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Evaluation of Vickers hardness of different types of acrylic denture base resins with and without glass fibre reinforcement.

OBJECTIVE
To evaluate the Vickers hardness of different acrylic resins for denture bases with and without the addition of glass fibres.


BACKGROUND
It has been suggested that different polymerisation methods, as well as the addition of glass fibre (FV) might improve the hardness of acrylic.


MATERIALS AND METHODS
Five types of acrylic resin were tested: Vipi Wave (VW), microwave polymerisation; Vipi Flash (VF), auto-polymerisation; Lucitone (LT), QC20 (QC) and Vipi Cril (VC), conventional heat-polymerisation, all with or without glass fibre reinforcement (GFR) and distributed into 10 groups (n = 12). Specimens were then submitted to Vickers hardness testing with a 25-g load for 30 s. All data were submitted to anova and Tukey's HSD test.


RESULTS
A significant statistical difference was observed with regard to the polymerisation method and the GFR (p < 0.05). Without the GFR, the acrylic resin VC presented the highest hardness values, and VF and LT presented the lowest. In the presence of GFR, VC resin still presented the highest Vickers hardness values, and VF and QC presented the lowest.


CONCLUSIONS
The acrylic resin VC and VW presented higher hardness values than VF and QC resins. Moreover, GFR increased the Vickers hardness of resins VW, VC and LT.