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RPD LEC.3 | PROSTHODONTICS | 22-10-2018

Components of RPD3RD GRADE

LEC 3

DR. LUMA NASSRAT

ASSISSTANT LECTURER, DEPARTMENT OF PROSTHODONTICS

COLLEGE OF DENTISTRY

TIKRIT UNIVERSITY

Components of RPDs

1. Major connectors.

2. Minor connectors.

3. Rests.

4. Direct retainers.

5. Indirect retainers (if prosthesis has distal extension).

6. Denture Base.

1. Major Connectors. (maxillary & mandibular)

• Major connector is a component of the PD which connects all parts of

the prosthesis directly or indirectly.

• It provides the cross-arch stability to help resist displacement by

functional stresses.

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FUNCTION:

• Unification of the major parts of the prosthesis.

• Distribution of the applied force throughout the arch to selected teeth

and tissue.

• Cross-arch stability. Cross-arch tooth contact is effective when a rigid

major connector joins the portion of the prosthesis receiving the function

to selected regions of the arch. A rigid major connector will limit

movement possibilities by acting as a counteracting lever.

2. Minor Connectors:

• Rigid components that link between the major connector or base of RPD

and other components of the prosthesis.

• Rigidity is an important characteristic of minor connectors as it aids in

force distribution. So, any bending or deformation will lead to

concentration of forces.

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3. Rests:

Extensions of a partial denture, placed in rest seats, which are prepared on

either the Occlusal, Lingual surfaces or Incisal edges of the teeth, providing

support to the partial denture.

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4. Direct Retainers:

That component of RPD that is used to retain and prevent

dislodgment consisting of a clasp assembly or attachment.

Clasp Assembly: that part of RPD that acts as direct retainer and/

or stabilizer for a prosthesis by partially encompassing or

contacting an abutment tooth.

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5. Indirect Retainer:

A part of RPD which assists the direct retainers in preventing

displacement of distal extension denture base by functioning

through lever action on the opposite side of the fulcrum line.

6. Denture Base:

Defined as that part of a denture which rests on the oral mucosa

and to which teeth are attached.

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A Properly Constructed PD Must Have:

❑Support: Resistance to vertical seating forces (provided by teeth and

mucosa).

❑ Retention: Resistance to vertical displacing forces.

❑ Stability (bracing) resistance to horizontal and lateral displacement.

All the above should be within the physiological limits of the tissue involved

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