Method: Forty bovine incisors were sectioned into two halves to obtain experimental and control specimens. The teeth were randomly divided into four groups and the experimental specimens were treated with one of the following bleaching treatments for four weeks: 10% carbamide peroxide (Opalescence, Ultradent Products), 10% hydrogen peroxide (Opalescence Treswhite Supreme, Ultradent Products), 3% carbamide peroxide plus lactoperoxidase (WhiteKin, Kin) or 3% carbamide peroxide plus 2.7% carbamide peroxide (Clysiden Kit Express, Ern).
Microroughness of enamel surface of twenty teeth was measured in “average roughness” (Ra), “root mean square roughness” (Rq) and “total roughness” (Rt) by confocal microscopy in reflection mode. Another twenty teeth were selected to determine chemical and morphological changes in enamel surfaces using energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM). Results were analyzed by Student´s t test for paired samples (p<0.05).
Result: Significantly higher microroughness of bleached enamel was detected according to Ra, Rq and Rt values for Clysiden group and Ra values for Whitekin. There was no statistically significant difference in surface roughness for Treswhite or Opalescence specimens. EDS results showed no significant changes in Ca, P and O content in any group.
Conclusion: Clysiden and Whitekin OTC bleaching products may affect enamel microroughness, although this effect was not related to a decrease in Ca, P and O content.