What is rest in prosthodontics?
Rest : According to GPT 9 A rigid extension of a removable partial denture that contacts the occlusal, incisal, cingulum, or lingual surface of a tooth or restoration, the surface of which is commonly prepared to receive it.
What is the name of tooth rest?
1. Occlusal rests—so named because they are seated on the occlusal surfaces of posterior teeth. 2. Lingual or cingulum rests—those seated on the lingual surfaces of anterior teeth, usually maxillary canines.
What is a occlusal rest in dentistry?
Quick Reference. A rigid, usually metal, extension of a removable partial denture which rests on the occlusal surface of a posterior tooth for the support of a prosthesis.
What is RPA clasp?
T he RPA clasp (rest, proximal plate, Akers clasp)? The design characteristics that allow an RPI clasp’s ‘ to release from an abutment tooth when occlusal forces are applied to the denture base are shown in Figs.
What is auxiliary occlusal rest?
20. AUXILIARY OCCLUSAL REST Most frequently used. Located on the occlusal surface far away from distal extension denture base. It is placed perpendicular to the midpoint of the fulcrum line. Ideal location is central incisor, which is weak, therefore bilateral rests on first premolars are effective.
What are rest seats?
A REST PREPARATION or REST SEAT is any portion of a tooth or restoration properly prepared to receive a rest.
What is auxiliary rest in RPD?
A rest that is responsible for additional support or indirect retention is called an auxiliary rest or secondary rest. 21. Primary rests prevent vertical movement of a prosthesis toward the tissues and also help transmit applied forces to the supporting teeth.
What is rest seat?
When do you use a lingual bar?
The lingual bar should be used for mandibular removable partial dentures when sufficient space exists between the slightly elevated alveolar lingual sulcus and the lingual gingival tissue.
When do you use occlusal rest?
Occlusal rests will be used on mesio-occlusal and disto-occlusal surfaces to support restoration and direct forces over the greatest root mass of the abutment.
What is combination clasp?
A combination clasp is a circumferential retainer for a removable dental prosthesis that has a cast reciprocal arm and a wrought wire retentive clasp (GPT8). It consists of a wrought wire retentive arm and a cast reciprocal arm. The combination of a wrought alloy and cast alloy gives it the name ‘combination clasp’.
What is a cingulum-shaped rest preparation?
The floor of the cingulum-shaped rest preparation is placed in the bulk of the cingulum. The floor of the rest preparation is deepest toward the center of the tooth thus forming a positive faciolingual seat. The preparation extends more cervically on the mesial and distal thus forming a positive mesiodistal seat.
What is a crescent shaped cingulum?
Crescent shaped cingulum rests Commonly used on maxillary cuspids and centrals Often can be carved into existing virgin maxillary central incisor or canine 16.
Which cingulum rest for mandibular teeth?
Crescent shaped cingulum rests Difficult to use on mandibular teeth without preparing a three quarter or full veneer crown as is seen in this patient *The incisal rest is more commonly used in mandibular anterior teeth 17.
What is the shape of a lingual rest seat?
The form of a lingual rest seat should be V shaped when viewed in cross section.from the lingual aspect the outline form should be crescent shaped.this geometry provides some freedom of movement in MD direstion hence functions as a ball and socket joint.