Effects of surface coating agents on surface microhardness of bis-acryl provisional materials

Objectives: To compare surface microhardness of bis-acryl provisional materials after applied various type of surface coating agents by using vicker's hardness tester.
Methods: Forty bis-acryl specimens which were finished and polished were randomly divided into 8 groups, with n=5. 1) Protemp^TM4 without surface coating, 2) Protemp^TM4 coated with Palaseal^®, 3) Protemp^TM4 coated with EQUIA Forte^® coat, 4) Protemp^TM4 coated with Optibond^TM FL, 5) LuxaTemp^® without surface coating, 6) LuxaTemp^® coated with Palaseal^®, 7) LuxaTemp^® coated with EQUIA Forte^® coat, 8) LuxaTemp^® coated with Optibond^TM FL. The specimens from each group were tested for surface hardness by Vickers surface hardness tester. Load used was 50 gf. for 15 seconds. The indentations made were evaluated and measured with stereomicroscope at 50x. The measurements were converted into HV (Vicker’s hardness number) and analyzed with two-way ANOVA.
Results: The mean surface hardness values of LuxaTemp^® group were statistically higher than Protemp^TM 4 group. The mean surface hardness values of LuxaTemp^® group were statistically decreased after application of Palaseal^® and Optibond^TM FL. There were no statistically significant difference between the surface hardness values of LuxaTemp^® coated with EQUIA Forte^® coat and LuxaTemp^® control group. However, it was statistically different from the surface hardness of the other groups.
Conclusions: From the limitation of this study, the three coating agents applied on Protemp^TM4 have no effects on its surface microhardness. On the other hand, surface microhardness of coated LuxaTemp^® group showed statistically significant decrease, except for EQUIA Forte^® coating group which remains unchanged.