Análise da penetração da água em lesões cariosas naturais de esmalte em relação à trajetória dos prismas

Abstract

The direction of transport of liquids in enamel caries lesions (ECL) influences the penetration distance of resin infiltrants and the path of remineralizing agents. It is assumed in the literature that the transport perpendicular to the prisms is negligible, however there are no studies on the proportion of transport parallel and perpendicular to the enamel prisms. The aim of this work was to test the null hypothesis that the proportion of the area of ECL that undergoes water penetration perpendicular to the prisms is negligible. The sample size was of 20 inactive natural ECLs (ICDAS 2 score). Histological ground sections sections (0. 1 mm thick; mean ECL depth of 690 mm ± 247 mm) were dehydrated (48 h at 25° C and 50% of relative humidity) and submitted to the infiltration of distilled water for 2 h at 25° C. A polarized light microscopy technique independent of the orientation of the sample, with temporal resolution of 5 s, was used to map in real time the penetration of water in relation to the prism paths. Two areas of water infiltration direction, parallel-only and perpendicular directions relative to the prisms, were measured with an image analysis software. The mean proportion of penetration area with perpendicular direction was 44.37% (± 20.9%) and the null hypothesis was rejected (p = 0.00003, one-tailed T test, high effect size of 1.15, 95% CI of 0.58-1.75, and power > 80%). We conclude that during penetration of water by capillarity in dry natural ECL, the proportion of area with penetration perpendicular to the prisms is considerably high.