AN EXPERIMENTAL INVESTIGATION IN DESIGN AND FORCE DISTRIBUTION WITH UNILATERAL MANDIBULAR DISTAL EXTENSION REMOVABLE PARTIAL DENTURES

For the purpose of analyzing the effect of removable partial denture design on lateral force distribution, this investigation was accomplished by determining the amount of the excursion of the abutment teeth resulting from the application of lateral force while a partial denture is placed on a simulated model which was constructed of methyl methacrylate and Silicone rubber. Special devices for measuring tooth mobility were used. These data were compared with the results from intra-oral experiments that had been reported by the present authors. Its results were as follows: (i) Lateral force directly applied against the abutment teeth was markedly reduced by wearing of the removable partial dentures. (ii) The abutment tooth nearest the denture saddle generally received the highest value of the force distribution. (iii)The bilateral denture design was highly effective for increasing the resistance against lateral force. (iv) The T-type clasp bas soft bracing action against lateral force distributions