number of slices

Thickness of slice

Kilo volt peak used – inversely proportional

Effective dose for head scan: 2-4mSv

CT dose index: Addresses the location of scan and thickness

of slice

Multiple scan average dose: Determines patient exposure

taking scatter radiation into consideration as well

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16

In spiral CT: Pitch is to be considered –inversely proportional

to dose

For a single CT scan, almost all primary radiation is confined

to a thin cross section, with entrance beams only on the

narrow strip of skin constituting the edge of this section.

dose is received by tissues outside the nominal image

section because of a combination of beam divergence,

penumbra, and scattered radiation.

Therefore, when adjacent sections are scanned, the dose to

any one section is increased by contributions from other

sections.

The magnitude of the increase depends on the number of

sections, the separation or gap between the sections, and

the particular characteristics of the single-scan dose profile.

The magnitude of the dose and the precise shape of the

various dose profiles depend strongly on both the details of

the scanner design and the choice of operating techniques

for a given series of scans

Computed

Tomography (CT)-

Head

2mSv 8 months

Computed

Tomography (CT)-

Head, repeated

with and without

contrast material

4mSv 16months

Intraoral X-ray 0.005 mSv 1 day

2017 Radiological Society of North America, Inc.

Positron Emission

Tomography –

Computed

Tomography

(PET/CT)

25 mSv 8 years

Radiation dose reduction in computed tomography: techniques and future perspective.

Imaging Med. Author manuscript; available in PMC 2012 Feb 3.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3271708/

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17

ARTIFACTS

Ring artifact is caused by a miscalibrated or defective detector element, which results in rings centered on the center of rotation. This can often be fixed by recalibrating the detector.

Noise • Poisson noise is due to the statistical error of low photon counts, and results in random thin bright and dark streaks that appear preferentially along the direction of greatest attenuation.

This can be reduced using iterative reconstruction, or by combining data from multiple scans. Noise reduction techniques enable diagnostic scans at a much lower radiation dose.

Ring artifact

Noise artifact

Model-based iterative reconstruction (MBIR), for example,

attempts to smooth out the noise while preserving edges,

resulting in a plastic appearance, where there are small

clusters of pixels with similar Hounsfield units.

Beam hardening and scatter • both produce dark streaks

between two high attenutation objects (such as metal or

bone), with surrounding bright streaks.

These can be reduced using iterative reconstruction.

Metal artifact • Metal streak artifacts are caused by multiple

mechanisms, including beam hardening, scatter, Poisson

noise, motion, and edge effects.

The Metal Deletion Technique (MDT) is an iterative

technique that reduces artifacts due to all of these

mechanisms.

Out of field “artifact” • are due to a suboptimal

reconstruction algorithm, and can be fixed using a better

algorithm.

Images can then be acquired using a field of view that is

much smaller than the object being scanned, thus reducing

the radiation dose.

Metal artifact

Out of field artifact

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ADVANTAGES

Contrast resolution is comparatively high:a. 5000 CT

numbers or gray levels in a pixel

b.Density

differences of less than 0.5% can be detected

c.superior low

contrast resolution

Can be electronically processed without altering original

image

Image can be viewed in different orientations in different

parameters

A three dimensional rendering of a structure or an image can

also be reconstructed from original data

A fundamental advantage of the CT process was the

potential to (almost) completely eliminate scatter:

a. because the CT beam is not more than 1 cm wide in the Z

direction, compared with up to 43 cm (17 in.) in radiography.

b. Eliminated by use of the equivalent of a scatter removal

grid; x-ray-absorbing septa placed at the boundaries

between detectors and aimed at the focal spot allow primary

x-rays to pass while stopping most scattered x-rays before

they enter the detectors

Scatter with CT fanbeam. Use of fanbeam increases scatter production at any

moment (more tissue is irradiated), and more scatter can reach detectors. Amount

of scatter produced is still much smaller than that in radiography because fanbeam

is only ∼1 cm thick. Scatter can be eliminated in third-generation CT with scatter

removal septa, which act like nearly ideal grid. (A) First-generation CT. (B) Third-

generation CT.

X-ray beam is limited to tissue section under study and

attenuation by tissues in adjacent areas do not produce

image degradation.

The x-ray detectors used in CT are highly efficient collecting

close to 100% of incident photons compared to conventional

X-ray film screen combinations, which collect 50% or less of

incident photons.

Inherent noise in CT detection systems is < 0.5%

Since image is recorded electronically, it can be displayed

with wide range of contrast setting without the need to repeat

scan.

No magnification errors because of geometric distortions.

