1. Introduction to Fixed Prosthodontics

8/10/2019 1. Introduction to Fixed Prosthodontics

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DDS

YEAR 4

Fixed Prosthodontics

The scope of fixed prosthodontic treatment can

range from the restoration of a single tooth to the

rehabilitation of the entire occlusion.

Single teeth can be restored to full function, and

improvement in cosmetic effect can be achieved.

Missing teeth can be replaced with fixed

prostheses that will improve patient comfort and

masticatory ability, maintain the health and

integrity of the dental arches, and, in manyinstances, elevate the patients self-image.

A crown, is a cemented restoration that

covers or veneers the outer surface of

the clinical crown.

If it covers all of the clinical crown, the

restoration is a full veneer crown.

If only portions of the clinical crown are

veneered, the restoration is called a

partial veneer crown.

TERMINOLOGY

A full veneer crown covers all of

the clinical crown of the tooth

It may be fabricated entirely of a gold

alloy or some other untarnishable

metal, a porcelain fused to metal

(PFM), or an all-ceramic material.

A partial veneer crown covers

only portions of the clinical crownof the tooth.

E.g., Three-quarter crown, covers

the clinical crown except for the

facial portion.

Intra-coronal cast restorations are those that

fit within the contours of the clinical crown ofa tooth.

Inlaymay be used as single-tooth

restorations for proximo-occlusal lesions

with minimal to moderate extensions.

Onlay may be used as single-tooth

restorations for restoring more extensively

damaged posterior teeth when modified with

an occlusal coverage.

TERMINOLOGY


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Inlays made of gold alloy (A), or

ceramic material (B)

Onlay is an intra-coronal restoration

with an occlusal coverage.

The all-ceramic laminate veneer, is

a cemented restoration consists of

a thin layer of dental porcelain that

is bonded to the facial surface of

the tooth to improve cosmetic

appearance.

TERMINOLOGY

A laminate veneer is bonded to thefacial surface of a tooth with resin

The fixed partial denture is a prosthetic

appliance replaces one or more

missing teeth which is attached by a

cementing medium to natural teeth,

roots, implants. This type of restoration

has long been called a Bridge

TERMINOLOGY

The abutmentis a is any tooth, root or

implant which gives attachment and supportto the fixed partial denture.

The retainers, are extra-coronal restorations

that are cemented to the prepared abutment

teeth.

Apontic, is the artificial tooth replacing the

missing tooth in the fixed prosthesis. Pontics

are attached to the retainers

TERMINOLOGY


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The connectors are the portions of the

bridge uniting the individual parts of the

bridge (pontic and retainer).

They may be rigid (solder joints or cast

connectors) or nonrigid (precision

attachments or stress breakers).

Connector

Retainer RetainerPontic

A cantilever bridge is a fixed partialdenture that attaches to adjacent teeth

on one side of the bridge only.

Simple Cantilever Spring Cantilever

A Fixed-Movable bridge is a prosthesis

where the artificial tooth or teeth is rigidly

supported on one side, usually the distal end

by one or more abutment teeth and includes

a minor retainer on the other side with a

movable joint.

Resin-bonded bridgeOr Minimal-Preparation Bridge, consists of a

metal framework including a pontic with wing-likeextensions coming from the proximal sides.

For example; Maryland bridgeThese metal wings are prepared to have a porous surface

so that they can receive a bonding agent, and then thewings are bonded to the back sides of the teeth on either

side of the missing tooth.

Pontic

Indications for Crowns

Badly broken-down teeth.

Primary trauma.

Tooth wear.

Hypoplastic conditions.

To alter the shape, size or inclination of teeth.

To alter the occlusion.

As part of another restoration.


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Badly broken-down teeth

Teeth may have suffered secondary caries or parts of the

tooth or restoration may have broken off.Before crowns can be made, the lost dentine will usually

need to be replaced by a sui table core of restorative

material.


Primary trauma

Tooth may have a large fragment broken off without

damaging the pulp and leaving sufficient dentine tosupport a crown.


Tooth wear

The processes of erosion (damage from acid), attrition

(mechanical wear of one tooth against another) and

abrasion (mechanical wear by extraneous agents) may

occur in patients.

