431 Pds Practical Manual

7/31/2019 431 Pds Practical Manual

1/79

KING SAUD UNIVERSITY

College of Dentistry

Department of Preventive Dental Sciences

DIVISION OF ORTHODONTICS

431 PDS

PRACTICAL MANUAL

Part I

Prepared by:

Dr. Eman Al-Kofide

Dr. Hoda Al-Kawari

Dr. Sahar Al-Barakati

Dr. Hana Al-Balbeesi


2/79

2

Table of Contents

Topic

I. Introduction

II. Classification of Malocclusion

1. Normal Occlusion2. Malocclusion3. Class I Malocclusion4. Class II Malocclusion:

a. Class II div. 1b. Class II div. 2

5. Class III Malocclusion

III. Radiographs:

Orthopantomographs Occlusal Films Hand and Wrist Radiographs Cephalometrics

IV. Model Analysis:

1. Arch Perimeter Analysis: Moyers Analysis2. Arch Length Analysis: Nance Analysis


3/79

3

3. Tooth Size Discrepancy: Bolton Analysis

V. Orthodontic Appliances

VI. References


4/79

4

I. Introduction

Orthodontics is one of the most oldest branch in Dental Science.

Orthodontics (Ortho = Straight, Dontic = Teeth), is that branch of dental

science concerned with genetic variation, development and growth of facial

form. It is also concerned with the manner in which these factors affect the

occlusion of the teeth and the function of associated organs. Therefore we

are not only concerned with straightening of the teeth, but also of the

growth, development and function of the total orofacial complex.

The lecture series of this course will deal with the above-mentioned aspects

of orthodontics in more detail. The laboratory session of this course will

teach the student the technical part of Orthodontics.

The purpose of this manual is to introduce to the student the practical part of

this course in a more simplified and understandable manner. Itwill cover the

basics of Orthodontics from Classification of Malocclusion to Radiology in

Orthodontics. The main objective of this part is to acquaint the student with

proper Diagnosis in Orthodontics.

This manual will aid the student during the study of the technical part of

orthodontics. It is not considered a replacement of the required textbooks

for the course, but as an adjunct to help the student during the laboratorysession.


5/79

5

II. Classification of Malocclusion

1. Normal Occlusion

Occlusion is considered to be normal when the dental arches are in

correct alignment, with all the teeth in anatomically correct contact

and in physiologically optimal occlusion with the corresponding teeth

in the opposite dental arch.

The development of normal occlusion passes through several

continuous stages from birth to the development of the permanent

dentition. The deciduous dentition begins to appear at around the age

of 6 months with the eruption of the lower central incisors. The

deciduous teeth are usually complete by the age of 2 years of age.

At this stage there is often spacing between the teeth especially distal

to the lower canines and mesial to the upper canines (primate spaces),

with the distal surfaces of the second deciduous molars in line with

each other (flush terminal plane).

At 6 years of age the first molars start to erupt, and the permanent

incisors develop lingual to the roots of the deciduous incisors. At this

time also, the ugly duckling stage is evident.

As the child continues to grow, he/she passes through the transition

period from early mixed dentition to late mixed dentition, to the

permanent dentition. Within these periods, there lies a discrepancy

between the mesiodistal widths of the deciduous molars and the

premolars which creates spacing and is termed the leeway space.

This develops to allow the lower permanent molars to move forward


6/79

6

further than the upper molars and establish a Class I molar

relationship (Class I; the mesiobuccal cusp of the maxillary first

permanent molar occludes with the midbuccal groove of the lower

first permanent molar).

2. Malocclusion

Malocclusion is defined as an irregularity of the teeth, OR

Malrelationship of the Dental Arches The majority of

malocclusions are primarily hereditary in nature. (The various types

of malocclusion will be discussed briefly here, the detailed description

of each will be elaborated in the next section)

The etiology of malocclusion is generally categorized into two causes:

(1) Hereditary, such as jaw-teeth size discrepancy, and

(2) Developmental, such as premature loss of teeth or habits (ex.

thumb sucking or tongue thrusting).

Malocclusion may be associated with one or more of the

following:

A. Malposition of the Teeth

This could be caused by:

Tipped teeth which mean that the crown of a tooth is tipped orincorrectly positioned in comparison to the apex.

Displaced teeth in this situation both the crown and the apex aredisplaced.

Rotated teeth the tooth is rotated along its long axis. Teeth in infra-occlusion the tooth has not reached the occlusal

level.


7/79

7

Teeth in supra-occlusion the tooth has erupted pass the occlusallevel.

Transposed teeth two teeth have reversed their positions, forexample a canine taking the place of first premolar.

B. Malrelationship of the Dental Arches

This could occur in any of the three planes of space: antero-

posterior vertical or transverse. The antero-posterior

malrelationship is represented by the Angle Classification,

which deals with the disproportion of the teeth in an antero-

posterior plane. The vertical malrelationship is evident during

the observation of overbite, while the transverse

malrelationship is presented in cases with crossbites.

The most popular and world recognized classification of

malocclusion is the one described by Angle, which deals with

the arch malrelationship in the antero-posterior position.

Angles Classification

This was the first useful orthodontic classification system that

was developed in 1890, and it still used in our present date.

Angles classification system was based on the upper first

molars as being the Key to Occlusion and that the upper and

lower molars should be related so that the mesiobuccal cusp of

the upper molar occludes in the buccal grove of the lower

molar. If this molar relationship existed and the teeth were

arranged on a smoothly curving line of occlusion, then normal

occlusion would result.


8/79

8

Angle then described the three classes of malocclusion, based

on the occlusal relationships of the first molars, which are as

follows:

Class I - The lower first permanent molar is within one-half

cusp width of its correct relationship to the upper first

permanent molar (i.e. the mesiobuccal cusp of the maxillary

first permanent molar occludes with the mid-buccal groove of

the lower first permanent molar.

This is sometimes termed neutro-occlusion. So basically

there is a normal relationship of the molars, but the line of

occlusion is incorrect due to crowded, rotated, spaced teeth, or

others.


9/79

9

Class II - The lower arch is at least one-half cusp width

posterior to the correct relationship with the upper arch. This is

also known as disto-occlusion. This type of malocclusion is

further categorized into two divisions according to the

relationship of the upper central incisors:

Class II Div. 1 - The upper central incisors are proclined or of

average inclination with an increase in overjet.

Class II Div. 2 - The upper central incisors are retroclined. The

overjet is usually average but can be decreased or a little

increased. Sometimes the upper laterals are proclined.


