Effects of exposure time and exposure distance on the micro-mechanical properties of light cured pit and fissure sealants

DOI: https://doi.org/10.25241/stomaeduj.2019.6(1).art.1


Introduction  The study aimed to perform comparative measurements on the effect of exposure time and exposure distance on the micro-mechanical properties Vickers hardness (HV) and indentation modulus (E) of light cured, resin-based pit and fissure sealants.
Material and Methods Thirteen pit and fissure sealants were selected. Combinations of three clinically relevant exposure times (10, 20, 40 s) and two, fixed sample – light source exposure distances (4 and 7 mm) were tested. The HV and E of each group (n = 6) were measured with an automatic hardness indenter. Data were analyzed by a multi-variant analysis and partial eta-squared (ηp2) statistic.
Results The factor “material” had the most significant influence (significance level α ≤ 0.05) on the measured micro-mechanical properties E and HV as shown by a ηp2 statistic (ηp2 = 0.939 and 0.927 respectively). The factor “exposure time” had a significant but moderate influence on both material properties E and HV (ηp2 = 0.297 and 0.084) whereas a smaller but significant effect of the factor “exposure distance” was only observed for E (ηp2 = 0.049).
Conclusions Properties E and HV are strongly influenced by the type of sealant. On the other hand, the exposure distance had a low influence on these, whilst the exposure time had a greater influence. Exposure time and to a lesser extent exposure distance have a significant effect on the micro-mechanical properties of pit and fissure sealants.
Practical Implications We conclude these findings indicate exposure time to be more significant when considering clinical application of these materials.

Keywords Pit and fissure sealants; micro-mechanical properties; pediatric dentistry; dental materials; curing.


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