Fixed Partial Dentures 2

FIXED PARTIAL DENTURES.(Crown & Bridges)

Definition.The prosthesis which is cemented to the abutment

and cannot be removed by the patient.

History taking: Collecting the information which are important in treatment planning and diagnosis of the disease.

FPDs

Chief complaint usually falls into one of the following four categories:a. Comfort( pain, sensitivity, swelling).b. Function(difficulty in mastication or speech)c. Social(bad taste or odor)d. Appearance( fractured or unattractive teeth or restorations, discoloration)

CHIEF COMPLAINT.

It consists of clinical use of sight, touch, and hearing to detect conditions outside the normal range.

It is critical to record what is actual observed rather than to make diagnostic comments about the condition.

For example, ”swelling” “redness” and “bleeding on probing of gingival tissue” should be recorded rather than “gingival inflammation”(which implies a diagnosis).

EXAMINATION

General Examination. Extra Oral Examination.

a. TMJb. Muscles of mastication c. Lips

EXAMINATION

Intraoral Examination:a. Periodontal information1. Gingiva.

2. Periodontium.

3. Occlusal examination

EXAMINATION

Radiographic examination.

(X-ray)

EXAMINATION

Approach should be logical and systematic.

DIAGNOSIS & PROGNOSIS

After completion of history and examination a differential diagnosis is made.

A definitive diagnosis can usually be developed after such supporting evidence has been assembled.

DIFFERENTIAL DIAGNOSIS

Prognosis is an estimation of the likely course of a disease.

PROGNOSIS

General Factorsa. Overall caries rate.b. Diabetesc. Bite force of the patient. d. others.

PROGNOSIS

Local factors:a. Vertical overlap of the anterior teeth.b. Impaction adjacent to molar that will be crowned

may pose a serious threat in a younger individual in whom additional growth can be anticipated but it may be of lesser concern in an older individual.

PROGNOSIS

c. Individual tooth mobility.d. Root angulation.e. Root morphology.f. Crown-root ratio.g. Others

PROGNOSIS

Material used Model making Articulation ( non-adjustable, semi-adjustable)

DIAGNOSTIC CAST.

IDENTIFICATION OF THE PATIENT’S NEEDS. Successful treatment planning is based on proper

identification of the patient’s needs “Ideal” treatment against the patient's needs is usually a

failure.

TRETMENT PLAINING.

“Ideal” treatment against the patient's needs is usually a failure.

Correction of Existing Disease. Prevention of Future Disease. Restoration of function. Improvement of Appearance.

TREATMENT PLANNING.

All existing restorative materials and techniques have limitations and cannot exactly match the properties of a natural tooth structure.

MATERIALS USED

Whenever possible, FPDs should be design as simple as possible with a single well anchored retainer fixed rigidly at each end of the pontic.

Teeth in which pulpal health is doubtful should be endodontic ally treated before the initiation fixed prosthodontics.

SELECTION OF ABUTMENT TEETH.

Unrestored abutments: An unrestored caries free tooth is an ideal abutment.

Mesially Tilted Second Molar: Overloading of the abutment teeth should be

avoided.

SELECTION OF ABUTMENT

The occlusal forces should be directed along the long axis of the tooth.

Root surface area. Ante’s law: Root surface area of the abutments

supported by bone should be equal or more than the root surface area of the teeth which are being replaced.

DIRECTION OF FORCES

Nayman and Ericsson, however cast doubt on the validity of Ante’s law by demonstrating that teeth with considerably reduced bone support can be successfully used as fixed partial denture abutments.

ROOT SURFACE AREA.

ORAL SURGERY PERIODONTICS ENDODONTICS ORTHODONTICS FIXED PROSTHODONTICS REMOVABLE PROSTHODOTICS

SEQUENCE OF TREATMENT

A foundation restoration, or , core, is used to build a damaged tooth to ideal anatomic form before it is prepared for a crown.

