fixed prosthodontics

Fixed

Prosthodontics
UNIVERSITY OF MOSUL
COLLEGE OF DENTISTRY
By:
Assist.Prof. Nawal Atiya Al-Sabawi

2020-2021

Department of
Conservative Dentistry

5th. YEAR

Advantages and Disadvantages of Fixed Prosthodontics

Advantages of fixed prosthodontics treatments:
• Restore function and mastication.
• Restore esthetics.
• Maintain health and integrity of dental arch.
• Support the treatment of the problem related to TMJ.
• Speech
• Periodontal splint
• A feeling of completeness
• Orthodontic retention
• Occlusal stability
• Restoring occlusal vertical dimension
Disadvantages of fixed prosthodontics treatments:
• Damage to tooth and pulp
• Secondary caries
• Failure

• Crowns

Crown: it is a fixed extracoronal restoration that restores missing tooth structure by surrounding most or all the remaining structure with material such as cast metal, ceramic, or a combination of materials such as metal and ceramic.



Full veneer crown: is an extracoronal restoration that involves all of the surfaces of clinical crown of the tooth.

• Types of crown

Partial veneer crown: is an extracoronal restoration that cover some of the tooth crown and leaving the other intact such as (3\4)three –quarter crown, 7/8 crown, pin ledge and others.

• Types of crown

Laminate veneers (type of partial veneer): is a conservative method of restoring the appearance of discolored, pitted, or fractured anterior teeth. It consists of bonding thin ceramic laminates onto the labial surfaces of affected teeth.

What is the difference between laminate and lumineer?????

• Types of crown

• Complete replacement (Post crown): It replaces the natural crown entirely. This type of crown retains itself by means of a dowel (post) extended inside the root canal space of the tooth such as a post crown.

• Bridges

Bridge (Fixed Partial Denture): is an appliance replacing one or more teeth that cannot be removed by the patient.

Definitions of Terminology

• An abutment is a tooth to which a bridge (or partial denture) is attached.
• A retainer is a crown or other restoration that is cemented to the abutment. The terms ‘retainer’ and ‘abutment’ should not be confused or used interchangeably.
• A pontic is an artificial tooth as part of a bridge.
• A span is the space between natural teeth that is to be filled by the bridge.
• A pier is an abutment tooth standing between and supporting two pontics, each pontic being attached to a further abutment tooth.
• A unit, when applied to bridgework, means either a retainer or a pontic. A bridge with two retainers and one pontic would therefore be a three-unit bridge.
• A connector (or joint) connects a pontic to a retainer, or two retainers to each other. Connectors may either be fixed or allow some movement between the components that they join.

Pier abutment

Comparison of Bridge with Removable Partial Denture

Fixed partial denture
Removable partial denture


Posterior spans 2 or fewer incisors 4 or fewer
Posterior spans longer than abutment teeth
Anterior spans longer than abutment teeth
Span length
Usually has distal abutment
but can be used with short
cantilever pontic
No distal abutment
Multiple or bilateral edentulous spaces
Span configuration
Less than 25° inclination can
be accommodated by
preparation modification
Tipped abutments can be tolerated
Widely divergent abutment alignment
Abutment alignment
Good if abutments need crowns
Non vital teeth can be used if there is sufficient coronal tooth structure
Short clinical crowns
Insufficient abutments
Abutment condition
Favourable loading (magnitude,
direction, frequency, duration]
More adaptable to irregularities in
a healthy opposing natural dentition
occlusion
Good alveolar bone support
No mobility
Can use alternate (secondary abutments) when primary abutments are weakened
Periodontal condition
Moderate resorption
No gross soft tissue defects
Gross tissue loss in residual ridge
Ridge form

• UNIVERSITY OF MOSUL

• COLLEGE OF DENTISTRY
• 020-2021
• Components of
• Bridge

Connector

Pontics
Retainers





• Retainers
Retainers are divided into two types:
Major retainers (Full veneer crown) These retainers cover all the five surfaces of the abutment. They are fabricated like a cap and are usually indicated for extensively damaged teeth. They are the most retentive and ideal retainers because their design can resist masticatory forces in all directions.
Minor retainers (Partial veneer crown) A minor retainer may be a partial crown, or a two- or three-surface inlay without full occlusal protection, Minimal-preparation minor retainers are also used for minimal preparation bridges (resin bonded bridge) where the occlusion is favorable.
Major or minor all fixed-fixed, cantilever and spring cantilever bridges have only major retainers. Fixed-movable bridges have a major retainer at one end of the pontic and a minor retainer (carrying the movable joint) at the other.

