Molhabilidade da dentina erodida sob ação de dentifrícios dessensibilizantes

Abstract

Desensitizing dentifrices that occlude dentinal tubules act by mineral deposition on the surface and inside dentinal tubules, which may cause may cause changes in the adhesion properties of the dental surface, such as the substrate wettability by adhesive systems. The aim of this study was to evaluate the effect of desensitizing dentifrices on the wettability and topographic analysis of eroded dentin. Eighty fragments of bovine dentin (7mmX7mm) were planned, polished and immersed in 10mL of 0,3% citric acid (pH=3,2) during 2 hours. The specimens were randomly divided in eight groups according to the desensitizing agent: sodium fluoridecontrol (C); 8% arginine and calcium carbonate (DA1); sodium calcium phosphosilicate (DA2); and strontium acetate (DA3) and brushing time simulation (7 and 21 days). The specimens were submitted to mechanic brushing cycles of 3 and 9 minutes, equivalents to 7 and 21 days of brushing, three times a day, with a soft brush. Dentin etch with 37% phosphoric acid for 15 seconds and then washed for 30 seconds. A drop of 10µL adhesive system Single Bond Universal (3M ESPE) were placed on each specimen surface and the contact angle between dentin surface and adhesive system were measured using a Goniometer. Twelve other specimens (n=3) were brushed under the same experimental conditions for 21 days and the dentin topography was observed with Confocal Laser Scanning Microscope, before and after etch of the brushed dentin surfaces. Data were summited to 2-way ANOVA analysis and the results presented that the time factor had a statistically significant effect (p <0.05) on the wettability variable, while the treatment factor alone and the interaction between treatment and time factors, had no statistically significant effect on the variable study (p ≥ 0.05). Therefore, the use of desensitizing dentifrices did not interfere with the wettability of etched dentin after 7 and 21 days of brushing. Brushing time factor, alone, determined reduction of wettability after 21 days.