FOUNDATION RESTORATIONS

Materials used:

1. Dental Amalgam.2. Glass Ionomer.3. Composite Resin.4. Pin-retained cast metal core.

FOUNDATION RESTORATION

1. BIOLOGICAL CONSIDERATIONS. Affect the health of the oral tissues.

2. MECANICAL CONSIDERATIONS. Affect the integrity and durability of the restoration.

3. ESTHETIC CONSIDERATION. Affect the appearance of the patient.

PRINCIPLES OF TOOTH PREPARATION

PREVENTION OF DAMAGE DURING TOOTH PREPARATION: 1. Adjacent teeth. 2. Soft tissues. 3. Pulp

BIOLOGICAL CONSIDERATIONS

CAUSES OF INJURIES: 1. Temperature. 2. Chemical Action. 3. Bacterial Action.

BIOLOGICAL CONSIDERATIONS

Conservation of Tooth Structure. Considerations Affecting Future Dental Health. 1. Axial reduction. 2. Margin Placement. 3. Margin Adaptation. 4. Margin Geometry. 5. Occlusal Consideration. 6. Preventing Tooth Fracture.

BIOLOGICAL CONSIDERTION

Retention Form. The quality of a preparation that prevents the restoration from becoming dislodged by such forces parallel to the path of withdrawal is known as retention.

MECHANICAL CONSIDERATIONS

Factors Affecting retention Form.

1. Magnitude of dislodging forces. 2. Geometry of the tooth preparation. 3. Roughness of the fitting surface of the restoration. 4. Material being cemented. 5. Film thickness of the luting agent.

MECHANICAL CONSIDERATIONS.

Resistance Form. The quality of preparation that prevents the restoration from becoming dislodged by such forces as horizontal or oblique which is applied during mastication and par functional activities.

MECHANICAL CONSIDERATIONS.

Factors affecting resistance form.

1.Magnitude and direction of the dislodging forces. 2. Geometry of the tooth preparation. 3. Physical properties of the luting agent.

MECHANICAL CONSIDERATIONS

Factors affecting esthetic considerations.

1. Metal- Ceramic Restoration. 2. Facial Tooth Reduction. 3. Incisal Reduction. 4. Proximal Reduction. 5. Labial Margin Placement.

ESTHETIC CONSIDERATIONS.

Quality is never an accident; it is always the result of high

intention, sincere effort, intelligent direction and skillful execution; it

represents the wise choice of many alternatives. - William Foster

Advantages.

1. Greater retention. 2. Greater resistance. 3. Superior strength. 4. Modification in tooth structure can be done.

COMPLETE CAST CROWNS.

Disadvantages.

1. Extensive reduction of tooth structure. 2. Gingival inflammation. 3. Esthetics problems 4. Thermal/vitality test is difficult in complete crown.

COMPLETE CAST CROWNS

INDICATIONS:

1. Extensive coronal destructive teeth( caries or trauma).

2. Where maximum retention and resistance are required.

3. Short clinical crowns. 4. Where high displacing forces are anticipated.

COMPLETE CROWNS

5. Correction of axial contour of a tooth. 6. Endodontically treated teeth. 7. Congenitally malformed teeth. 8. Discolored teeth.

COMPLETE CROWNS.

CONTRAINDICATIONS:

1. In case where treatment objective can be achieved without crown.

2. Where light support is needed( cantilever bridge.) 3. If a high esthetic need exists as in anterior teeth.

COMPLETE CROWNS.

STEPS OF CROWN PREPARATION:

Occlusal guiding grooves. Occlusal reduction. Axial alignment grooves. Axial reduction. Finishing and evaluation.

CROWN PREPARATION

INDICATIONS.

In posterior teeth where moderate amount of tooth structure is lost, provided the buccal wall is intact.

Used as a retainer for fixed partial denture(bridge). Where alteration in the occlusal surface is needed.

THE PARTIAL VENEER CROWN

CONTRAINDICATIONS.

On teeth that have short clinical crowns. As retainers for long span bridges. For endodontically treated teeth. In patients with active caries and periodontal diseases. In malshaped and poorly aligned teeth.

