A study of partial denture design and masticatory pressures in a mandibular bilateral distal extension case

Abstract

T HE PHYSIOLOGY 0~ MASTICATION encompasses the entire masticatory system. A derangement of any one of its component parts could result in masticatory insufficiency. Occlusion that is defective or inadequate is compensated for by either changes in dietary or masticatory habits. Dietary changes may be such as to produce nutritional deficiencies and also deprive the individual the pleasures of “good eating.” Masticatory habits may be changed because of pain, fear of pain, ineffectual mastication, or lack of occlusion. 1 Food that is insufficiently masticated and swallowed will burden the gastrointestinal system which could lead to, or aggravate existing, systemic disorders. The loss of all posterior mandibular molars presents a serious prosthodontic problem. Adequate replacement requires the restoration of masticatory efficiency and the preservation of the remaining teeth and associated structures. The patient is a “dental cripple,” and the partial denture prosthesis is his “dental crutch.” The effectiveness and usefulness of the partial denture will depend upon its design. It is the design of the partial denture that will evoke favorable or unfavorable biologic responses of the supporting structures to masticatory and nonmasticatory pressures. In a previous partial denture study,2 the effect of partial denture design upon force distribution and masticatory performance was studied on a mandibular unilateral distal extension denture. Mastication was accomplished primarily on the tooth-borne side because of masticatory habit and comfort. The objective in this undertaking is to study, by electronic means, the effect of partial denture design on functional force distribution in a mandibular bilateral distal extension denture as it is related to the supporting tissues. In addition, a study will be made to determine what effect the variations of partial denture designs has on masticatory performance. The influence of the size of the occlusal table on force distribution and masticatory performance will also he studied.