If tooth wear is excessive or occurs early in life, crowns or

other restorations may be needed.


Hypoplastic conditions

Can hereditary or acquired defects .

Examples of the former are amelogenesis imperfecta,

dentinogenes imperfecta and hypodontia (for example

peg-shaped upper lateral incisors).

Examples of acquired defects are fluorosis, tetracycline

stain and enamel hypoplasia resulting from a major

metabolic disturbance (usually a childhood illness at the

age when the enamel was developing).

Peg-shaped lateral incisor Amelogenesis Imperficta

Dentinogenesis ImperfictaEnamel Hypoplasia


To alter the shape, size or inclination of teeth

Minor changes in appearance of teeth can be achieved by

'crowns. Teeth can be made larger but not usually

smaller. For example. a diastema between teeth which

the patient finds unattractive can be closed by means of

oversized crowns.

Before Treatment After Treatment


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To alter the occlusion

Crowns may be used to alter the angulation or occlusal

relationships of anterior and posterior teeth as part of anocclusal reconstruction either to solve an occlusal

problem or to improve function.


As part of another restoration

Crowns are made to support bridges and as components of

fixed splints. They are also made to alter the alignmentof teeth to produce guide planes for partial dentures or to

carry precision attachments for precision attachment-

retained partial dentures.

Combined indicationsMore than one of these indications may be present, for

example, a broken-down posterior tooth that is over-

erupted and tilted may be crowned as a repair and at the

same time to alter its occlusal relationships and its

inclination , providing a guide plane and rest seat for a

partial denture.

Indications for anterior crowns

Caries and trauma.

Non-vital teeth.When a pulp becomes necrotic the tooth often discolours due to the

haemoglobin breakdown products. This discoloration may be suchthat it can only satisfactorily be obscured by a crown.

Tooth wear.

Hypoplastic conditions.

To alter the shape, size or inclination of teeth.

As part of other restorations.

The alternatives to anterior

crowns? Bleaching.Some teeth discoloured by a necrotic pulp can be bleached with

hydrogen peroxide.

Restorations with composite materials or glass

ionomer cements.It is clear that no absolute rules can be given on whether crowns or

fillings are indicated other than to say that in general the moreconservative procedures are to be preferred.

Veneer restorations.Composite or porcelain veneers can be used after simply acid etching

the enamel, or some preparation of the enamel may be first carried

out.

Indications for posterior crowns

Restoration of badly broken-down teeth.

Restoration of root-filled teeth.There is a strong clinical impression and some scientific evidence that root-filled teeth are more likely to f racture than teeth with vital pulps.

Endodontically treated teeth are thought to be more brittle because of waterloss and loss of collagen cross-linking.

Together with the original damage that necessitated the root filling and the

access cavity, follows that some thin and undermined cusps of root-filledteeth need to be protected.

This means that many, but by not means all, root-filled posterior teeth are

crowned.

To alter the occlusion.

As part of another restoration.


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The alternatives to posterior

crowns? Pin-retained amalgam restorations.

Tooth-colored posterior restorations.

Gold or ceramic inlays and onlays.

Choosing the right posterior

restorationThe decision depends upon three factors:

Appearance.

Problems of retention.

Problems of strength of the remaining tooth

tissue and the restorative material.

Can be treated with pin-retainedamalgam restoration

Can be treated with gold/ceramic inlayor GIC/Composite layered restoration

to strengthen the cusps

Can be treated with a core build-up(Composite or Amalgam) and

Partial coverage crown.

Can be treated with a core build-up(Composite or Amalgam) and

Complete coverage crown.

Indications for

fixed Prostheses (Bridges)1. Short span edentulous areas (one or two teeth).

2. Presence of sound teeth that can offer sufficient

support (abutment teeth).

3. Patients preference.

4. The patient has the skills and motivation to

maintain good oral hygiene.

5. Mentally compromised and physically

handicapped patients.

Contraindications for

Fixed Prostheses (Bridges)1. Long span edentulous spaces, bilateral edentulous

spaces, and distal extension edentulous areas.