THE PARTIAL VENEER CROWNS

Conservation of the tooth structure. Reduce the risk of pulpal and periodontal damage. Supragingival finishing lines are easily approached. Better oral hygiene can be maintained. As the margins of the restoration are usually away

from the gum margins, less chances of gingivitis.

ADVANTAGES

Cementation is easy. Vitality test can be done after cementation.

ADVANTAGES

Less retention. Less resistance. Preparation is difficult.

DISADVANTAGES

Complete ceramic crowns should have even thickness circumfrentionaly.

Usually about 1 to 1.5mm is needed to create an esthetically pleasing restoration.

Incisally, a greater ceramic thickness may be required.

COMPLETE CERAMIC CROWNS.

ADVANTAGES.

Superior in esthetics. Excellent translucency.(Natural look). Good tissue response. Slightly more conservative tooth reduction in

preparation.


DISADVANTAGES.

Reduced strength due to absence of metal substructure. For shoulder preparation significant proximal tooth

reduction is required. The preparation should provide support for the

porcelain along its entire incisal edge. Thus a severely damage tooth should not be restored with a ceramic crown.


As a retainer for FPDs, all ceramic crowns are not effective.

Connectors require large cross section, as the material is brittle, this leads to gum impingement and periodontal failure.

DISADVANTAGES cont.………..

INDICATIONS:

In areas with high esthetic requirements.


CONTRAINDICATIONS:

When more conservative restoration can be used. Rarely are they indicated for molar teeth. Increased occlusal load and decreased esthetic demand.

COMPLETE CERAMIC CROWNS

The tooth should be assessed for the following points; 1. Apical seal. 2. Tenderness. 3. Exudate. 4. Fistula. 5. Active inflammation.

RESTORATION OF ENDODONTICALLY TREATED TEETH

IN SEVERELY DAMAGED TEETH. Post-and-core. In one piece. In separate pieces. One piece post crowns. (Not common) Two step technique,

( Post-and-core foundation and separate crown.)

Endodontically treated teeth cont.…

THE AMOUNT OF REMAINING TOOTH SRUCTURE IS PROBABLY THE SINGLE MOST IMPORTANT PREDICTOR OF CLINICAL SUCCESS.

Endodotically treated teeth cont.….

ANTERIOR TEETH. Dislodgement of a retained anterior crown is frequently

seen clinically and results from inadequate retention form of prepared root.

Post retention is affected by:1. Preparation Geometry.2. Post length.3. Diameter

RETENTION FORM

5. Surface Texture 6. Luting agent.

Post retention affected by……….

Prefabricated Post.(available in different materials) Custom made posts.

POST FABRICATION

CROWNS:

Extracoronal Restoration.

It protects the underlying tooth structure.

It restore the function.

Restore aesthetics.

TERMS USED IN FPDs

Clinical Crown: It is intraoral visible tooth structure.

Anatomical Crown: The area of tooth covered by enamel.

Artificial Crown. a. Full veneer crown.(FVC) b. Partial veneer crown(PVC)

Types of Crowns

RETAINERS: Part of FPD which is used as a support and cemented to the natural tooth or implant.

ABUTMENT: may be tooth, root or implant.

TERMS USED IN FIXED PARTIAL DENTURES.

PONTIC: The artificial tooth that replaces a missing tooth in

FPD.

CONNECTORS: It is the connection that exists between the retainer

and pontic.

TERMS USED IN FPDs.

SHORT SPAN EDENTULOUS AREA.

PROPER SUPPORT.

PATIENT’S PREFERANCE.

PATIENTS WHICH CANNOT MAINTAIN RPDs.

INDICATIONS FOR FPDs

LARGE AMOUNT OF BONE LOSS.

VERY YOUNG PATIENTS.

PERIODONTALLY COMPROMISED TEETH.

LONG SPAN EDENTULOUS AREAS.

CONTRAIDICATIONS FOR FPDs.

UNCOPERATIVE PATIENTS.

MEDICALLY COMPROMISED PATIENTS.

VERY OLD PATIENTS.

Distal extension denture bases as in class I, II.