10/79

10

Class III - The lower arch is at least one-half cusp width too far

forward in relation to the upper arch. This is also known as

mesio-occlusion.

In certain situations where early extraction of the first molars

has occurred, the alternative to using the Angles classification

of malocclusion is to use the position of the canine to determine

which type of occlusion the patient has. Usually, in Class I

relationships, the position of the upper canine is between the

embrasure of the lower cuspid and first bicuspid.


11/79

11

In Class II cases, we have a mesial movement of the upper

canine and a distal movement of the lower canine. In Class III

cases, the opposite is true. The upper canine is located more

distal, with the lower canine migrating more mesial.

Other systems have been developed to further aid in classifying

a malocclusion. They are also used when the first molars are

absent. In these cases, an Incisor classification has been

developed. Its benefit is also recognized during orthodontic

treatment. Since one of the main objectives is to correct the

incisor malrelationship during treatment, an understanding of

incisor position is very important.

Incisor Classification:

This does not usually follow the buccal segment relationship.

It can be divided into:

Class I - The lower incisor edges occlude with or lie

immediately below the cingulum plateau (middle part of

the palatal surface of the upper central incisors).


12/79

12

Class II- The lower incisor edges lie posterior to

cingulum plateau of the upper incisors.

There are two divisions

Class II Div. 1 - The upper central incisors are proclined

or of average inclination and there is an increased

overjet.

Class II Div. 2 - The upper central incisors are

retroclined, sometimes the upper laterals are proclined.

Class III - The lower incisor edges lie anterior to the

cingulum plateau of the upper incisors. The overjet may

be either reduced or reversed.


13/79

13

Class I Malocclusion

This is the most common of all the malocclusions.

Dental Features

Labial Segments

The lower incisor edges should occlude with or lie directly

below the cingulum plateau of the upper incisors. Meaning that

there should be a normal antero-posterior relationship between

them.

Buccal Segments

The upper and lower molars are in neutro-occlusion. Because

of the order of eruption, if there is a crowded dental arch, the

last tooth within the arch to erupt will often be impacted orcrowded out of the line of the dental arch. In some cases there

may be an associated crossbite of one or two teeth, anterior

teeth crowding, spacing, deep overbite or openbite, irrelevant of

the canine and molar Class I relationship.


14/79

14

Skeletal Relationships

Antero-posterior

The skeletal pattern is usually a Class I, but it is possible to find

a Class I malocclusion in association with a Class II or Class III

skeletal pattern.

Vertical and Transverse

They are usually within normal range.

Soft Tissue

The soft tissue form and activity are usually within normal

range.

Growth

There is a harmonious growth between the upper and lower

jaw, which accounts for the skeletal and facial balance.

class IMolar and jaw relationship

Growth pattern


15/79

15

Class I Problems and Their Treatment

1. Crowding This may appear in the labial or buccal segments

due to a small or narrow arch, or in the premolar region due to

early loss and drifting of teeth. It can be classified into mild,

moderate, or severe.

There are two ways to measure the crowding:

According to the broken contact: Mild = 1-2 broken contact

Moderate = 3-5 broken contact

Severe = more than 5 broken contacts

According to measurement by mms: Mild = 1-3 mm lack of space

Moderate = 4-8 mm lack of space

Severe = 8 mm

The treatment of crowding depends on the severity of the case.

It can be treated by the following:

1. Stripping to minimize the width of the teeth

mesiodistally. Used in mild, moderate cases of

crowding.

2. Distallization applying forces to teeth to move

them distally and create space. For example the

use of headgears. This is also used with mild

crowding.

3. Expansion widen the arch (upper), also used in

mild to moderate crowding cases.


16/79

16

4. Extraction usually the first premolars are

removed when the crowding is moderate to severe.

2. Spacing This could be localized or generalized.Localized: such as Diastemas. Which could be caused

by low frenal attachments, jaw-size discrepancy, or the

presence of a mesiodens.

TX:-

When the anterior teeth have narrow mesiodistalwidth, and the diastema is less than 5 mm, we can

build up the teeth with a tooth colored material such

as composite, to overcome the space.

When the frenum attachment is low, the treatment ofchoice is a frenectomy in conjunction with appliance

therapy.

Generalized Which is due to a jaw-size to teeth-size

discrepancy. In this case fixed orthodontic appliance is

the method of treatment.

3.Deep Bite Defined as the excessive vertical overlap of the

incisors. Normally the lower incisal edges contact the

lingual surface of the upper incisors at or above the

cingulum.

It may cause traumatic occlusion and impingement of the

palatal tissue. The treatment of this type of problem is


17/79

17

usually by combination of removable and fixed

orthodontic appliances, and in some cases orthognathic

surgery.

4.Open Bite there is no vertical overlap of the incisors, and

there is an evident vertical separation

.

This could be due to:

Dental Problems associated mainly with oral habits

such as thumb sucking or mouth breathing.

Skeletal Problems Arch deficiencies


18/79

18

Treatment of these problems are by eliminating the habit if they

are young in age, or by surgical procedures in adulthood.

5.Cross bite It could be lingual or buccal, anterior or

posterior, unilateral or bilateral, involving one tooth or a

group of teeth. If it present anterior, this could be due to

a pseudo-Class III or a true Class III. If it is posterior, it

is usually due to a narrow upper arch.

Normal Occlusion Unilateral buccal Cross Bite

Bilateral buccal Cross Bite Cusp relation tendency for crossbite

[edge to edge] relationship


19/79

19

Scissors Bite [lingual Cross Bite]

(The upper buccal teeth are occluding buccaly to the lower teeth)

Its causes vary from thumb sucking habits to dental

problems such as teeth inclinations, to skeletal problems.

Treatment usually consists of appliance therapy, and may

be surgery in the future.

6.Localized Teeth Problems Such as impacted or

unerupted teeth. Most commonly observed in impacted

cuspid cases.


20/79

20

Class II Malocclusion

A. Class II Div. 1 Malocclusion

Dental Features

Labial Segments

The lower incisor edges lie posterior to the cingulum plateau of

the upper incisors. There is an increased overjet which may be

due to proclined upper incisors, retroclined lower incisors, or a

skeletal problem. Usually the overbite is increased and

complete.

Note: Overjet is defined as the horizontal overlap of the

incisors. Normally the upper incisors are 2-3 mm ahead of the

lower incisors.

Buccal Segments

The upper and lower first molars are in disto-occlusion,

meaning that the mesiobuccal cusp of the upper first molar is

anterior to the mid-buccal groove of the lower first molar.


