17869919
Description
Discuss the problems that may
beassociated with the uni-lateral(Kennedy
Class 2) and bi-lateral(Kennedy Class 1)
free end saddle RPD.How may they be
solved?
- Both Kennedys class 1 and 2 involve free end saddles, problems occur as a result of the dentures inability to
anchor itself down.
- Class 1 must compensate for rotational forces as both saddles
are free to move, they must be designed in consideration of:
- provision of optimum support for the distal extension denture
bases
- incorporation of flexible direct retention
- and provision of indirect retention.
- and provision of indirect retention.
- incorporation of flexible direct retention
- provision of optimum support for the distal extension denture
bases
- As class 2 gains some retention from the opposite side however must
include:
- well-adapted denture base
- properly designed direct retention
- and appropriately positioned indirect retention.
- and appropriately positioned indirect retention.
- properly designed direct retention
- well-adapted denture base
- Problems
- if designed with unequal forces being distributed over the RPD, rapid destruction of the periodontal tissues may
happen with an additional potential of abutment loss.
- Flexible direct retention is designed to flex or move
into an area of greater undercut as forces are
applied to the rpd, clasp design is essential as this
prevents rocking movement in the denture.
- Flexible direct retention is designed to flex or move
into an area of greater undercut as forces are
applied to the rpd, clasp design is essential as this
prevents rocking movement in the denture.
- destruction of the residual ridges will decrease their height, causing rocking to the denture and needing
continuous realignments of the denture
- All portions of the residual ridge that can
provide support should be covered by an
accurately fitting denture base. Broad
coverage permits favourable distribution of
stresses often described as a snowshoe
effect.
- All portions of the residual ridge that can
provide support should be covered by an
accurately fitting denture base. Broad
coverage permits favourable distribution of
stresses often described as a snowshoe
effect.
- With the free end saddles in some instances sticky foods may lift denture bases away from supporting tissues.
This displacement produces rotation of the rpd on the most posterior abutment
- auxiliary rests should be placed as far as is
practical from the fulcrum line, rests minimize
rotation and aid in retention, these are indirect
retainers.
- auxiliary rests should be placed as far as is
practical from the fulcrum line, rests minimize
rotation and aid in retention, these are indirect
retainers.
- if designed with unequal forces being distributed over the RPD, rapid destruction of the periodontal tissues may
happen with an additional potential of abutment loss.
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