CONTRAINDICATIONS FOR FPDs.

Three major classes.

Each class is divided into three divisions.

Each division is further divided into four subdivisions.

CLASSIFICATION OF FPDs.

CLASS:

It identify the location of the edentulous space.

CLASS I:

Posterior edentulous space(Molar or premolar)

CLASSIFICATIONS OF FPDs.

CLASS II:

Anterior edentulous spaces( Incisors or Canines are missing)

CLASS III:

Antero-posterior edentulous spaces.


DIVISION: A division gives information about the abutment

teeth.

DIVISION I: Cantilever FPDs. Abutment on one side.


DIVISION II: Conventional FPDs, abutments on both sides of the

edentulous area.

DIVISION III: Pier Abutments. A single tooth is surrounded by an

edentulous space on either side.


Sub-division: A sub-division denotes the status of the tooth that is

to be used as an abutment.

Sub-division I:

Ideal abutments. Healthy teeth which provide good support.


Sub-division II:

Tilted Abutment.(Either the design of the prosthesis is to be modified or the tilt should be corrected).

Sub-division III: Periodontally weak abutment.


Sub-division IV:

Extensively damaged abutment.

Sub-division V:

Implant abutment.

CLSSIFICATION OF FPDs.

DEPENDING ON THE TYPE OF CONNECTOR:

Fixed fixed partial denture.

Fixed movable partial denture.

Removable fixed partial denture.


DEPENDING ON MATERIAL USED.

All metal Metal ceramic All ceramic All acrylic.


LENGTH OF SPAN:

Short span bridges.

Long span bridges.

CLASSIFICATION OF FPDs

DURATION OF USE.

Permanent fixed PDs

Interim bridges.


TYPES OF ABUTMENTS:

Normal/ Ideal abutment. Cantilever abutment. Pier abutment. Mesially tilted. Endodontically treated abutment. Implant abutment.

CLASSIFICATION FOR FPDs.

Retainer is a crown or any part of FPD that is cemented to the abutment.

1. Major retainers( FVC,PVC.) which covers the whole occlusal surface of the abutment.

2. Minor retainers. It a small extension that is cemented on to the tooth.

RETAINERS

BASED ON TOOTH COVERAGE:

Full veneer retainers.

Partial veneer retainers.

Conservative retainers. ( Minimal preparation)

TYPES OF RETAINERS.

BASED ON THE MATERIAL BEING USED.

All metal

Metal ceramic

All ceramic

All acrylic.

TYPES OF RETAINERS.

It is an artificial tooth on a fixed partial denture that replaces a missing tooth, restores its functions and usually fills the space.

PONTIC.

1. It should restore the functions of a tooth it replaces. 2. It should provide good aesthetics. 3. It should be comfortable to the patient. 4. It should be biocompatible. 5. It should be easy to clean. It should preserve the underlying mucosa and bone.

REQUIREMENTS OF A PONTIC

FACTORS AFFECTING THE DESIGN OF A PONTIC.

1.Space available for the placement of pontic.

2. The contour of the residual alveolar ridge.

3. The amount of occlusal load that anticipated for that patient.

PONTIC DESIGN.

Siebert’s Classification of Ridge defects.

CLASS I defects: Normal faciolingual width with normal height.

CLASS II defects: Loss of ridge height with normal width.

CLASS II defects: Loss in both dimensions.

RESIDUAL RIDGE CONTOUR

A. Based on Mucosal contact.

B. Type of material used.

C. Method of fabrication.

CLASSIFICATION OF PONTICS.

TISSUE SURFACE IN CONTACT. 1.RIDGE LAP/Saddle 2. MODIFIED RIDGE LAP 3. OVATE 4. CONICAL TISSUE SURFACE NOT IN CONTACT. 1. SANITARY/Hygienic 2. MODIFIED SANITARY.

PONTICS DESIGNS BASED ON THE MUCOSAL CONTACTS.

SADLE OR RIDGE LAP: Concave fitting surface Overlap the residual ridge buccolingually.