2. Necessary supportive tissues are diseased or

missing. Suitable abutment teeth are not present.

3. Very young patients where teeth have large pulp

chambers.Construction of a definitive crown (full-veneer crown) for a tooth of a patient

under 18 years of age should be postponed until full eruption finishes to thetooth.

3. The patient is in poor health.

4. The patient is not motivated to have the prosthesis

or have poor oral hygiene habits.

5. The patient cannot afford the treatment.

HISTORY TAKING

AND

CLINICAL

EXAMINATION


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To achieve predictable success in this technically

exacting field, there must be meticulous

attention to every detail-from the initial patient

interview and diagnosis

Making the correct diagnosis is prerequisite to

formulating an appropriate treatment plan. This

requires that all pertinent information be

obtained.

HISTORY

A patient's history should include all

pertinent information concerning the

reasons for seeking treatment, along with

any personal information, including

relevant previous medical and dental

experiences.

The chief complaint

The chief complaint should be recorded,

preferably in the patient's own words.

This may be just the tip of the iceberg,

and careful examination will often reveal

problems and disease of which the patient

is unaware.

Chief complaints usually fall into one of the

following four categories:

Comfort (pain, sensitivity, swelling)

Function (difficulty in mastication or speech)

Social (bad taste or odour)

Appearance (fractured or unattractive teeth or

restorations, discoloration)

PERSONAL DETAILS

The patient's name, address, phone

number, sex, occupation, work schedule,

and marital and financial status are noted.

MEDICAL HISTORY

An accurate and current general medical

history should include any medication the

patient is taking as well as all relevant

medical conditions

If necessary, the patient's physician(s) can

be contacted for clarification.


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The following classification may be helpful:

1. Conditions affecting the treatment methodology(e.g., any disorders that necessitate the use of antibioticpremedication, any use of steroids or anticoagulants, and any

previous allergic responses to medication or dental materials).

2. Conditions affecting the treatment plan(e.g., previous radiation therapy, hemorrhagic disorders, extremes of

age, and terminal illness).

3. Systemic conditions with oral manifestations.For example, periodontitis may be modified by diabetes, menopause,pregnancy, or the use of anticonvulsant drugs.

4. Possible risk factors to the dentist and auxiliary

personnel(e.g., patients who are suspected or confirmed carriers of hepatitis B,

acquired immunodeficiency syndrome, or syphilis).

DENTAL HISTORY

Periodontal History:

The patient's oral hygiene is assessed, and

current plaque-control measures are

discussed. Any previous periodontal

surgery should be noted.

Restorative History:

The patient's restorative history may include

only simple composite resin or dental

amalgam fillings. The age of existing

restorations can help establish the

prognosis and probable longevity of any

future fixed prostheses.

DENTAL HISTORY

Endodontic History:

Patients often forget which teeth have been

endodontically treated. These can be

readily identified with radiographs.

Periapical health can be monitored and any

recurring lesions promptly detected.

DENTAL HISTORY

Orthodontic History:

Root resorption (detected on radiographs) may beattributable to previous orthodontic treatment. As the

crown/root ratio is affected, future prosthodontic

treatment and its prognosis may also be affected.

Occlusal adjustment (reshaping of the occlusal surfaces of

the teeth) may be needed to promote long-term

positional stability of the teeth and reduce or eliminate

parafunctional activity.

DENTAL HISTORY

Removable Prosthodontic History:

The patient's experiences with removable

prostheses must be carefully evaluated.

DENTAL HISTORY


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Oral Surgical History:

Information about missing teeth and any

complications that may have occurred

during tooth removal is obtained.

DENTAL HISTORY

Radiographic History:

Previous radiographs may prove helpful in

judging the progress of dental disease.

In most instances, however, a current

diagnostic radiographic series is essential

and should be obtained as part of the

examination.

DENTAL HISTORY

TMJ Dysfunction History:

A history of pain or clicking in the

temporomandibular joints (TMJs) or

neuromuscular symptoms which should

normally be treated and resolved before

fixed prosthodontic treatment begins.

DENTAL HISTORY EXAMINATION

An examination consists of the clinician's

use of sight, touch, and hearing to detect

conditions outside the normal range.