21/79

21


Antero-posterior

There is usually a Class II skeletal pattern. In severe

malocclusion cases, with poor skeletal relationships,

orthodontic treatment alone is compromised. In other cases, the

inclination of the lower teeth will compensate for the skeletal

pattern and thus the overjet will be less than expected.

Vertical

The anterior skeletal face height is usually average, although it

may be high. A high angle or dolichofacial pattern is usually

associated with an unfavorable facial profile with little chin

prominence, hence complication orthodontic treatment.

Soft Tissue

The lips are frequently incompetent, which leads to the

uncontrolled proclination of the upper incisors. Sometimes a

lip seal will be maintained but frequently there is a tongue-to-

lower-lip seal with the lower lip lying behind the upper incisors.

Growth

Patients with a Class II div. 1 pattern exhibit more vertical

growth, unlike patients with a Class II div. 2 pattern whom

exhibit more mandibular horizontal growth. A typical Class II

div. 1 case presents with a dolichofacial pattern or Long

Face Syndrome, and has less favorable growth direction of the


22/79

22

mandible than the brachyfacial patient or Square Jaw

Patient in class II div. 2 cases.

classII

Molar and jaw relationship

Treatment:

There are certain indications to treat a Class II div. 1

malocclusion, some of them are:

To correct the anteroposterior relationship and gain a Class I.

To correct the overjet and/or overbite.

For proper esthetic appearance.

Treatment can be divided generally into non-extraction of teeth

to correct the problem, or extraction. Non-extraction treatment

is usually indicated for those cases with:


23/79

23

Favorable growth Mild overjet Acceptable esthetics Teeth are in good position

Extraction is usually indicated in those cases:

Increased overjet and/or overbite Severe crowding Convex profiles Increased skeletal discrepancyUsually the first premolars are the teeth of choice for extraction.

Fixed appliance is the choice of treatment.

If there is skeletal discrepancy, patients should be treated with

the consideration of the growth spurt, so we can take advantage

of growth and allow it to help the treatment.


24/79

24

B. Class II Div. 2 Malocclusions

Dental Features

Labial Segments

The upper central incisors should be retroclined. The upper

laterals may be proclined or retroclined when the upper laterals

are proclined, they are usually mesially inclined and

mesiolabially rotated. The lower anterior segment is frequently

retroclined, which may lead to crowding of the lower incisor

area. This increases the interincisal angle and hence has an

effect on the amount of overbite. The overjet is usually not a

problem here. There is an increase in the lower curve of Spee

and the patient may appear with a gummy smile due to

retroclination of the incisors.

Buccal SegmentsHere the lower arch is at least one-half cusp width post normal

to the upper arch, and there may be crowding due to early loss

of the deciduous molars with a forward drift of the lower first

molars.


25/79

25


Anteroposterior

The profile is usually well balanced, with the chin in a good

position with the rest of the face. In some cases, the skeletal

discrepancy is sever. This may due to an increase in the length

of the anterior cranial base, leading to a more distal positioning

of the glenoid fossa and hence the mandible.

Vertical

The lower facial height is reduced or average. The Frankfort

mandibular plane angle is often low. The lower anterior facial

height may contribute to the depth of the overbite.

Transverse

In rare cases we may find a scissors bite, with the upper

buccal teeth occluding outside the lowers.

Mandibular Positions and Paths of Closure

Usually, the path of closure is a simple hinge movement and the

habitual position of the mandible is the rest position. But in

severe cases, the mandible is habitually postured downwards

and forward. With true posterior displacements of the

mandible, and where there has been a loss of posterior teeth,

patients will complain of pain in the early adult life, leading to

TMJ problems.


26/79

26

Soft Tissue

The lip line here is usually high, with the lower lip covering more than the

occlusal half of the upper incisors. There may be an accentuated

labiomental fold, and an increased nasiolabial angle with flattening of the

upper lip profile.

Growth

These patients exhibit a closing growth rotation, which contributes in part to

the reduced facial height and the deep overbite. Treatment in these cases is

difficult.

Oral Health

In cases with severe overbite, direct trauma (traumatic bite) to the gingival

mucosa may occur. This is due to the lower incisors occluding with the

palatal mucosa and the upper incisors occluding with the labial mucosa. In

these cases proper oral hygiene is a must and treatment of the traumatic

occlusion is indicated.

Treatment

This type of malocclusion is the most difficult to treat. Treatment modalities

differ and can include any of the following:

1. No treatment: when the facial appearance is acceptable.

2. Upper removable appliance therapy. To reduce the overbite.

3. Fixed appliance therapy. For both upper and lower jaws.

4. Orthognathic surgery: It is indicated in the most severe forms of Class II

div. 2, where the overbite is very deep and traumatic to the gingiva, and the

facial profile is very poor.


27/79

27

Class III Malocclusion

Dental Features

Labial Segments

There is a Class III incisor relationship when the lower incisor

edges are lying anterior to the cingulum plateau of the upper

incisors. The lower incisors may lie anterior to the uppers so

that there is a reverse overjet. The upper incisors are often

crowded and they are usually proclined. The lower incisors are

usually spaced and frequently retroclined. This inclination

compensates the extent of the underlying sagital arch

malrelationship.

Buccal SegmentsThe lower arch is at least one-half cusp width too far forward

relative to the upper arch.

Usually the upper arch is crowded with canines buccally

excluded, while the lower arch is well aligned. It is not

uncommon to observe a crossbite in the buccal segments

because of a narrow maxilla, which may be unilateral or

bilateral. A unilateral crossbite is usually associated with

lateral displacement of the mandible to obtain maximal

intercuspation.


28/79

28


Anteroposterior

There is a combination of factors which leads to this

malrelationship. The mandible is usually large, with a short

retrognathic maxilla. The patient will appear with a concave

profile. There is a more forward position of the glenoid fossa

on the skull base so that the mandible is more anteriorly

positioned than usual, with a short anterior cranial base.

In some cases, the dental pattern is a Class III while the skeletal

pattern is a Class I.

Vertical

The Frankfurt mandibular plane angle is usually high, with an

associated reduced overbite or anterior open bite. The

intermaxillary height is an important factor to consider.


29/79

29

Transverse

In most cases the maxillary base is narrow with a wide

mandibular base. This transverse discrepancy is compensated

for by a buccal inclination of the upper teeth and a lingual

inclination of the lower teeth. It is common to see crossbites in

the buccal segments due to a large mandible and a narrow

maxilla.

