17861333
Description
Mind Map by Alice Dolman, updated more than 1 year ago
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Created by Alice Dolman
over 5 years ago
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Define “Indirect retention”.
Describethe various components
which can beused to provide it.
- Indirect retention is a method which attempts to reduce the continual loading and unloading of tissues by
preventing movement of the denture base away from the mucosal tissues. It uses an anteriorly placed
component (on the hard or soft tissues) to prevent rotation occurring around a supporting unit (occlusal rest,
onlay).
- Occlusal rests, onlays and continuous clasps, may act as indirect retainers. To carry out these functions they
must be strong, rigid and fit tooth surfaces accurately.
- Occlusal rests, onlays and continuous clasps, may act as indirect retainers. To carry out these functions they
must be strong, rigid and fit tooth surfaces accurately.
- Occlusal rest
- a rigid extension of a removable partial denture onto the
occlusal surface of a posterior tooth for support of the
prosthesis.
- a rigid extension of a removable partial denture onto the
occlusal surface of a posterior tooth for support of the
prosthesis.
- Onlay
- an occlusal rest portion of a removable partial denture that
is extended to cover the entire occlusal surface of the tooth
- an occlusal rest portion of a removable partial denture that
is extended to cover the entire occlusal surface of the tooth
- Continuous clasps
- Circumferential clasp of a removable partial denture in which the body is attached to an occlusal rest and the
clasp arms extend across the buccal or lingual surfaces of more than one tooth before engaging a proximal
surface undercut.
- Circumferential clasp of a removable partial denture in which the body is attached to an occlusal rest and the
clasp arms extend across the buccal or lingual surfaces of more than one tooth before engaging a proximal
surface undercut.
- Principles to be considered when considering incorporating supports in partial denture design.
- 1. The vertical load should be distributed over as many
teeth as possible. One natural tooth to one artificial tooth.
Hence as a saddle length increases, so should the number
of supporting teeth.
- 2.Wherever possible, anterior and posterior
bounded saddles should be supported.
- 3.Support is most effective when movement of the
load-bearing tooth is prevented due to the presence of
adjacent teeth.
- 4. On an isolated standing tooth, support should be spread over both sides
to prevent rotation.
- 5. When designing a partial denture for free end saddles (Kennedy classes 1 & 2): By moving
the support anteriorly, the load taken by the supporting tooth may be decreased, causing
the load on the ridge to increase.
- 6. Support should not interfere with occlusion or articulation. Any imbalance of the
occlusal table can cause TMJ problems.
- 1. The vertical load should be distributed over as many
teeth as possible. One natural tooth to one artificial tooth.
Hence as a saddle length increases, so should the number
of supporting teeth.
- Materials
- 1) Yellow or white casting golds.
- 2) Cobalt Chromium casting alloys. (Rests made from this may be thinner
than (1) above.)
- 3) Wrought stainless steel. (These are used only
temporarily since they cannot be adapted to fit
tooth surfaces accurately.)
- 1) Yellow or white casting golds.
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