Diferentes Protocolos de Grabado Ácido en Dentina; Estudio Micromorfológico.

Abstract

Evaluate in endodontically treated teeth the effects of different etching protocols on dentinal tubule exposure and diameter at three dentin zones. Sixty healthy firstpremolars from human volunteers were studied. Each tooth received endodontictreatment. Teeth were transversely sectioned 5 mm below amelocemental junction andlongitudinaly sectioned in the buccolingual direction, obtaining two crown halves. Eachcrown half was grouped according to etching protocol into: Control, EDTA, H3PO4 15 and 45 sec., e H3PO4 15 and 45 seg. + NaOCl. Three dentinal areas were analyzed withscanning electron microscope (SEM) within each tooth: coronal dentin, pulp chamber dentin and the beginning of the root canal. Comparison between dentin zones for each treatment was made with Student’s t-test for paired data, using P<0.05 for statisticalsignificance. No significant differences in dentinal tubule exposure within the threestudied zones were found. However, when comparing tubule diameter, higher valueswere obtained at the three dentin zones studied when H3PO4 and NaOCl wer usedin combination. The results of this study showed heterogeneous behavior of differentdentin zones after exposing them to various total etch protocols. The use of 37% H3PO4 for 15s did not ensure a uniform etch in the three studied zones. Protocols withH3PO4 for 45s with 5%NaOCl for 1 min, incorporated as a deproteinizing agent, couldallow more predictable and appropriate etching patterns in endodontically treated teeth.