Removable partial dentures

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Removable partial dentures (RPDs) are for partially edentulous dental patients who desire to have replacement teeth for functional or esthetic reasons, and who cannot have fixed partial dentures (crowns and bridges) for any number of reasons, such as lack of distal abutments or because of financial limitations.

Removable partial dentures are named so because patients can remove and fit as and when required, without professional help. Conversely, a fixed prosthesis can be removed only with the help of a dental professional.

Partially edentulous conditions

Depending on where teeth are missing, situations can be grouped under four different classes, as defined by Dr. Edward Kennedy in his classification of partially edentulous arches.

Class I (bilateral free ended partially edentulous)
Class II (unilateral free ended partially edentulous)
Class III (unilateral bounded partially edentulous)
Class IV (bilateral bounded anterior partially edentulous)

Class I to III can have modified status provided bounded space/s are added to the existing class. These modifications were defined by Oliver C Applegate.

Components of an RPD

Rather than lying entirely on the edentulous ridge like complete dentures, removable partial dentures possess clasps of metal or plastic that "clip" onto the remaining teeth, making the RPD more stable and retentive.

The parts of an RPD can be listed as follows (and are exemplified by the picture above):

Connecting structures-
*Major Connector (the thick metal "U" in the RPD above is a lingual bar, a typed of major connector)
*Minor Connector (the small struts protruding from the lingual bar at roughly 90 degree angles)

Retaining structures-
*Direct Retainer (example is in the upper left of upper photo, lower right of lower photo, the clasp arms act to hug the teeth and keep the RPD in place)
*Indirect Retainer (example are the other two minor connectors, which are cingulum rests for the two canines; the one closer to the teeth also has a retentive clasp)

Supporting structures
*Rests (occlusal and cingulum), i.e lying on the back teeth or the front teeth)
Base (the pink material, mimicking gingiva)

Teeth

References

Davis Henderson, Victor L. Steffel. McCRACKEN's Removable partial prosthodontics, 1973. 4th Ed.

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