Cingulum Rest Seats
Posted on 04/09/2012
Cingulum rest seats are most commonly created on canines. Compared to incisal rests, cingulum rests offer a number of advantages including:
1. Superior esthetics
2. Loading is placed at a more apical level, causing less stress on the abutment than an incisal rest
3. Less annoyance to the tongue compared to incisal rests
The technical specifications for cingulum rests include:
1. Usage of a small, round carbide bur or diamond stone and a tapered round-ended or flame-shaped diamond stone.
2. Preparation 1.0 to 1.5mm deep over the center of the cingulum
3. Maxillary rest seats often need to be larger and deeper than mandibular rest seats due to occlusal interferences. The rest must lie within the rest preparation while maintaining sufficient mass for strength.
4. In the event that the enamel is penetrated during preparation, it is advisable to restore the enamel with composite or amalgam before placing the framework.
Please see the photos below for illustrations.
*Portions of this post were adapted from the book: Atlas of Removable Partial denture Design by Dr. Russell J. Stratton and Dr. Frank J. Wiebelt published by Quintessence Publishing Co., Inc. in 1988.
1. Superior esthetics
2. Loading is placed at a more apical level, causing less stress on the abutment than an incisal rest
3. Less annoyance to the tongue compared to incisal rests
The technical specifications for cingulum rests include:
1. Usage of a small, round carbide bur or diamond stone and a tapered round-ended or flame-shaped diamond stone.
2. Preparation 1.0 to 1.5mm deep over the center of the cingulum
3. Maxillary rest seats often need to be larger and deeper than mandibular rest seats due to occlusal interferences. The rest must lie within the rest preparation while maintaining sufficient mass for strength.
4. In the event that the enamel is penetrated during preparation, it is advisable to restore the enamel with composite or amalgam before placing the framework.
Please see the photos below for illustrations.
*Portions of this post were adapted from the book: Atlas of Removable Partial denture Design by Dr. Russell J. Stratton and Dr. Frank J. Wiebelt published by Quintessence Publishing Co., Inc. in 1988.
