Retentive Arm Design Factors
Posted on 11/25/2011
Among the elements of the clasp assembly, the retentive arm offers the most varied design options. These options include the I-bar, T-bar, Y-bar, circumferential clasp and numerous others. These retentive arm designs will be discussed in more detail in future blog posts. However, I would like to take a moment to outline the factors that influence which retainer should be chosen.
The factors that influence the design of the retentive arm include:
1. The location of the undercut
2. Ability to provide adequate reciprocation
3. Minimize disruption to normal tooth and tissue contours
4. Achieve aesthetic requirements of the patient
It should be noted that all clasp assemblies should be designed to touch the abutment tooth surface at three distinct points - essentially providing for more than 180 degree encirclement of the abutment tooth. These three points of contact are created through all of the various elements of the clasp assembly, and also influence the retentive arm design chosen.
*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.
The factors that influence the design of the retentive arm include:
1. The location of the undercut
2. Ability to provide adequate reciprocation
3. Minimize disruption to normal tooth and tissue contours
4. Achieve aesthetic requirements of the patient
It should be noted that all clasp assemblies should be designed to touch the abutment tooth surface at three distinct points - essentially providing for more than 180 degree encirclement of the abutment tooth. These three points of contact are created through all of the various elements of the clasp assembly, and also influence the retentive arm design chosen.
*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.