Mandibular Positions and Paths of Closure

In patients with a mild Class III malocclusion in incisors meet

edge to edge in centric relation, but in order for the mandible to

obtain a position of maximal occlusion, there is a forward

displacement of the mandible which accentuates the skeletal

discrepancy. When there is a unilateral crossbite with the teeth

in occlusion there will usually be an associated lateral

displacement of the mandible on closure.

In cases of skeletal disharmony, there will be a more

pronounced anterior displacement of the mandible, and it will

be more difficult if not impossible for the mandible to retrude to

obtain maximal occlusion. In fact, the only way the lower arch

can meet with the upper arch in maximum occlusion is through

the forward displacement of the mandible.

Soft Tissue

In cases where the lips are frequently incompetent, the anterior

intermaxillary height is large. These cases usually present with


30/79

30

an anterior open bite with an adaptive swallowing behavior,

where the tongue comes forward into the gap between the

incisors.

Growth

Here any growth is unfavorable, since the mandible may grow

more prognathic. When the height of the intermaxillary space

is normal or reduced, growth may worsen the reverse overjet

and the horizontal profile of the face. When the height of the

intermaxillary space is increased with growth, the tendency to a

skeletal anterior open bite may become greater.

Class III

Molar and jaw relationship

Oral Health


31/79

31

Mandibular displacements due to occlusal disharmonies

eventually may be associated with muscle pain. Also when

there is a premature contact in the incisor region there may be

gingival recession around one or more lower incisors. And in

cases with an anterior open bite, periodontal changes can be

expected around the non-functional teeth.

Treatment

Can be and is not limited to:

1. Removable appliance therapy, used for example insimple tipping movements of the upper incisors.

2. Functional Appliance. Can be used in mild cases.3. Protraction headgears chin cup therapy, and maxillary

expansion. This mode of treatment is usually used in

young patients, with a narrow maxilla, and a straight or

concave profile.

4. Fixed Appliances. For both upper and lower arches.Treatment here can be done with extraction or non-

extraction of teeth. If teeth are to be extracted, a

common approach is to extract the upper second

premolars and tip the anterior teeth forward, and to

extract the lower first premolars to tip back the lower

anterior teeth, thus camouflaging the Class III pattern.

5. Orthognathic Surgery. Usually a combination ofmandibular setback and maxillary advancement.


32/79

32

II. Radiographs

Radiographs are very important diagnostic aids in all aspects of thefield, and especially in orthodontics.

There are two main types of radiographs:

Intraoral Radiographs which includes periapicals, bitewings

and occlusal films.

Extraoral Radiographs includes orthopantomographs (OPG),

hand-wrist radiographs, posteroanterior radiographs and lateral

cephalometrics.

The following sections will cover extraoral radiographs in detail.

1. Orthopantomographs

Also termed panoramic radiography or rotational radiography. It is a

radiographic procedure that produces a single image of the facial

structures, including both the maxillary and mandibular arches and

their supporting structures, such as the nasal cavity, maxillary sinuses

and the temporomandibular joints.

The principles of the panoramic radiography where first described by

Numata in 1933 and Paatero in 1948.

Originally the patient and the films rotated and the x-ray beam

remained stationary. But this method was superceded by the

development of apparatus which have the tube and the film rotating

around the patient.


33/79

33

The x-ray source and film are simultaneously moved parallel to each

other in opposite directions. While taking the radiograph, the

Frankfort Horizontal Plane (FHP), should be parallel to the floor, and

the occlusal plane should be lower anteriorly by 20-30 degrees, with

the patient biting on a bite block.

Caution should be taken on the position of the chin:

If the chin is tipped too high to the horizontal plane, the

mandible will be distorted.

If the chin is tipped too low the hard palate will superimpose

the roots of the maxillary teeth.

To make sure of the distortion, we can check the width of the

permanent mandibular teeth (molars) bilaterally. If one of them

is wider than the other one by 20% the radiograph should be

retaken.

Advantages of OPGs

The film is extraoral, making it more comfortable for the

patient.

A broad anatomic region is imaged, which includes the maxilla

and the mandible.

It exposes the patient to less radiation.

It is quick, convenient and easy for the assistant to take.

It can be performed on patients who cannot open their mouths

and cannot tolerate intraoral radiographs, especially edentulous

patients or patients with a suspected pathosis.


34/79

34

The time required for the procedure is short 3-4 min. including

patient positioning and actual exposure.

Accepted by patients during presentations and education.

Gross lesions are visible.

Disadvantages

Does not give the fine anatomic details such as the alveolar

crest, margins of pathological lesions, bone pattern, caries, etc.

The image may be distorted if the patient is situated outside the

focus.

Magnification, geometric distortion, overlapped images of

teeth, especially premolar region.

The projection can be taken only at one angle.

The view of the temporomandibular joint is distorted.

Expensive machine (3-4x more than the intraoral machine).

Indications for Usage

To assess the patients dental age based on the development and

progress of mineralization of the teeth, eruption time and

exfoliation of the primary teeth. So a comparison of the

chronological and skeletal age can be done.

It used to evaluate:

Teeth: Teeth present, missing congenitally or impacted,

ectopic eruption, malpositioned teeth, the presence or

absence of third molars, supernumeraries, quality of


35/79

35

restorations, resorption pattern of deciduous teeth,

calcification of permanent teeth, asymmetric resorption

of deciduous molars, integrity of root structures.

Bone: Alveolar bone, level of interdental crest, bone

resorption (horizontal, vertical), infrabony pockets,

trabecular pattern wide marrow space (esp. in young

growing children), or narrow trabecular spaces (in older

children and adults).

Pathology: Pathological lesions, cysts, tumors, extensive

or unique pathosis, ankylosis of deciduous teeth,

susceptibility to caries, active carious lesions, root

resorption.

2. Occlusal Films

It is required to visualize relatively large segment of dental

arch, including the palate, floor of the mouth, and a reasonable

extent of lateral structures.

It is indicated to:

Locate roots, supernumerary, unerupted and impacted teeth

especially cavities and third molars.

Localize foreign bodies and stones in the salivary glands duct.

Evaluate the integrity of the maxillary sinus outline.

Provide information relative to the fractures of the mandible

and maxilla.


36/79

36

To determine to medial and lateral extent of pathosis (e.g.

cysts).

