Krisztina Marton

Removable Partial Dentures

Every denture: acrylic denture with wire clasp (spoon denture)

Designing Removable Partial Dentures

The Individual Parts of the RPD

1. Saddles

2. Occlusal rests and similar components

3. Direct retainers

4. Connectors

Saddles Replaces the lost alveolar tissues (flange) and carries

arteficial teeth (real saddle)

Types:

Bounded

Free end

Material of the fitting surface

Acrylic resin Disadvantageous to the health of the underlaying mucosa and

the gingival margin of the remaining teeth

Metal, or metal-acrylic combination Provides better health of the mucosa because of the metal’s

highly polished surface, acrylic can provide acceptable esthetics

Connectors of the RPD

Upper arch

Distributes load to the mucosa Butterfly

Horseshoe

Fenestrated

Sceletonized

Labial bar

Minor connectorsconnect small of the metal frame to the baseplate

Major connectorsconnect the two sides of the denture to eachother

• Lower arch– Not distributes load to the

mucosa• Lingual plate• ”finger type” lingual plate• Lingual bar• Lingual bar with continuous

clasp (Kennedy bar)• Sublingual bar• Dental plate• Labial (or buccal) bar

Lingual bar

Lower connectors

Lower connectors 2

Direct retainers of the RPD These provide resistance to movement of the denture

along the path of displacement and/or path of insertion and withdrawal during any function (hindering its removal of its supporting tissues

Types CLASPS

Retentive clasp arms (usually incorporated in clasp units)

PRECISION ATTACHEMENTS

Clasps As the denture is inserted, the flexible tip of the

retentive arm passes over the maximum bulbosity (the prosthetic equator) of a tooth and enters an undercut area.

Once the denture is fully seated, the clasp sits passively in its place , just contacting the tooth surface without forcing on it.

As the denture is subjected to displacing forces during function , the tip of the clasparm is drawn back towards the maximum bulbosity of the tooth . If the displacing forces do not exceed the level of lifting the clasp arm over the survey line the denture will stay in position

Clasp Types:

gingivally aproaching

occlusally aproachingMaterial:

Rigid: Cast metal (usually cast together with the baseplate) Gold alloys

Silver palladium alloys

Cobalt cromium alloys

Stainless steel

Titanium

Elastic: Wrought wire (later adapted to the flange) Gold

Stainless steel

clasparm

Clasp unit

Gingivally aproaching clasp

Occlusally aproaching clasp

Clasp unit