The effect of acid etching times on ground primary enamel.

The purpose of this study was to investigate the relationship of etching times on the effect of acid etching on the ground primary enamel with respect to the quality of etching patterns. Labial surfaces of 40 extracted or exfoliated caries-free primary anterior teeth were used. The outer, middle and inner enamel layers were ground without water cooling with a carbide bur from the distal to the mesial direction on the same labial surfaces of the enamel. Each layer was divided into incisal, central and cervical areas. Forth percent phospholic acid gel was used for each etching time group, 10, 20, 30 and 60 seconds. All specimens were washed with an air spray for 30 seconds. The following observations were obtained using the SEM: 1. Over-etching was evident in all cases etched for 60 seconds and this characteristic was particularly prominent in the inner enamel layers. 2. Thirty seconds was the optimal time for etching on the ground primary enamel.