3. Hand and Wrist Radiographs

Hand and wrist radiographs are one of the most important diagnostic

aids when planning orthodontic treatment. Predicting the pattern of

growth; that is the amount, direction, duration, location and timing of

the onset of pubertal growth is important for the orthodontist when

planning therapy and coordinating orthodontic treatment with the vital

growth process. Estimation of the skeletal age of bones or bone age

aids in determining the physical maturation status of the child. One of

the indicators to verify the pubertal growth spurt is annual

measurement of the body height, but this will only give a retrospective

picture of what has happened. Whereas our interest is to know what

will happen in the future to judge the development stage of the child

in relation to the childs own growth curve, in order to decide whether

the pubertal growth spurt has started or passed.

Advantages of the Hand and Wrist Radiographs

It differentiates the certain developmental stages towards full

physical development.

The sequence of such developmental or morphological changes

is equal in all humans.

It is technically simple to make roentgenograms of the hand.

An individual will pass through a regular series of changes in


37/79

37

size and shape of the ossification centers of bone during their

progress towards maturity. Several systems have been

developed to evaluate these series of growth changes. One

which will be described in detail here, is a system produced by

Leonard Fishman. Fishmans analysis is based on skeletal

maturation assessment (SMA). This system uses four stages of

bone maturation located at six anatomic sites: the thumb, third

finger, fifth finger and radius. In these six sites eleven

maturational indicators (SMIs) are found to cover the entire

adolescent development period.

Sites of Skeletal Maturity Indicators

Which are related to: widening of the epiphyseal discs in one of

the phalanges on the third or fifth finger, visibility of the

ulnarmetacarpophalangeal sesamoid on the first finger (thumb),

capping of selected epiphyses over their diaphyes, and the

fusion of selected epiphyses and diaphyses. In addition to that

ossification of the hook of the hamate and pisiform bone is also

taken into consideration.


38/79

38


39/79

39


40/79

40


41/79

41


42/79

42

The development or maturation stage for the individual patient can be

plotted on the growth curve:

The best treatment time for orthodontic patients is 1-2 years before the

growth spurt, after that time usually no growth will occur. Hence, the

advantage of growth will be missed and treatment might be

compromised.


43/79

43


44/79

44

For ease of interpretation, the first step is to determine the

presence or absence of the adductor sesamoid of the thumb


45/79

45

4. Cephalometrics

Cephalometrics was first introduced to the world by Hofrath in

Germany and Broadbent in the United States. Cephalometric

radiography means measuring the head in the living individual

through the use of radiographs. The original purpose of

cephalometrics was to conduct research on growth patients in the

craniofacial complex, but was soon used afterwards as a method to

evaluate dentofacial proportions and clarify the anatomic basis for a

malocclusion. Nowadays, lateral cephalometric radiographs are

routinely used in orthodontic practices.

A cephalograph, which is a standardized radiograph of the head

(cranium and face), is taken for the patient by the use of a machine

termed the Cephalostat (cephalus meaning the skull or head, and

stat meaning fixed or static position).

The basic equipment required to obtain a cephalometric view consists

of an x-ray source, an adjustable cephalostat, a film cassette with

radiographic intensifying screens, and a film cassette holder.

Components of the Cephalostat

The cephalostat consists of the following:


46/79

46

Ear Rods: Two in number, one right and one left. These are

tightened into the external auditory meatuses so that the patient

is maintained in the mid-sagittal plane. Each ear rod has a

metal ring of the same dimension, and in a correctly aligned

cephalostat the radiograph shows a single ring. If two rings are

seen it indicates an improperly aligned cephalostat.

Nasal Pointer: Which rest on the bridge of the nose (usually at

the soft tissue nasion).

Orbital Pointer: This optional, and if present it is fixed at the

orbital region.

A Metal Millimeter Scale: This is fixed vertically to the nasal

pointer to indicate the amount of magnification or distortion.

The patient is placed within the cephalostat using the adjustable

bilateral ear rods placed within each auditory meatus, usually while

the patient is in a standing position. The mid-sagittal plane of the

patient is vertical and perpendicular to the x-ray beam. It is also

parallel to the film plane, which in turn is also perpendicular to the x-

ray beam. The patient Frankfort plane (line-connecting the superior

border to the external auditory meatus and the infraorbital rim) is

oriented parallel to the floor. The distance between the x-ray source

and the mid-saggital plane of the patients head is kept at a minimum

of 5 feet (150 cm), so reduce magnification.


47/79

47

A fast Kodak blue brand 8 x10 film is used. The film is

exposed for 4/10 of 7/10 sec. at 90 KVP and 10MA, to

penetrate the hard tissue and provide good details of both the

hard and soft tissue.

Two views can be used with this type of radiographic method

1. Posteroanterior View:

It shows the vertical and transverse dimensions of the head The

primary indication for obtaining a posteroanterior cephalometric

film is the presence of facial asymmetry. A tracing is made and

vertical planes are used to illustrate transverse asymmetrics.

Lines are drawn through the angles of the mandible and the outer

borders of the maxillary tubersity. Vertical asymmetry can be

observed by drawing transverse occlusal planes (molar to molar)

at various vertical levels and observing their vertical orientation.


48/79

48

2. Lateral Head or Profile View(lateral cephalometrics):

It shows the vertical and anteroposterior or saggital dimensions.

This type is most commonly used during orthodontic diagnosis.

Uses of Cephalometrics

An Aid to Diagnosis1. Classify the type of face.2. Show the relationship between the basal parts of the

maxilla and the mandible.

3. Evaluate the soft tissue profile.4. Evaluate the position of the incisors in relation to the

basal parts and the soft tissue profile.


49/79

49

A pre-treatment record prior to the placement ofappliance, particularly where movement of the upper

and lower incisor is planned.

Monitoring the Progress of Treatment1. Anchorage requirements and incisor inclinations.2. Movement of unerupted teeth.3. Movement of treated teeth and their inclination.

To make a growth prediction when the orthodontictreatment is to be conducted during the growth period.

Research PurposesInformation about growth and development by

longitudinal studies (serial cephalometric radiographs

from birth to the late teens).

Detecting for any abnormalities or pathology e.g. apituitary tumor of patency of the airway as enlarged

adenoids.

Tracing Technique

Certain materials are used for this purpose, which are:

Tracing paper 3 H drawing pencil Gum eraser Transparent millimeter ruler


50/79

50

Transparent triangle Scotch tape Template View box

Method of Tracing

1. Place the cephalograph on the table with the profilefacing to your right hand.

2. Place the tracing paper over the film (the dull surfacefacing you), with the lower border of the paperextending about one inch below the chin point.

3. Tape the upper corners of the tracing paper to theradiograph.

4. The tracing should be carried out in a dark room on alight-viewing box.

5. Trace the soft tissue profile, then the hard tissueprofile, and then the dentition according to the

following tracing procedure.