To avoid mistakes, it is critical to record

what is actually observed rather than

to make diagnostic comments about the

condition.

GENERAL EXAMINATION

The patient's general appearance is assessed.

EXTRAORAL EXAMINATIONSpecial attention is given to facial asymmetry

because small deviations from normal may hint

at serious underlying conditions.

Cervical lymph nodes are palpated, as are the

TMJs and the muscles of mastication.

Temporomandibular Joints (TMJs).

The clinician locates the TMJs by palpating

bilaterally just anterior to the auricular tragi while

having the patient open and close. This permitsa comparison between the relative timing of left

and right condylar movements during the

opening stroke.


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Tenderness, or pain on movement, is noted

and can be indicative of inflammatory

changes in the retrodiscal tissues, which arehighly vascular and innervated.

Clicking in the TMJ is often noticeable

through auricular palpation.

A maximum mandibular opening resulting in less

than 35 mm of interincisal movement is

considered to be restricted, because the

average opening is greater than 50 mm

any midline deviation on opening and/or closing isrecorded.

The maximum lateral movements of the patient

can be measured (normal is about 12 mm).

Muscles of Mastication:

The masseter and temporal muscles, as well as

other relevant postural muscles, are palpated for

signs of tenderness.

Muscle Palpation

A, Masseter.

B, Temporal muscle.

C, the trapezius muscle.

D, The sternocleidomastoid

muscle.

E, The floor of the mouth.


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Lips:

The patient is observed for tooth visibility during

normal and exaggerated smiling. This can be

critical in fixed prosthodontic treatment planning

especially for margin placement of certain metal-

ceramic crowns.

Smile analysis is an important part of the

examination

The "negative" space between the maxillary

and mandibular teeth when the patient laughs

INTRAORAL EXAMINATION

The intraoral examination can reveal considerable

information concerning the condition of the soft

tissues, teeth, and supporting structures.

The tongue, floor of the mouth, vestibule, cheeks,

and hard and soft palates are examined, and

any abnormalities are noted.

Gingiva:

The gingiva should be lightly dried before

examination so that moisture does notobscure subtle changes or detail.

Color, texture, size, contour, consistency,

and position are noted and recorded.

Periodontal Examination:

Because long-term periodontal health isessential to successful fixed

prosthodontics, existing periodontal

disease must be corrected before any

definitive prosthodontic treatment is

undertaken.


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The periodontal probe is one of the most

reliable and useful diagnostic tools

available for examining the periodontium. It provides a measurement (in millimeters)

of the depth of periodontal pockets and

healthy gingival sulci on all surfaces of

each tooth.

CLINICAL ATTACHMENT LEVEL

Documenting the level of attachment helps theclinician determine the amount of periodontal

destruction that has occurred and is essential whenrendering a diagnosis of periodontitis.

The clinical attachment level (CAL or AL) isdetermined by measuring the distance between theapical extent of the probing depth and a fixedreference point on the tooth, most commonly the

cementoenamel junction (CEJ).

CAL- Continued

When the free margin of the gingiva is located on

the clinical crown and the level of the epithelial

attachment is at the CEJ, there is no loss of

attachment, and recession is noted as a

negative number.

When the level of the epithelial attachment is on

root structure and the free margin of the gingiva

is at the CEJ, the attachment loss equals the

probing depth.

Dental Charting

An accurate charting of the state of the dentition

will reveal important information about the

condition of the teeth and will facilitate treatment

planning.

Adequate charting must show presence or

absence of teeth, dental caries, restorations,

wear faceting and abrasions, fractures, and

malformations.

Occlusal Examinat ion

Occlusal analysis should be an integral part of the

assessment of a postorthodontic dentition.

The objective is to determine to what extent the

patient's occlusion differs from the ideal and how

well the patient has adapted to this difference.

Special attention is given to initial contact, tooth

alignment, eccentric contacts, and jaw

maneuverability.

Initial Tooth Contact:

The relationship of teeth in both centricrelation and the intercuspal position should

be assessed.


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General Alignment:

The teeth are evaluated for crowding,

rotation, supra-eruption, spacing,

malocclusion, and vertical and horizontal

overlap.

