تاثير نمط جبس المثال النهائي في انطباق قواعد الاجهزة الكاملة المتحركة

Background& Objective: Adapting of the complete denture will ensure its retention. Poly(methyl methacrylate) is considered to be the best material to manufacture denture bases. However it incurs changes in dimension and volumetric contraction which affects the adaption of dentures and therefore the retention. The purpose of this study was to compare two types of stone casts in their effect on accuracy of fit of complete denture base. Materials & Methods: The research sample consisted of 60 fully replicate master casts (30 casts were poured in type III stone and the remaining 30 casts were made from type V stone) which were obtained by copying a metal die represented an edentulous maxillary arch. All denture was completely waxed using the same thickness of base plate wax and teeth They were made so by making accurate copy of the teeth. After polymerization in the same working conditions ,the dentures were trimmed. The dentures adaptation was studied by using the method of weighing the elastomeric silicon layer between each denture and the metal die. Data were statistically analyzed by using T test (P≥ 0.05) . Results: The means of elastomeric silicon layers weight in group of stone type V were (0.09±1.26) statistically significant less (P < 0.05 )than those of stone type III group (0.14±1.89) . Conclusions: within the limitation of this study the accuracy of fit of complete denture base was better with high expansion stone (Type V).