SHOULD BE AVOIDED Concave surface of the pontic is inaccessible. Cause tissue inflammation.

TISSUE SURFACE IN CONTACT.

MODIFIED RIDGELAP PONTIC:

Combines best features of the Hygienic and Saddle pontic designs.

Combining esthetics and easy cleaning.


CONICAL PONTIC: Also called Egg-shaped, Bullet-shaped, or Heart-

shaped. It only touches the residual ridge at one point. Easy to clean. Recommended in posterior teeth where esthetics is a

less concern.


OVATE PONTIC: Esthetically superior. Its convex tissue surface reside in the soft tissue

depression. Socket preservation techniques are necessary for

successful results.


Ridge contact: The contact between the underlying tissues and pontic

should be pressure free. Oral Hygiene Consideration: Pontic Material: It should provide good aesthetics. It should be biocompatible. It should withstand occlusal forces.

REQUIREMENTS OF TISSUE SURFACE OF PONTICS.

Sanitary or Hygienic Pontic. Tissue surface remains clear of the residual ridge. Easy plaque control. Only in posterior teeth.

TISSUE SURFACE NOT IN CONTACT

Metal-ceramic Pontics All metal pontic All ceramic pontic Resin pontic

BASED ON MATERIAL

Custom-made pontics.

Prefabricated pontics

BASED ON METHOD OF FABRICATION

The portion of the Fixed Partial Dentures that unites the retainer(s) and pontic(s).

CONNECTORS.

Rigid connectors

Non-rigid connectors.

TYPES OF CONNECTORS.

Used to unite the retainers with pontics in Fixed-fixed partial dentures.

These connectors are used when the load is transferred directly from the pontics to the abutments.

RIGID CONNECTORS.

Cast rigid connectors(conventional bridges)

Soldered rigid connectors.

RIGID CONNECTORS

Used in situation where single path of insertion cannot be achieved due non parallel abutments.

These types of connectors allow limited movement between the retainer and pontics.

Non-Rigid Connectors.

Tenon Mortise connectors(TMC) /Dovetail connectors.

Mortise(female) prepared within the connectors of the retainers.

Tenon(male) attached to the pontic.

Non-Rigid Connectors

Used to maintained an existing diastema.

The connector consists of a loop on the lingual/palatal surface.

Loop Connectors.

Definition: It is the static relationship of the opposing teeth.

Centric occlusion: Occlusion of the opposing teeth when the mandible

is in centric relation. This may or may not coincide with maximum

intercuspation.

Occlusion in Fixed Partial Dentures

Maximum intercuspation:

The complete intrcuspation of the opposing teeth independent of the condyle position.

Eccentric occlusion:

OCCLUSION

Ideal requirements of the impression material used in fixed partial dentures.

Dimensional stability and accuracy Elasticity after cure. Flow. Wettability. Compatibility.

IMPRESSION MAKING IN FPDs

Elastomeric impression material.

Two stage technique

Primary impression in putty.

Secondary impression in wash.

Putty wash impression

Treatment planning.

Case selection

Case design

Ante’s Law

Causes of Misfit/mismatch crowns and bridges

Preparation

Selection of Impression material

Impression technique

Recording the fine details

Pouring the cast

Shade selection

Corresponding with the laboratory.

Demands and specific details.

Proper Wax up.

Investment

Casting Recovery and finishing. Porcelain work Firing Shade and glaze

Intraoral adjustment

Cementation

Follow up and maintenance.

Tips & Warnings

After mixing, turn the rubber mixing bowl upside down. If the dental stone mixture does not drip to the ground, then you have the appropriate consistency. If the dental stone mixture drips to the ground, there is too much water in the mixture and more dental stone will need to be added.

Air bubbles will distort the accuracy of the dental stones.

Avoid over-vibrating the dental stone mixture.

Over-vibrating will create unnecessary air bubbles.

Tips of warnings.

During the setting time period, the stone undergoes an exothermic reaction, releasing heat.

Do not separate the model from the impression until the model feels cold.

Leave the dental stone model undisturbed for 45 to 60 minutes until the material completely sets

Tips of warnings.