Lateral and Protrusive Contacts:

The degree of vertical and horizontal overlap

of the teeth is noted.

The patient is then guided into lateralexcursive movements, and the presence

or absence of contacts on the nonworking

side and then the working side is noted.

Jaw Maneuverability:

The ease with which the patient moves the

jaw and the way it can be guided through

hinge closure and excursive movements

should be assessed.

RADIOGRAPHIC

EXAMINATION

Detailed knowledge of the extent of bone

support and the root morphology

of each abutment tooth is essential for

establishing a comprehensive fixed

prosthodontic treatment plan.

VITALITY (sensibility)

TESTING

Before any restorative treatment, pulpalhealth must be assessed, usually by

measuring the response to

percussion and thermal or electrical

stimulation.

Diagnostic CastsDiagnostic casts are an integral part of the

diagnostic procedures necessary to give the

dentist as complete a perspective as possible of

the patient's dental needs.

To accomplish their intended goal,

they must be accurate reproductions

of the maxillary and mandibular arches,

made from alginate impressions.


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To gain the most from the diagnostic casts, they

should be mounted on a semi-adjustable

articulator.

Articulated diagnostic allow an unobstructed view

of the edentulous spaces and an accurate

assessment of the span length, as well as the

occlusogingival dimension.

The length of abutment teeth can be accurately

gauged to determine which preparation designs

will provide adequate retention and resistance.

The true inclination of the abutment teeth will also

become evident, so that problems in a common

path of insertion can be anticipated.

A further analysis of the occlusion can be

conducted using the diagnostic casts.

A thorough evaluation of wear facetstheir

numbers, size, and location is possible

when they are viewed on casts.

Occlusal discrepancies can be evaluated and the

presence of centric prematurities or excursive

interferences determined.

Diagnostic the wax-up will help the dentist

plan and execute the preparations

and the interim, or provisional, restorations.

DIAGNOSIS AND

PROGNOSIS

When the history and examination arecompleted, a differential diagnosis is

made.

The practitioner should determine the

most likely causes of the observed

condition(s) and record them in order of

probability.

A typical diagnosis will condense the information

obtained during the clinical history taking and

examination.

For instance, a diagnosis could read as follows: 28-year-old male, no

significant medical history; vital signs normal. Chief complaint:

Mesiolingual cusp fracture on tooth # 46. Teeth # 18, # 16, #

17, # 38, and # 48 missing. High smile line. Caries: # 14, mesial; # 26,

distal; # 35, mesio-occlusal; and # 46, mesioocclusal-

distal. Generalized gingivitis four posterior quadrants.


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PROGNOSIS:

The prognosis is an estimation of the likely

course (outcome) of a disease.

The prognosis of dental disorders is

influenced by:

General factors (age of the patient,

lowered resistance of the oral environmentor caries risk); and

Local factors (forces applied to a given

tooth, access for oral hygiene measures,

individual tooth mobility, root angulation,

root morphology, crown-to-root ratios).

Overview of aFixed

ProsthodonticProcedures

History taking, examination and diagnosis,primary impression

. Articulated Study casts, diagnostic wax-up

Shade matching

Tooth preparation

Gingival retraction and tissue management, Finalimpression making

Bite registration

Provisional coverage (interim restoration)

Laboratory prescription

. Laboratory procedures include: definitive cast and die fabrication,wax-Up, investing and casting, porcelain build-up (for PFM

restorations)

Clinical try-in and Adjusting. Laboratory procedures include: Polishing and glazing for porcelain.

Cementation

Home care instructions

REFERENCES

Rosenstiel, S.F., Land, M.F., and

Fujimoto, J. (2006). Contemporary Fixed

Prosthodontics. 4th Ed. Mosby.

Shilingburg, H.T. (2003).Fundamentals of

Fixed Prosthodontics. 3rd Ed.

Quintessence Pub. Co.

Smith B.G. and Howe L.C.(2007).

Planning and making crowns and bridges.

4th Ed. Informa HealthCare.Dr. Maan Ibrahim Al-Marzok 2012

Documents

1. Introduction to Fixed Prosthodontics