Removable Partial Dentures Krisztina Marton

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 Lower arch Upper arch Minor connectors connect small of the metal frame to the baseplate Major connectors connect the two sides of the denture to eachother Upper arch Distributes load to the mucosa Butterfly Horseshoe Fenestrated Sceletonized Labial bar 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 Material: Types: gingivally aproaching occlusally aproaching 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

Clasp unit clasparm

Gingivally aproaching clasp

Occlusally aproaching clasp

Clasp unit