After setting remove the cast carefully.

Check the prepared surface for bubbles and deficiencies.

Outline the prepared margins.

Apply hardener on the prepared surfaces.( Dural)

Wax up with blue/pink wax

LABWORK OF CROWN & BRIDGE

Definition:Its a channel through which molten alloy can reach the mold in an invested ring after the wax has been eliminated. Role of a Sprue: Create a channel to allow the molten wax to escape from the mold. Enable the molten alloy to flow into the mold which was previously occupied by the wax pattern

SPRUES

FUNCTIONS OF SPRUE 1 . Forms a mount for the wax pattern . 2 . Creates a channel for elimination of wax . 3 .Forms a channel for entry of molten metal 4 . Provides a reservoir of molten metal to

compensate for the alloy shrinkage

SPRUES

SELECTION OF SPRUE1 . DIAMETER :It should be approximately the same size of the thickest portion of the wax pattern .Too small sprue diameter suck back, results porosity.

2 . SPRUE FORMER ATTACHMENT :Sprue should be attached to the thickest portion of the wax pattern .It should be Flared for high density alloys & Restricted for low density alloys

SPRUES

3 . SPRUE FORMER POSITIONBased on the1 .Individual judgment .2 .Shape & form of the wax pattern .Patterns may be sprued directly or indirectly ..Indirect method is commonly usedReservoir prevents localized shrinkage porosity .Reservoir And Its Location

SPRUES

Armamentarium : 1. Sprue . 2 . Sticky wax . 3 . Rubber crucible former . 4 . Casting ring . 5 . Pattern cleaner . 6 . Scalpel blade & Forceps . 7 . Bunsen burner

TYPES OF SPRUESI . - Wax .

II . Solid Plastic . III. Hollow Metal.

SPRUES

WETTABILITYTo minimize the irregularities on the investment & the casting a wetting agent(SURFACTANT) can be used .

FUNCTIONS OF A SURFACTANT.1 . Reduce contact angle between liquid & wax surface .2 .Remove any oily film left on wax pattern

PREREQUISITES Wax pattern should be evaluated for smoothness ,

finish & contour . Pattern is inspected under magnification & residual

flash is removed

CRUCIBLE FORMER

It serves as a base for the casting ring during investing .Usually convex in shape.May be metal , plastic or rubber .Shape depends on casting machine used .Modern machines use tall crucible to enable the pattern to be positioned near the end of the casting machine .

CASTING RING LINERSMost common way to provide investment expansion is by using a liner in the casting ring .Traditionally asbestose was used .Non asbestose ring liner used are :1) Aluminosilicate ceramic liner .2) Cellulose paper liner

Purpose of Casting Ring LinerRinger liner is he most commonly used technique to provide investment expansion. To ensure uniform expansion , liner is cut to fit the inside diameter of the casting ring with no overlap. Thickness of the liner should not be less than approximately 1mm. Place the liner somewhat short of the ends of the ring, 3mm, tends to produce a more uniform expansion, therefore less chance for distortion of the wax pattern & mold

CASTING CRUCIBLESFour types are available ;1) Clay .2) Carbon .3) Quartz .4) Zirconia –Alumina

Remove the whole wax pattern along with the sprues very carefully.

Attach the wax pattern and sprues on the crucible former in such a way that the whole complex should be accommodated in the casting ring.

Put the insulating sheet within the casting ring so that heat loss is prevented during shifting of the ring from the furnace to the casting machine.


After putting the casting ring over the wax pattern, the margins of the ring are properly sealed with modeling wax so that investment plaster should not come out of the ring.

A SURFACTANT solution is applied to prevent bubble formation during pouring.

The ring is then poured with investment plaster.


During the pouring vibrator is being used.

Leave the plaster to cool at room temperature for about 45minutes to 1hour.

Put the casting ring in the oven for about 1hour and 30minutes and raise the temperature up to 1100 degrees cent.


Melt the alloy in casting machine.

Take out the RED HOT ring from the oven and put it in the Casting machine.

