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Comparison of Linear Dimensional Changes of two Heat- cure Acrylic Resins

Sta tement of problem: Although ac rylic resin mater ials have grea t features for mak ing arti ficia l dentures, but still dimensional change is a common prob lem in processing them. Purpose: The a im of this study was to compare the linear dimensiona l changes of two heat-cur e acry lic resi ns. Materials and Method: In th is desc riptive study, twenty specimens in two gro ups were made by "Acropa rs" and "Meliode nt" acry lic resins according to the man ufac turerʹs recom menda tions in a metalli c mo ld. Dime ns ional change s were measured at one , th irty and sixty weeks afte r processing with a digital ca liper. The resuIts were ana lyzed using T-test, T- pa ired test and repeated meas ure ANOYA. Results : Conside ring the dimens ional changes, there was a difference in the firs t day eq ual to 0.42 ± 0.28 mm, in day thirty : -0.09±0.42 mm, and in day sixty : 0.07±0.22mm be twee n the two ac rylic res ins, showing no sta tistica lly significant differences ( p =0 .21). Howe ver, there were significant differences betwee n d ifferent times of measurement s ( p =0.00 I). Conclusion : "Me liodentʹ acrylic resir, had more dimensional stab ility when compared to "A cropars" resin but there was not any s ignifica nt diffe rence betwee n the two acrylic resin s in the day sixty. There were sign ificant differences between different times of measurement s; the maximum difference between these two types of acry lic resins was in first day after polymer ization