Removable partial denture design for a few remaining natural teeth

Abstract

T h i s article presents a partial denture design utilizing the hinge-lock apparatus. The patient for whom this design was used is classified as a Kennedy Class II, mod. 1.1 The mandibular arch is bilaterally edentulous, and only four unilaterally posterior teeth are remaining (Fig. 1). The hinge-lock design was used to reduce torque and tooth movement and to provide maximum retention, support, and bracing. 2 In light of these goals it must be remembered that the axis of rotation, i.e., the line around which the denture tends to rotate (Fig. 1), is not bilateral; it is a unilateral line. This presents a problem in providing indirect retention. The ideal location for providing indirect retention is on the side opposite the free-end extension a as far from the axis of rotation as possible. As seen in Fig. 1, the location for indirect retention in this instance lies on the buccal portion of the natural teeth. With the hinge-lock design presented, it is possible to obtain the needed retention through the buccal arms of the hinge-lock apparatus (Fig. 2). The length and location of the buccai arms are important factors in determining the magnitude of stress on the abutment teeth.