بررسی تأثیر چند روش پلیمریزاسیون بر تغییرات ابعادی آکریل سرماسخت ایرانی (آکروپارس)

Statement of Problem:Iranian product, Acropars autopolymerizing acrylic resin is nowadays widely used in dental prostheses. Dimensional change is a common problem among Iranian made acrylic resins in making custom trays and record bases, seems to be more than the similar foreign products. In order to achieve a technique for making a record base with minimum dimensional changes, more research is necessary.Purpose: The aim of the present study was to determine a curing technique for Iranian autopolymerizing acrylic resins leading to the least polymerization shrinkage and the most adaptation between record bases and stone casts.Materials and Methods: In this experimental study, 40 stone casts were divided into four 10- member group. For each group, polymerization shrinkage was determined at three points with one of the following techniques: Bench curing, Curing under a coat of petroleum jelly , Curing in a monomer saturated atmosphere, Curing in boiled water. Adaptation between bases and stone casts were measured at three points (the right and left crests of the ridge and the midpalatal region) with a light-measuring microscope. To analyzethe data, Variance analysis was used.Results: The monomer atmosphere technique showed the minimum dimensional changes and the samples in boiled water group had the maximum dimensional changes. No statistical differences were observed between other groups.Conclusion: More adaptation between record bases and stone casts was observed in monomer atmosphere polymerization technique. The differences between bench curing and curing under a coat of petroleum jelly techniques with this method were not statistically significant. Therefore, it is suggested for making base records with maximum adaptation.