6. If bilateral structures are present, draw both of themand take the average of the two.

7. Trace the reference points.

Tracing Procedures

1. Trace the soft tissue profile starting with the forehead, thennose, then lips, then chin till the throat angle beyond the

chin.


51/79

51

2. Trace hard tissue profile, start with the forehead and thefrontal sinus.

3. Trace the nasal bone.4. Trace the anterior nasal spine and the anterior contour of the

maxilla up to the interdental alveolar crest between the

central incisors.

5. Trace the floor of the nose and the roof of the palate. Tracethe posterior nasal spine.

6. Trace the anterior contour of the mandible starting from theinterdental crest between the lower incisors.

7. Trace the outline of the chin up to the symphysis.8. Trace the lower border of the mandible from the symphysis

to the angle of mandible.

9. Trace the posterior border of the ramus.10.Trace the orbit from the supra orbitale ridge to the most

inferior portion on the lower border of the orbit known as

orbitale.

11.Trace the zygomatic bone from the lateral contour of theorbit down to the triangular image. The lowest projection of

the triangular image is called key ridge.

12.Trace the pterygomaxillary fissure which is seen as aninverted tear drop shape just above the posterior nasal spine.

The anterior contour of the fissure represents the posterior

surface of the maxilla and its posterior contour represents

the pterygoid bone.

13.Trace the shadow of the external acustic meatus. It appearsas an oval radiolucency or opaque ring shadow due to ear


52/79

52

rods and it lies behind the upper most surface of the

condylar head.

14.Trace the sella turcica (saddle shaped pituitary fossa).15.Trace the most prominent upper central incisor from crown

to root.

16.Trace the most prominent lower central incisor..17.Trace the occipital bone.

Note: Use the template to trace the central incisors

Anatomic Points (Landmarks) of the CephalometricA. Cranial Base

1. Nasion (N) The most anterior point on the fronto nasalsuture.

2. Sella (S) The mid-point of sella turcica.

B. Mid-Face

1. Orbitale (or) The most inferior point on the lower marginof the orbit.

2. Porion (po) The most superior point on the bone externalauditory (acustic) meatus.

In case of metal ring, it located 4.5 mm above the center of the

metal ring.

C.Maxilla

1. Anterior Nasal Spine (ANS) The tip of anterior process ofthe maxilla or the most anterior point on the maxilla at the

level floor of the nose.


53/79

53

2. Posterior Nasal Spine (PNS) The most posterior point onthe maxilla at the level floor of the nose.

3. Point A (A) The deepest point on the anterior contour ofthe maxilla between ANS and alveolar crest usually it is

approximately 2 mm anterior to the apices of maxillary

central incisor.

D. Mandible

1. Point B (B) The deepest point on the anterior contour ofthe mandible between the chin and alveolar crest.

2. Pogonion (pog) The most anterior point on the curvatureof bony chin.

3. Menton (Me) The most inferior point on the mandibularsymphysis.

4. Gonion (Go) The most inferior posterior point on theangle of the mandible.

E. Soft Tissue

1. Upper Lip Point (UL) The most anterior point of upper lipprofile.

2. Lower Lip Point (LL) The most anterior point of lower lipprofile.

3. Soft Tissue Pogonion (pog) - The most anterior point on theprofile of soft tissue chin.


54/79

54

Cephalometric Horizontal Planes and Lines

SN Line This line, connecting the mid-point of sella turcica

with nasion, is taken to represent the cranial base.

Frankfort Plane This I the line joining porion and orbitale.

Maxillary Plane The line joining anterior nasal spine with

posterior nasal spine.

Mandibular Plane the line joining gonion and menton.

Cephalometric Analysis:Angular and Linear Measurements

A series of angles in degree and a few linear distances in

millimeter are measured and compared normal values. The

differences from the normal are noted as plus or minus. When

the differences are below or above the normal ranges, they are

considered as abnormal.

The angles used in cephalometric analysis are formed at the

junction of two planes, could be horizontal or vertical planes.

The whole cephalometric analysis can be divided into three parts.

1. Skeletal relationship2. Dental relationship3. Soft tissue relationship

Skeletal Analysis

A.Antero-Posterior Relationship


55/79

SNA: Measured at the junction of SN line and NA line.It evaluates the

antero-posterior position of the maxilla in relation to the anterior cranical

base.The normal average is 813 (normal or orthognathic maxilla). When this

angle is above the normal range it would be interpreted as protruded or prognathic

maxilla, and when it is below the normal range, retruded or retrognathic maxilla.

SNB: Measured at the junction of SN line and NB line. It evaluates

the antero-posterior position of the mandible in relation to the anterior

cranial base.The normal average is 783 (normal or orthognathic

mandible). When this angle is above the normal range, it would be

interpreted as protruded or prognathic mandible, and when it is below

the normal range, retruded or tetrognathic mandible.

ANB: This angle is the difference between SNA and SNB angle and

indicates the amount of skeletal discrepancy between maxilla and

mandible in antero-posterior position.The normal average is 3

3(skeletal Class I).A larger than normal angle would indicate of

skeletal Class II and smaller than 1 angle skeletal Class III.


56/79

56

B. Vertical Relationship:

SN-Mxpl: Measured at the intersection of SN line to maxillary plane

and expresses the vertical inclination of the maxilla in relation to the

anterior cranial base. The mean value is 83 (normal inclined

maxilla) value greater than normal indicate a posterior inclination of

the maxilla, smaller values indicate an anterior inclination of maxilla.

FH-Mnpl: Measured at the intersection of Frankfort plance and

mandibular plane and expresses the inclination of the mandible. The

mean value is 284 (normal inclined mandible).

Angles greater than normal indicate the mandible is growing

downward and backward or the mandible is steep (posterior

inclination of the mandible). Angles less than normal indicate

anterior inclination of mandible, mandible is growing forward and

upward (mandible is horizontal)


57/79

57

MMpA: Measured at the intersection of maxillary plane with

mandibular plane and relates the inclination of the mandible and the

maxilla to each other. The mean value is 274 (normal interbasal

angle). If the angle exceeds the normal there is skeletal open bite,

whereas an angle less than the mean indicates skeletal deep bite.

Facial Proportion (FP): This is the ratio of the lower facial height to

the total anterior facial height and it is calculated as a percentage

according to this equation

lower facial height

FP = ---------------------- x 100

Total facial height

Total facial height = lower facial height +upper facial height.

Lower facial height: This is a linear measurement from menton

perpendicular to maxillary plane.

