Efeitos de agentes clareadores externos nos tecidos dentários e na junção amelocementária

Abstract

Evaluate with a scanning electron microscope the alterations occurring in enamel, cementum and cementoenamel junction after the use of different external bleaching agents. Fifteen healthy pre-molars were sectioned in the middle with the aid of a cutting machine (Labcut 1010), in the longitudinal direction along the axis of the teeth, obtaining mesial and distal surfaces of each tooth. The mesial surfaces were divided into three groups in accord with the material used (AI- carbamide peroxide 10% - Whiteness Standard 10 FGM®, AII - carbamide peroxide 16% Whiteness Standard 16 FGM®, e AIII - hydrogen peroxide 35% Whiteness HP Maxx FGM®), according to the instructions of the manufacturers. The distal surfaces of each tooth were maintained in artificial saliva, in a bacteriological sterilizer at 37ºC. After whitening the specimens were dehydrated in increasing solutions of acetone and metalized for evaluation using the scanning electron microscope. The results were submitted to statistical evaluation using the Kruskall-Wallis and Mann-Whitey tests. Statistically significant differences were observed between the whitened and unwhitened specimens (p<0.001). In enamel, insignificant alterations were observed, there being no differences between the groups. Loss of structure, with formation of gaps and dental exposure were observed in the cementoenamel junction of the three whitened groups. Being more accented in group A3. It can be concluded that tooth whitening should be done with caution by the dental surgeon, principally in patients who possess gingival recession.