ABSTRACT. Aim Aim of this study was the evaluation of the microhardness of 4 dental sealants polymerised with
two different curing units. Methods Twenty samples (5x5x2 mm) were prepared with 4 different sealants; 10
samples for each group were polymerised with a plasma curing unit (Apollo 95 E DMD) and 10 with a halogen
curing light (Heliolux DLX Vivadent ETS, Schaan, Liechtenstein). For each section 6 Vickers microhardness
measurements were performed (VMHT 30A, Leica Wien, Austria), 3 on the surface exposed to the light and 3 on
the opposite surface. After the baseline assessment all samples were stored in artificial saliva at 37°C for 30, 60,
90, 180 and 360 days, and then analysed again with the microhardness indenter and observed under
steromicroscope 10X (Leica DM2500 Wien, Austria). Data were then statistically analysed. Results The hybrid
composite Tetric flow (group IV) showed the higher microhardness values compared to the other tested materials
(group I, II, III); surfaces exposed to curing light showed higher microhardness values than opposite surfaces.
Moreover, a significant microhardness reduction was observed after 30 days; values remained unmodified after
60, 90, 180 and 360 days. Statistics Data were then statistically analysed with Anova test for repeated measures,
with a global significance level of 0.05. Conclusion Because of the good mechanical properties of dental sealants
they represent the first choice materials in pits and fissures sealing.