Upper facial height: This is a linear distance is measured from Nasion

perpendicular to maxillary plane.

In normal faces this index has a value of about 50% 2% (normal

lower height). A larger than this ratio will indicate increased lowerfacial height, smaller than this value will indicate decreased lower

facial height.


58/79

58

Note:The MMpA reflects both posterior lower facial height and

anterior lower facial height. Therefore in the case of patient who has

an increased MnpA but average facial proportion it would appear that

the posterior facialheight is reduced (opposed to an increased lower

facial height which result in creased MMpA). This would be noticed

when there is a discrepancy between the measurements of the facial

proportion and the maxillary mandibular plane angles (MMpA).

Dental Relationship:

Uinc-Mxpl: Measured at the intersection of the long axis of the upper

central incisor with the maxillary plane.

It evaluates the antero-posterior inclination of the most prominent

maxillary central incisor.

This angle averages 1096 (normal inclination of upper incisor).

A larger than normal angle would indicate proclination of the upper

central incisor and smaller than normal angle would indicate

retroclination of maxillary incisors.


59/79

59

Uinc-NA: This is a linear distance measured in millimeter from the

most prominent incisal edge of the upper incisor perpendicular to NA

line.It averages 42 mm (normal position of upper incisor)

A larger than normal angle would indicate protrusion of upper central

incisor and a smaller than normal angle would indicate retrusion of

the central incisor.

Linc to MnPL: Measured at the intersection of the long axis of the

lower central incisor with mandibular plane. It evaluates the antero-

posterior inclination of the most prominent mandibular central

incisor.A larger than normal angle would indicate proclination of

lower incisor and a smaller than normal angle would indicate

retroclination of the mandibular incisor.


60/79

60

Linc-NB: This is a linear distance measured in millimeter from the

most prominent incisal edge of the lower incisor perpendicular to NB

line. It averages 42 mm (normal position of lower incisor).

A larger than normal angle would indicate protrusion of lower central


the mandibular incisor.

Linc to A-Pog: This is a linear distance measured in millimeter from

the incisal edge of the lower incisor perpendicular to A-Pog line.This

measurement averages +12 mm (normal position of lower incisor). A

larger than normal angle would indicate protrusion of lower central


the mandibular incisor.


61/79

61

To have a pleasing facial appearance, the tip of lower incisor lay on or

just in front of this line.

Uinc-Linc: The interincisal angle measured at the junction of the

long axis of upper central incisor with the lower central incisor.

It averages 1355 (normal proclination of upper and lower central

incisors). The angle decreases with proclination of upper and lower

incisors and increase with retroclination of incisors.

Soft Tissue Relationship:

Upper Lip-EL: This is a linear distance measured from the most

anterior point on the upper lip perpendicular to esthetic plane (tip of

the nose to the soft tissue pogonion).It averages 2 to 4 (normal

position of upper lip which is inside the line). A larger angle indicates


62/79

62

the protrusion of the upper lip and a smaller angle indicates the

retrusion of the upper lip.

Lower LipEL: This is a linear measurement from the most

anterior point on the lower lip perpendicular to esthetic plane.

It averages form 0 to 2 inside the esthetic line (normal position of

the lower lip).A larger angle indicates the protrusion of the lower

lip and a smaller angle indicates the retrusion of the lower lip.


63/79

63


64/79

64

IV. Model Analysis

The practical evaluation of the study model is an important step

during the diagnosis and treatment planning of an orthodontic case.

This includes observing the model in three different views: lateral,

frontal and horizontal.

Lateral View: We can observe from this view the following:

Angle classification Incisal classification Overjet (horizontal relationship) Overbite (vertical relationship), lateral overbite or

supraeruption.

Curve of Spee Inclination of the front teeth, primary evaluation (best done

on cephalometrics)


65/79

65

Frontal View: The following can be seen:

The midline, upper or lower. We can determine the palatalmidline by using a symmetroscope

Deviating axial inclination, meaning the mesial, distalbuccal or lingual tipping of the front teeth.

Crossbite, unilateral or bilateral, including one tooth or agroup of teeth.

Scissors bite, also unilateral or bilateral, individual or agroup of teeth.

Diastemas, we should determine the amount in millimeters.

Horizontal View: Determine the following:

Eruption stage, deciduous/mixed permanent. Width of the alveolar process. Shape of the dental arch, ellipsoid/parabolic. Width of the dental arch, the intercanine and intermolar

distance.

Deviation in tooth morphology, ex. Peg. Shapelateral/fusion.

Space condition, Moyers analysis, Nance Anaylsis/BoltonsAnalysis

One of the most important aspects when viewing the study models is

to observe the amount of space required for the eruption of teeth, also

termed the space condition, as mentioned above. In order to estimate


66/79

66

if there is any arch discrepancy and space available, and whether we

need to extract, the following analysis Model Analysis has been

developed:

Plaster Model Analysis:

The most common analysis used are:

1. Mixed dentition analysis, termed Moyers Analysis2. Arch length analysis, termed Nance Analysis3. Tooth size analysis, termed Boltons Analysis

1. Mixed Dentition Analysis, Moyers AnalysisThis analysis is based on measurement of the mandibular permanent

incisors. A quantitative assessment of crowding may be obtained by this

mixed dentition analysis. The space available in each dental arch is

measured on the study models and the sum of the mesio-distal dimension

of the unerupted teeth is determined by measuring the mesio-distal

dimensions of the four erupted mandibular permanent incisors, and

predicting the combined sizes of the unerupted canine and premolars

from the table. The following diagrams show the method used step by

step:


67/79

67

How to apply Moyers Analysis

1. Determine the maximum mesiodistal width of each of the four lowerpermanent incisors in the study model. Calculate their sum.

2. From the incisors value determine:a. The predicting size for unilateral upper 3, 4 and 5 (cuspid, first and

second bicuspid). This can be found from the probability charts on

the following page. The upper half of the chart is for the upper

teeth, and the lower half is for the lower teeth, this value is termed

the space required.

b. The predicting size for unilateral lower 3, 4 and 5 from the lowerprobability chart (this value is termed the space required).


68/79

68

3. Calculate the space available after alignment of upper and lower incisorseach arch separately. This value determines the space available needed

to accommodate 3, 4 and 5.

