Partial Dentures

Definition:

A partial denture is a removable dental prosthesis that replaces one or more, but not all, missing teeth in an arch and is supported by the remaining natural teeth and/or the oral tissues.

Principles of successful removable partial dentures:

Successful RPDs must satisfy biomechanical, biological, and aesthetic principles. To achieve this the 6 principles must be satisfied:

1. Support → Resistance of movement of the denture towards the tissues

   • Provided by rests on abutment teeth and denture based coverage (mucosal support)

2. Retention → Resistance to dislodge along the path of insertion

   • Achieved in 3 ways:

     1. Direct retention (clasps engaging undercuts)

     2. Indirect retention (prevents rotation around a fulcrum line)

     3. Frictional retention from guide planes

3. Stability → Resistance to horizontal or rotational forces

4. Hygienic

   • Easy to clean

   • Hygienic within the mouth (e.g. not trap food)

5. Aesthetic

   • Support facial tissues

   • Look good to the patient

6. Simplicity (in design)

Materials RPDs are made from:

• Acrylic resin

  • Advantages: good aesthetic, easy to repair/adjust, cheap, does not corrode, easy to adapt for the technician

  • Disadvantages: low resistance to fatigue, can't construct clasps/rest with it for RPDs, poor impact resistance

• Cobalt-chromium alloys

  • Advantages: Strong in thin sections, doesn't corrode, hard and rigid

  • Disadvantages: more expensive than acrylic, more difficult to achieve a good fit, more difficult to repair/modify, more clinical stages

• Stainless steel

  • Mainly used for wire clasps

• Gold alloys

  • Advantages: biocompatibility and workability

  • Disadvantage: cost

• Titanium

  • Advantages: biocompatibility, lightweight, corrosion-resistant

  • Disadvantages:

Denture design:

Beckett classification: (insert picture of this?)

Used to evaluate the arch and the edentulous areas on how it will receive support from an RPD.

1. Tooth supported

   • The denture base is fully supported by abutment teeth (e.g. bounded saddles)

2. Mucosa supported

   • The denture base is supported entirely by soft tissues (e.g., free-end saddles).

3. Tooth and mucosa supported

   • Support from both soft tissues and abutment dentition