No superimposition of image, as each tomogram represents

a cross section through the area examined.

Details of soft tissue are preserved, allowing the radiologist

to evaluate anatomy of soft tissues and in some cases

differentiate between specific tissue densities like blood,

tumor or calcified tissue.

The image that is produced is formulated by the computer, so areas of interest may be selectively viewed and enlarged by using the correct computer program.

As with conventional tomograms, axial, coronal and saggittalslices may be obtained, allowing the diagnostician to view the object from all 3-dimensions.

Capability of expansion, formation of 3-D images can be displayed either by holography or by shading techniques.

Disturbances of normal anatomic arrangement of muscles and fat planes, neurovascular bundles and fine bony architecture of face and base of the skull are clearly seen with CT. Thus helpful in identifying and localizing traumatic injuries, infection and neoplasia.

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DISADVANTAGES

Spatial resolution is poor in comparison to plain films

High contrast resolution in CT is poor incomparison to plain

radiographs

Artifacts due to patient motion

Cost

Radiation dose

USES:

1.It shows anatomically precise location of lesion and

extension

2.CT is of unique value in delineating those lesions that have

both osseous and soft tissue extension.

3.Involvement of infratemporal, parapharyngeal spaces, oral

cavity, skull base and other adjacent structures can be

readily determined.

4.It helps in distinguishing between benign and malignant

lesions.

5.It helps to assess the extent of infection in maxillofacial

region

6.CT can image diseases and s. tissue involvement of orbits

and brain

7.I.V. contrast material, which enhances characteristic lesions

and evaluates the vascularity of the lesion.

8.High resolution CT improves staging of malignant tumors

9.CT scans help to document the results of irradiation and

chemotherapy

10.The muscles of mastication can be seen with CT scanning.

11.In patients with dental infections that extend into

parapharyngeal spaces, CT with soft tissue enhancement is

valuable in assessing displacement of parapharyngeal soft

tissues and secondary impairment of airway that soft tissue

displacement creates. Areas of localization of pus can be

identified in this manner.

12.Evaluation of jaws of patients who are candidates for dental

implants.

LIMITATIONS

1.CT scan equipment is sophisticated, costly and expensive to

maintain. Number of patients that can be scanned per

standard work day is limited and these facilities are difficult to

install in settings of rural India.

2.CT scan is currently available only isnaxial plane for direct

coronal scanning of the head. This limitation can be partially

overcome by section rearrangement programmes.

3.CT scan times are relatively long compared to fraction of a

second exposure used in projection radiography. Motion of

the structures during scanning will degrade the image.

4.Inaccuracies in CT image pixels are produced by special

artifacts due to high contrast discontinuities and peculiar

curvilinear anatomic areas.

5.Patient must be completely still or may lead to artifacts due to

patient motion.

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DENTAL APPLICATIONS IN COMPUTED TOMOGRAPHY

1.Benign and malignant lesions of oral and maxillofacial

regions

2.Preplanning for surgical procedures

3.Delineation of contiguous vascular structures by CT

4.Bone destruction, soft tissue extension of neoplastic

disorders seen as differences in density of different

materials.

5.Orofacial infections, their extent and spread.

6.Intracranial extension of infective process in maxillofacial region.

7.Maxillofacial fractures – orbital, basilar skull fractures

8.Craniofacial anomalies like Aperts& Crouzon’s syndrome can be visualized, along with planning for surgical correction of such anomalies.

9.Used in diagnosing displaced menisci, TMJ disorders

10.Cemento osseous lesions

11.Cleft palate patients

12.Head Injuries

CT IN DENTISTRY:

CT is the most sensitive imaging modality for bony changes

in the jaws, the changes may be due to periosteal new bone

formation or destruction of the cortex or changes in bony

trabeculae or mineral density or due to any erosions in the

bone.

CT has been reported to be superior to conventional

radiography.

The patterns on CT were grouped into (4) categories as:

1.no destruction

2.point destruction, where there is small defect in cortex with

or without defect is trabecular bone

3.gross destruction which is continuous with large defect in

trabecular bone

4.permeative destruction in which numerous small defects

are present in the cortex with large defect or rarefaction of

trabecular bone.

Also determination of presence or absence of erosion is the

cortices of intact jaws can be done by CT, which may reveal

periapical rarefying osteitis.

High resolution CT was used in a study by Marmay et al in

26 patients, where the margin of the cortex and periphery of

the osteitic lesion could clearly be identified on cross-

sectional reconstruction.

CT is the only non-invasive pre-operative method to obtain

information on the degree of mineralization of bone as

distinct from cortex.