4. Space available space required = will give the space adequacy orinadequacy for the non-erupted 3, 4 and 5.


69/79

69


70/79

70

2. Arch Length Analysis, Nance Method

The amount of space available is determined by adapting a length of

0.025 inch diameter brass wire to fit from the mesial marginal ridge of

the left first permanent molar around the arch to the mesial marginal

ridge of the right mandibular first permanent molar. The brass wire

should pass over the imagined correct position of the cuspid, the center of

the occlusal surfaces of the bicuspids and the incisal edge of the most

labial of the incisor teeth. The wire should be a smooth arch, free from

kinks and should simulate the desired arch form. Adjustment to the arch

form should be made if a mandibular buccal or lingual crossbite is

present.

The length of the brass wire, determined in millimeter, is regarded as the

available space for the total complement of the dentition. Which consistsof: the 1

stand 2

ndbicuspids, cuspids and lateral and central incisors of

both the right and left sides of the mandibular arch.

It is important to recognize that the available space may or may not be

adequate for the proper alignment of the teeth.

The required space is determined by measuring the mesiodistal width of

each tooth from the right 2nd

bicuspid to the left 2nd

bicuspid, then

calculating the sum.

The space available space required = will give us the space adequacy or

inadequacy to accommodate the teeth.


71/79

71


72/79

72

3. Tooth Size Analysis, Bolton Analysis

The determination of tooth size ratios between the maxillary and

mandibular teeth is essential for proper orthodontic diagnosis, treatment

planning and result prediction. This relation determines:

Teeth interdigitation Excessive overbite Overjet Spacing between teeth

The desirable ratio is necessary to attain an optimum interarch

relationship. If the analysis indicates a marked deviation, it can give an

insight into the required pattern of treatment and extraction. The Bolton

procedure is used in this case to determine the overall ratios. It is as

follows:

a. The sum of the mesiodistal diameter of the 12 maxillary teeth andthe sum of the mesiodistal diameter of the 12 mandibular teeth

including the first molar is calculated, this called the overall ratio:

Sum of 12 mandibular teeth

Overall ratio =---------------------------------- x 100 = 91.3%

Sum of 12 maxillary teeth

b. If the overall ratio is less than 91.3%, then the maxillary toothmaterial is excessive. We can determine from the table the desired

size of the mandibular 12 teeth, appropriate for the actual size of


73/79

73

the maxillary 12 teeth. The value represents the excessive amount

of mandibular tooth material.

c. We can use the same equation for the anterior 6 teeth only fromcanine to canine. This called the Anterior Ratio:

Sum of 6 mandibular teeth

Anterior Ratio = ----------------------------- x 100 = 77.2%

Sum of 6 maxillary teeth

Again if the ratio is less than 77.2%, the maxillary teeth are excessive:

How to apply the Boltons Analysis

1. If the overall ratio of the 12 mandibular and 12 maxillary teeth ismore than 91.3%, then the teeth that are at fault are the 12

mandibular teeth, meaning that they are excess in size. From the

table in the following page, we determine what the corrected sum

of the 12 mandibular teeth should be (this is achieved by locating

our actual sum of the 12 maxillary teeth which we have already the

chart, this is termed the corrected mandibular.

2. If the overall ratio is less than 91.3%, then the teeth that are at faultare the 12 maxillary teeth, meaning that they are excess in size.

The same procedure is done, but here we take the actual sum of the

12 mandibular teeth instead, and locate our corresponding

maxillary value from the chart.

3. When determining the anterior ratio, the same procedure as aboveis used, calculations are done when the amount is more than 77.2%

or less than 77.25.


74/79

74


75/79

75


76/79

76

V. Orthodontic Appliances

There are three basic types of orthodontic appliances:

1. Removable Orthodontic Appliances: These are generally used tocorrect minor malocclusions where only a tipping movement is

necessary. The forces are produced by various types of springs formed

from arch wires. These type of appliances are also used to stabilize or

retain treatment results at the end of treatment of fixed appliances.

2. Functional Appliances: Are also removable appliances, but contrary tothe ordinary orthodontic device which acts in one jaw only, and where

the force arises from a spring, the functional appliances influence both

jaws and the force system is created by the jaw musculature. Duringfunction (mainly swallowing) the muscle forces are transmitted to the

teeth through the appliance and thereby initiate tooth movement.

Functional appliances may even produce some orthopedic changes. A

typical example of a functional appliance is the activator.

3. Fixed Appliances: The term fixed appliances is usually used for a fullbonding/banding appliance system with tubes and brackets attached to

most of the teeth. There are numerous types of brackets and tubes. The

principles, however, are the same. The brackets and tubes that are


77/79

77

rigidly attached to the teeth, enable the different qualities of the

orthodontic wires to be transferred to the teeth, and in addition, they may

have built in qualities which are released when the orthodontic wires are

placed into the tubes and bracket slots.

The fixed appliance systems are designed for active treatment, but some

fixed elements may even be used to stabilize results of active treatment,

such as lingual retainers.

Basic Elements of Orthodontic Fixed Appliances

Various types of brackets are used as attachments on incisors, canines

and premolars, whereas tubes are used on the molars. The brackets

and tubes may be attached directly to the tooth by bonding the bracket

base directly o the tooth surface using the acid etch technique, or they

may be welded to orthodontic bands which are cemented on the tooth.

There are also many additional attachments such as lingual buttons,

eyelets, hooks, etc., that are used to supplement the basic bands,

brackets and tubes.

Replaceable arch wires are used as the basic elements of fixed

appliances. These arch wires engage the tubes and the slots in the

brackets. It is along these arch wires that the teeth move when

orthodontic treatment is undertaken. In order to suit the whole range

of working routines experienced throughout a course of orthodontic

treatment, the characteristics of such arch wires must be specially

adapted to meet such varied demands. One therefore finds that there

is a whole range of wires with varied cross-sectional diameters and

different degrees of hardness and elasticity.


78/79

78

Some Standard Orthodontic Pliers

The following are some pliers used in an orthodontic practice:

1. Bird peak plier: used for forming loops in rectangularwires.

2. Orthodontic cutter: used for cutting wires.

3. Adams plier: used for construction and adjustment ofAdams clasps.


79/79

VI. References:

1. Proffitt, W.R. and Fields, HW. Contemporary Orthodontics. Secondedition, Mosby Yearbook Inc., St. Louis Missouri, 1993.

2. Thilander, B. and Ronning, O. Introduction to Orthodontics. Fifth edition,Printed by Minab/Gotab, Stockholm, 1985.

3. Walther, D.P. and Houston, W.J. Orthodontic Notes. Fifth edition,Butterworth-Heinemann Ltd., Oxford, 1994.

4. Wisth, P. Introduction to the Edgewise Technique, A Technical Manual,University of Bergen, Norway, 1985.

Documents

431 Pds Practical Manual