REMOVABLE PARTIAL DENTURES (RPD)

A removable partial denture (RPD) (Fig. 2) is a removable prosthesis that replaces one of more teeth.  It is most commonly made out of a biocompatible chrome-cobalt alloy that is silver in color.  The missing teeth are replaced with plastic teeth, composite resin teeth or porcelain teeth.  It is often necessary to use pink denture base material to secure the teeth to the metal framework and provide acceptable esthetics for the missing bone and gum.

A RPD is held in place by metal hooks or wires (clasps) (Fig. 1 & 4).  The clasps may show during talking and smiling.  If the display of the clasps is objectionable, precision attachments can be used to make for a more esthetic prosthesis.

Unlike a cemented, fixed bridge that is entirely tooth supported, a RPD is often supported by not only the teeth, but also by the gum and bone in the area of the missing teeth (Fig. 3).

 

Fig. 1     The replacement teeth are supported by natural teeth on either side for better support.  Notice the metal hooks (clasps) that engage the teeth for retention.  The clasps may be visible, and they may collect food debris when eating.	Fig. 2     Removable Partial Denture for the upper jaw.  Note that the denture is supported by a combination of teeth (right side of photo) and gum (left side of photo).	Fig. 3    There is no back tooth on this side to support the denture base.  As a result the support is provided by the gum and bone on this side.  Chewing will not be as effective on this side, because the gum cannot take as much pressure as the teeth.  Periodically the denture base will need to be relined as the gum and bone shrink from under the denture.

ADVANTAGES

1.  A RPD is the least expensive prosthesis for replacing one or more teeth
2.  A RPD can replace not only the missing teeth, but it can provide a prosthetic replacement for the gum
     and the bone that has been lost due to atrophy, trauma or disease.
3.  Compared to a fixed bridge, a RPD can be removed from the mouth for easier and more effective
     hygiene.
4.  If significant bone loss has occurred, a RPD may provide better esthetics than a fixed bridge, because
     the missing teeth, bone and gums can be replaced.
5.  Compared to a complete denture, keeping the teeth for a RPD will help preserve the bone in the
     vicinity of the supporting teeth.  This will provide a better foundation and a more secure prosthesis.
6.  Compared to a complete denture, you can bite and chew harder, because teeth are supporting the 
     prosthesis.
7.  If a tooth or teeth are lost due to decay or gum disease, it may be possible to add the teeth to the
     existing RPD without remaking a new restoration.

 

Fig. 4      Metal clasp on an old partial denture.  Occasionally the metal clasp may need to be adjusted for retention.  After repeated adjustments, the clasp may break due to metal fatigue.	Fig. 5    Old partial denture.  Note how the denture teeth and denture base are stained.  The metal clasps may be visible.  The metal clasps put extra pressure on the teeth which may lead to future tooth loss.	Fig. 6    Old upper denture and lower partial denture.  Due to wear of the teeth and bone loss under the dentures, the back teeth no longer touch.  This makes chewing very inefficient, and puts a lot of extra pressure on the front teeth, because they are the only teeth that can touch for chewing.

DISADVANTAGES

1.  The teeth will need to be reshaped to accommodate a RPD and achieve adequate support and 
     retention.
2.  Occasionally, the gum and/or bone may need to be surgically modified in order to make a RPD that is
     properly extended.
3.  Crowns may be required to provide adequate contours to retain the partial denture.
4.  Metal hooks (clasps) which provide retention for the partial denture (Fig. 4), may be visible and
     unesthetic.
5.  The clasps will go out of adjustment and the partial denture will lose retention.  Periodically the
     clasps will need to be adjusted (Fig. 4). 
6.  The metal clasps may fatigue and break.  Usually the partial denture can be modified or repaired
     after a clasp breaks.
7.  Occasionally, seeds or small hard bits of food may get under the RPD when you are eating.  This can
     be painful when you are chewing, and cause embarrassment when you have to excuse yourself to
     clean your denture.
8.  The clasps tend to collect food during eating.  You can avoid this problem and the unsightly display of 
     metal by having “precision attachments” added to the partial denture to provide retention.  Precision
     attachments have the added advantage of reducing the stress on the teeth to which they are
     attached.
 9.  The partial denture will move during chewing, and food will collect around it.
10. The teeth can still get cavities and gum disease.
11. If a strategic tooth or teeth are lost due to decay, trauma or gum disease it may be necessary to
      make a new partial denture or a complete denture
12. The denture will need to relined due to bone loss (Fig. 6) in areas where there are no teeth.  This is
      typically in 3 to 5 years after the prosthesis is made.
13. The partial denture will need to be replaced in 7 to 10 years, on average.
14. As the bone shrinks, and the fit of the RPD changes, sore spots may develop, and the RPD will need
      to be adjusted.