維持歯と維持装置の連結強度 第２報 改良技法による連結強度の向上について

Abstract

In the first report of this study, we were able to point out the key to diminish the denture dynamics in the free-end saddle R. P. D.'s. That is the connecting rigidity between the abutment teeth and the retainers used. The more rigidly the retainers were connected to the abutments, the less the movements of the retainers were obtained. It was revealed that the main factor to diminish the movement of the retainer had derived from the multi-parallel guiding surface/guiding plate functions. It was advocated that the R. P. P. I.(Rest, bi-Proximal, Plate, Ibar) retainers had special function in reducing the denture mobility with their supreme connecting rigidity in contrast to any other clasp retainers.In this present study, we tried to enhance the connecting rigidity of the R. P. P. I. retainers to the level of the Cone-Crown telescopes. Good results to the connecting rigidity was obtained by the two improved methods:1. The precise refractory cast impression material with silicone rubber (Combisil) was effective to the well fitting parallelism of the guiding plates.2. The cast-on, double casting method using a special material to give the separating film by oxidation was also effective in case of the noble metals.