بررسي ميزان انقباض خطي ناشي از پلي مر يزاسيون در رزينهاي آكريلي مورد استفاده درساخت رستوريشنهاي موقتي ثابت

Evaluation of linear polymerization shrinkage of fixed provisional acrylic resins

Background & Autopolymerized acrylic resins are one of the most important materials which are used for construction of fixed provisional restorations. Since the linear polymerization shrinkage affects the desired properties of such restorations, the amount of this type of shrinkage in three types of acrylic resins (Tempron, Duralay & Acropars) is evaluated in this research. Methods & Materials: This research is an experimental study. I 1 sample of each types of above acrylic resins were made by a stainless steel mold (in disk form). The samples were measured by Profile Projector system from their two specific diameters. The measurements were compared with initial dimensions of mold as reference point. Results: Finally it is clear that Tempron resin has less polymerization shrinkage (0.0758%) and Duralay resin has high shrinkage ( 0.3333 % ). Conclusion: Dimensional change of Duralay samples was significant from initial diameter of mold (P<0.05). Dimensional change of Tempron acrylic resin samples was not significant. Acropars resin has no predictable result in this situation because more than half of its samples have increased diameter.