EUROPEAN JOURNAL OF PAEDIATRIC DENTISTRY CONTENTS.
Vol. 8 No. 4        December - 2007
ISSN: 1591-996X      UBIC: 116-O

ABSTRACT: Aim of this study was the evaluation of the micro hardness 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 Ywadent ETS, Schaan, Licchtenstein). 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°Cfor 30, 60, 90, 180 and 360 days, and then analysed again with the micro hardness 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 micro hardness values compared to the other tested materials (group I, II, III); surfaces exposed to curing light showed higher micro hardness values than opposite surfaces. Moreover, a significant micro hardness 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 ofO.05.
Conclusion: Because of the good mechanical properties of dental sealants they represent the first chotee materials in pits and fissures sealing.
KEYWORDS: Dental sealants, Compomers, Vickers microhardness, Light-curing.

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