Assessment of surface hardness of acrylic resins submitted to accelerated artificial aging.
OBJECTIVE
The aim of this study was to assess the influence of accelerated artificial aging (AAA) on the surface hardness of acrylic resins.


METHODS
The following three commercial brands of acrylic resins were tested: Vipi Flash (autopolymerized resin), Vipi Wave (microwave heat-polymerized resin) and Vipi Cril (conventional heat-polymerized resin). To perform the tests, 21 test specimens (65x10x3 mm) were made, 7 for each resin. Three surface hardness readings were performed for each test specimen, before and after AAA, and the means were submitted to the following tests: Kolmogorov-Smirnov (P>0.05), Levene Statistic, Two-way ANOVA, Tukey Post Hoc (P<0.05) with the SPSS Statistical Software 17.0.


RESULTS
The analysis of the factors showed significant differences in the hardness values (P<0.05). Before aging, the autopolymerized acrylic resin Vipi Flash showed lower hardness values when compared with the heat-polymerized resin Vipi Cril (P=0.001). After aging, the 3 materials showed similar performance when compared among them. The Vipi Cril was the only one affected by AAA and showed lower hardness values after this procedure (Pp=0.003).


CONCLUSIONS
It may be concluded that accelerated artificial aging influenced surface hardness of heat-polymerized acrylic resin Vipi Cril.
School of Dentistry, Ribeirão Preto, São Paulo, Brazil.
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Agnelli
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Mazzetto
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Dos Reis
D000180:Acrylic Resins; D006245:Hardness Tests; D008422:Materials Testing; D013499:Surface Properties; D013997:Time Factors
D000180:Acrylic Resins