It is also used pre-operatively to evaluate jaw bone volume

and to make measurements of bone height and width.

CT can be used in imaging patients with complex and

challenging cleft palate , for precisely outlining cleftal bony

involvement, discovering spontaneous bone bridging,

measuring residual thickness of alveolar bony segments and

describing deviation of bony palatal shelves and their bony

excresences.

CT measurements evaluate bone width changes and gives

accurate measurements of bone thickness of 0.5 mm.

They can demonstrate changes in alveolar bone as a result

of incisor refraction in-patients with bimaxillary protrusion.

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21

CT shows bone graft in 3 Dimensions providing precise

evaluation of bone volumes.

HR-CT is widely available for delineation of fine structures,

the resolution and contrast are comparable for most

scanners. It allows periodontal bone structures to be imaged

in contiguous slices with no overlap

HRCT is used in diagnosis of periodontal bone structures,

especially in imaging both normal buccal and lingual alveolar

bone and artificial dehiscences by means of an in vitro

quantitative radiological and histological comparison.

LYMPH NODES OF NECK

Imaging is indispensable in the evaluation of cervical

lymphadenopathy.

Imaging criteria for lymphadenopathy is based on nodal size,

internal heterogenicity, presence of clusters , shape and

associated findings.

Internal lymph node heterogenicity is one of the most reliable

criteria for recognizing lymphadenopathy .

Normal cervical nodes appear homogenous and of soft tissue

attenuation or intensity on imaging

Nodal homogenicity does not exclude metastases because

homogenous nodes may harbor non-necrotic tumor cells.

Nodes involved with lymphoma are typically homogenous.

Enhanced CT is better in establishing nodal necrosis.

Helical CT is also used to differentiate malignant from

reactive nodes by calculating the ratio of maximal longitudinal

to maximal axial diameter of enlarged nodes.

Nodes with ratios <2 and nearly spherical in shape are more

likely malignant than those with ratios of 2 or more, which are

more likely benign.

Nodes with ratios <2 and nearly spherical in shape are more

likely malignant than those with ratios of 2 or more, which are

more likely benign.

Calcifications of lymph nodes also seen in CT:

granulomatous diseases such as tuberculosis, previously

radiated neoplastic nodes and metastatic thyroid carcinoma.

Imaging is useful in identifying the location of the occult

primary neoplasm, suggesting a possible biopsy site, and

assessing the extent of the disease.

subtle asymmetries in the oral , pharyngeal and laryngeal mucosa on CT in order to direct biopsies of otherwise clinically detectable abnormalities.

Recently , 2 [ florine – 18] fluoro – 2- deoxy – D- glucose [ FDG] single photon emission computed tomography [ SPECT] has yielded promising results as a adjunct to conventional cross – sectional imaging in evaluating the occult malignancy.

CT findings associated with nodal involvement by both inflammatory and neoplastic processes. These findings range from multiple areas of increased density on non contrast enhanced or filling defects on contrast enhanced CT studies of the parotid to enlarged non- necrotic to cystic appearing nodes with low – density centers representing necrosis with loss of both specific organ architecture and adjacent fascialplanes.

The presence of 3 or more ill – defined , contiguous lymph

nodes measuring between 8 and 15 mm is abnormal

likewise, the presence of low density centers ( 10 – 18

hounsefield units) in any lymph node regardless of size or

peripheral enhancement is abnormal since the low density

centers represents central necrosis and can be seen in

metastatic, inflammatory and lymphomatous lymph nodes

Inflammatory and neoplastic lymph nodes frequently exhibit

ring enhancement following intravenous contrast

administration.

Nodal necrosis may be mimicked by lipid metaplasia which

represents fatty degeneration, secondary to inflammation or

irradiation fatty change and abscess formation generally

occur at periphery of node.

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22

Nodal lymphomas often present as bulky masses with

smooth margins of peripheral enhancement

Metastatic lymph nodes often demonstrate peripheral

enhancement, which is of uniform thickness and density

Presence of thick, irregular zone of peripheral enhancement

around necrotic centers is indicative of node involved by

inflammation process as in tuberculosis.

Stevens and associates have described a system of nodal

classification based on CT findings as well as size and

location.

CT OF PARANASAL SINUS AND ADJACENT STRUCTURES

Computed tomographic studies should be performed in axial plane parallel to the inferior orbital meatal [IOM] plane in continous increments of 5mm.

The scan should also be obtained when the possibility exists that volume averaging may occur in segment of bone parallel to the CT scan plane, resulting in suboptimal demonstration of an area.

All CT sections should be imaged using both bone and soft tissue windows.