Now the red hot ring is transferred from the oven to the casting machine.


Centrifuge it in the casting machine.

Now the casting is completed.

Cool it down at room temperature.

Recover the framework from the investment plaster.


Cut all the sprues.

Remove the plaster.

Blast the framework in the blasting machine.

Finish the metal with burs.


Do the final blasting on all the surfaces except the inner surfaces of the retainers/crowns.

A thin layer of thin mix porcelain is applied with brush on all surfaces which will be covered with porcelain.

This is called wash core.


After application of the wash core firing is done according to the specific programme.

The temperature of the wash core is raised up to 950 degrees instead of 930 degrees which is meant for porcelain body.

After firing the wash core in furnace the bridge is cool down.


Then opaque layer is applied and the bridge is fired in furnace again.

The bridge is cool down at room temperature.

Apply the body, cervical and incisal shades and put it in furnace for another required programme and raise the temperature up to 930 degrees.


Cool down the bridge and finish the surfaces with burs, discs, wheels.


After finishing , apply the glaze powder and put it in furnace .

Preheat for three minutes, then increase the temperature up to 930 degrees in five minutes and hold at 930 degrees for 1 minute.


If minor changes in shade are required, it can be done at this stage.

Copyright © 2006 Thomson Delmar Learning. ALL RIGHTS RESERVED.142

Part A: Types of Fixed Prosthodontics

Purpose of Prosthodontics

Restore masticatory function

Improve appearance

Improve speech

Promote good oral hygiene

Stabilize arch and occlusion

Copyright © 2006 Thomson Delmar Learning. ALL RIGHTS RESERVED.

143

Contraindications for a Fixed Prosthesis

Lack of supporting alveolar bone

Presence of periodontal disease

Excessive mobility of abutment teeth

Lack of patient interest in oral hygiene

Patient cannot afford treatment

Copyright © 2006 Thomson Delmar Learning. ALL RIGHTS RESERVED.

144

Types of Fixed Prostheses

Porcelainveneers

Directresin

veneers

Indirectresin

veneers Bridges

Onlays

Partialcrown

Full-castcrown

Fixed prostheses

Inlays

Copyright © 2006 Thomson Delmar Learning. ALL RIGHTS RESERVED.145

Materials Used for Fixed Prostheses

Compositeresin

Porcelain

Porcelainfused to metal

Goldalloy

Copyright © 2006 Thomson Delmar Learning. ALL RIGHTS RESERVED. 146

Retention of Restorations

• Core buildup– Recreation of lost tooth structure

• Retention pins– Screwed into dentin– Hold core filling material

• Post and core– After root canal therapy– Strengthens tooth


The Dental Laboratory

• Dental lab technician– Fabricates restoration– Makes die from impression– Creates wax pattern on die – Invests wax and casts invested material into

metal– Prepares metal for porcelain layers– Finishes and polishes final restoration


Selecting a Tooth Shade

• Before preparation• Moisten shade guide• Match to natural teeth

under natural light• Record in patient’s

chart• Record on lab

prescription


Tissue Retraction

• Placed in gingival sulcus

• Mechanical and chemical retraction

• Prevents bleeding• Ensures

impression of gingival margin


Provisional Restorations

Temporary coverage to protect toothbetween appointments

Fit gingival margin snugly

Protect gingiva and interproximal areas

Stabilize contacts and occlusion

Esthetics and patient comfort


The Laboratory Prescription

Descriptionof prosthesis

Dentist’sinformation

Date requested

Materialsfor prosthesis

Patient’s name

Toothshade


Crown Cementation

• Check fit–Margin–Contacts–Occlusion

• Adjust if necessary• Permanent cement


Fixed Prostheses Maintenance

• Crowns• Bridges• Dental

implants Antimicrobial

rinses

Waterirrigators

Interproximalbushes

Dental floss

Threadingsystems

Toothbrush

Plaqueremoval

Fixed Partial Dentures 2

Documents

fixed partial

fixed partial

provide good

endodontically

provide investment

red hot ring

complete ceramic

dental stone