removable partial denture principles of design

D R . M O H A MED O S M A N

B D S , G B O I , M S C

Removable Partial Denture Principles of Design

CONTENTS:

Introduction.

Factors influencing design.

Principles of Design.

Conclusion.

References.

INTRODUCTION:

The word "design" means to create according to a plan.

A removable prosthesis should be designed only when the biomechanical and functional requirements of the patient and prosthesis are understood.

The design process begins with the identification of a problem and ends with its resolution through the application of sound biomechanical concepts.

A sound understanding of the components of partial dentures, and the different potential forms for each component, is essential if dentures are to be designed appropriately for each patient.

INTRODUCTION:

FACTORS INFLUENCING DESIGN:

PRESERVATION OF TEETH AND PERIODONTAL STRUCTURES. A primary objective in design is to maintain healthy bone, teeth, and supporting soft tissue structures.

MINIMAL TOOTH AND MINIMAL GINGIVAL COVERAGE. Designs which minimize coverage of these tissues are preferred since they tend to reduce plaque accumulation.

THE NATURE OF THE SUPPORT: TOOTH BORNE OR TOOTH-MUCOSA BORNE. In the tooth-mucosa borne partial denture, consideration must be given to equitable distribution of forces between the abutment teeth and the residual (edentulous) ridge.

ANATOMIC LIMITATIONS. The presence of certain congenital or acquired anatomic features such as bony exostoses, reduced vestibular depth, undercuts, or anomalies may influence the design.

FACTORS INFLUENCING DESIGN:

TOOTH INCLINATION, POSITION, OR CONTOUR. May prevent a design feature from being utilized, dictating an alternative choice.

CONTINGENCY PLANNING. Possible future loss of teeth may require provision for modifications of the prosthesis.

FACTORS INFLUENCING DESIGN:

POTENTIAL MAGNITUDE OF APPLIED FORCES. Increased functional forces or parafunctional forces, may increase the structural requirements of the framework or require splinting of abutment teeth.

EASE OF PLACEMENT AND REMOVAL. Handicapped individuals may be limited in their ability to place and remove the partial denture.

FACTORS INFLUENCING DESIGN:

ESTHETICS. May be the most important factor from the viewpoint of the patient. May influence the type of clasps used.

DESIRES AND PREVIOUS EXPERIENCE OF THE PATIENT. The desires of the patient and the opinion of the dentist may not always be in accord. Whenever possible, acceptable options should be presented to the patient.

FACTORS INFLUENCING DESIGN:

RPD Design

The design of RPD should meet the following sequence:

1. Saddles ( Lattice or mesh).

2. Support.

3. Indirect retention.

4. Retention.

5. Bracing and reciprocation.

6. Connector (Major & Minor).

The various RPD components can be drawn in different colors to

help with identification.

RPD Design

Example :

o Class 2 ( Mandible) Class 2 mode 2 ( Maxilla)

RPD Design

Saddle ( Yellow) & Support ( Red):

RPD Design

Indirect Retainer ( Red) :

RPD Design

Retention ( Green):

RPD Design

Bracing & Reciprocation ( Blue ) :

RPD Design

Connector ( Black) :

RPD Design

Final Metal Framework :

Class II

Class I

Class III

Class IV