Minor retainer

• Retainers
The criteria for selecting a particular retainer will include:
• Alignment of abutment teeth and retention
• Appearance
• Condition of abutment teeth
• Conservation of tooth tissue
• Occlusion
• Cost

• Retainers

• Alignment of abutment teeth and retention:
When the abutment teeth are less paral­lel to each path of insertion:
• They could not be made independently retentive without one or other of the teeth being devitalized. This is sometimes necessary, but it is a very destructive approach.
• The solution will usually be to employ a minimal preparation bridge or a design other than fixed-fixed so that the teeth do not have to be prepared parallel to each other.
• When it is necessary to reduce a retentive feature, for example to over-taper a preparation to provide a single path of insertion with another preparation, it is advisable to add some further retentive feature such as grooves or a pin.

• Retainers

Appearance: In some cases a complete crown will have a better appearance, in some a partial crown, and in others a minimal-preparation retainer.
Condition of abutment teeth: Frequently a minimal-preparation or partial crown retainer cannot be used because of the presence of caries or large restorations involving the buccal surface, or because of the loss of the buccal surface from trauma or other cause. In these cases a complete crown retainer is chosen.
•

• Retainers

Conservation of tooth tissue:
• Buccal/facial surface should be conserved. Therefore, Partial veneer crowns are more conservative than full crowns. However, if there are sound indications for a complete crown, the operator should not allow his or her clinical judgments to be influenced by an overprotective attitude to dental enamel.
• All ceramic crowns are the least conservative.
•

• Retainers

Occlusion: In some cases the abutment teeth are sound but there is insufficient space for a minimal-prepa­ration retainer. The choice therefore is between creating space by reducing the oppos­ing teeth, moving the abutment teeth orthodontically or a combina­tion of these approaches. If none of these methods are acceptable then a conventional retainer will be necessary.
Cost: Partial crowns and complete metal crowns may be less expensive than metal-ceramic crowns, minimal-preparation retain­ers are the least expensive, and All ceramic crowns are the most expensive.
•

• UNIVERSITY OF MOSUL

• COLLEGE OF DENTISTRY
• 020-2021
• Types
• of Connectors


RIGID CONNECTORS: 1- Cast Connectors
2- Soldered Connectors
NONRIGID CONNECTORS
•

Connectors

• Connectors

RIGID CONNECTORS:
Rigid connectors must be shaped and incorporated into the wax pattern after the individual retainers and pontics have been completed to final contour but before reflowing of the margins for investing.
Cast connectors: Connectors to be cast are also waxed on the master cast before reflowing and investing of the pattern. The presence of a cast connector makes the latter somewhat more awkward. Access to the proximal margin is impeded, and the pattern cannot be held proximally during removal from the die. Restricting cast connectors to complete coverage restorations is therefore advisable. Cast connectors are more stronger than soldered connectors and decrease laboratory procedures.
•

• Connectors

Soldered Connectors: As with cast connectors, connectors to be soldered are waxed to final shape but are then sectioned with a thin ribbon saw. therefore, when the components are cast, the surfaces to be joined will be flat, parallel, and a controlled distance apart (0.25 mm). This allows accurate soldering with a minimum of distortion. They are used if the pontics and retainers have to be made separately. This is necessary when they are made of different materials, for example a complete gold crown retainer with a metal-ceramic pontic.
Soldering Gap Width:
• As gap width increases, soldering accuracy decreases.
• Extremely small gap widths can prevent proper solder flow and cause the joint to be incomplete or weak.
• Therefore, an even soldering gap of about 0.25 mm is recommended.

• Connectors

Nonrigid connectors: They are indicated when it is not possible to prepare two abutments for an FPD with a common path of placement. Segmenting the design of large, complex FPDs into shorter components that are easier to replace or repair individually is advisable.
The design of nonrigid connectors that are incorporated in the wax pattern stage consists of a mortise (also referred to as the female component) prepared within the contours of the retainer and a tenon (male) attached to the pontic, The retainers are then cast separately and fitted to each other in metal.

•

• Connectors

•

Design of Connectors:

• Size: Connectors must be sufficiently large to prevent distortion or fracture during function. but not too large to prevent interference with plaque, periodontal tissue disturbance over time.
• Shape: The shape of the tissue surface of the connector should be curved faciolingually and highly polished and smooth to facilitate cleaning and should be satisfied with the appearance.
• Position: The location of the contact area should be established correctly to influence the success and stability of the prosthesis. In the anterior teeth, the connector should place lingually. In the posterior teeth, located in the occlusal third of the crown and more lingually.

UNIVERSITY OF MOSUL

COLLEGE OF DENTISTRY

Thank You

2020-2021