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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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