PNS and nasal cavity tumors are usually homogenous on CT, although foci of hemorrhage/ necrosis can be seen.

Approximately 5 or 6 axial images, beginning at the alveolar

ridge and extending through the top of the frontal sinus, can

effectively produce 2 images through each sinus in axial

plane in 15 mins. of room time and 1-2 mins. of scan time.

Because of ability of CT to identify low – contrast changes , it

can be used to differentiate between fluid levels and soft

tissues in sinuses.

Intravenous contrasts should be used to evaluate a known

or suspected neoplasm.

The coronal plane is best for demonstrating anatomy of ostimeatalunit.

On axial CT sections, loss of retro antral or buccal fat pad, located adjacent to the lateral wall of the sinus can occur as a result of transmural extension of inflammatory or neoplastic process involving sinus.

Role of imaging in Paranasal Sinus:

1. Diagnosis.

2. Differentiation of tumor from chronic inflammatory tissue.

3. Tumor mapping

4. Staging- TNM classification, demonstration of direct spread and nodal metastasis.

5. Post treatment assessment

6. Detection of recurrence.

CT OF TEMPOROMANDIBULAR JOINT

CT for evaluation of TMJ was introduced by Wegener and

colleagues.

CT provides excellent imaging of the bony components of

temporomandibular joint.

The ability to image the articular disk is inadequate using CT

because of poor contrast resolution.

The selection of imaging modality for TMJ must be based on

structures about which the clinician needs to acquire

information .

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23

Using numerous axial plane scannings, it is possible to

reconstruct sections in the paramedian plane

eg :- for lateral depiction of TMJ: The paramedian plane of

TMJ is positioned in the tipped gantry in such a way that the

plane is positioned like an axial projection.

Also patient can be repositioned in gantry aligning saggital

plane parallel to scanning beams projections.

The result is lateral and sharply depicted scan that can

display the disc in atleast two dimensions if the soft tissue

window is selected.

Useful information can be obtained in TMJ ankylosis with 3-

D reconstruction as it readily demonstrates severity of

ankylosis and the amount of destruction and deformity of the

joint.

Additionally, 3D reconstructions in post traumatic patients

may be helpful in determining the amount of malalignment of

mandibular condyles, especially when compared with normal

contralateral side .

Prosthetic joints also may be fabricated from preoperative

3D images.

IMAGING OF SALIVARY GLANDS AND

PERIGLANDULAR REGIONS

Diagnostic imaging has assumed a central role in the

evaluation of host of abnormalities involving the salivary

gland.

Parenchymal lesions usually present as focal masses, best

evaluated by CT.

They provide excellent soft tissue details and differentiate

between specific tissue densities like fat, blood, tumor or

calcified tissues that show not only the lesions, but the

involvement of adjacent structures.

Axial CT examination – the relationship of parotid mass to

facial nerve can be inferred by noting the relationship of the

mass to retromandibular vein, also helps the surgeon in

planning the surgical approach to be used to minimize

chances of facial nerve injury.

CT can readily differentiate between intraglandular and

extraglandular masses and also to perform fine needle

aspiration biopsies of both masses for histologic or cytologic

diagnosis.

Contrast enhanced CT studies are especially useful in

evaluating abscess formation, because the hypervascular

wall of abscess will show characteristic enhancement.

The quantification of CT number is important for the

evaluation of inflammatory diseases, which are associated

with higher than normal CT numbers.

Ida & Honda reported that CT numbers of normal salivary

gland increases with age.

CT sialography is much more sensitive in differentiation of

extrinsic and intrinsic glandular lesions

combining sialography with CT, only small amounts of dilute

water soluble contrast agent are needed to demonstrate

intraglandular ducts, greatly decreasing risk of sialdenitis.

CONCLUSION

In the last few years, CT has significantly increased its diagnostic capabilities.

The development of spiral CT was central to the advancement of CT as a discipline.

With the rapid advancements in technology, the CT technologist has an increased responsibility to understand contrast dynamics and the new spiral scan parameters of pitch, collimation, scan timing and table speed.

Knowledge of the limitations of CT scanning in the head and neck region is also necessary

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24

Advances in computing power and design have produced

workstations that can generate 3- dimensional models in 30

secs or less, rotate the models along any axis and display

the models with varying parameters.

Because of CT’s superb diagnostic information and cost-

effectiveness, this imaging modality will continue to be a

highly respected diagnostic tool.

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Oral MaxillofacSurgClin N Am 2001; 13(4): WB Saunders

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• Ida M, Tetsumura A, Kurabayashi T, Sasaki T. Periosteal

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