Evaluation of etched enamel using quantitative light-induced fluorescence

Abstract

The purpose of this study is to evaluate the effect of etching on the ground and unground enamel using quantitative light-induced fluorescence (QLF). Thirty extracted incisors were used in the study. One-half of the labial surface of each tooth was ground with #400- grit SiC paper. The other half was left intact. Ground and intact surfaces were coated with nail varnish leaving rectangular windows of enamel uncoated. A 32% phosphoric acid gel was applied for 15, 30, 60 seconds. The mineral loss in terms of percentage of fluorescence (delta F) was assessed by QLF at baseline and after etching. Effect of etching time and mechanical pretreatment were analyzed with independent t-test and one-way ANOVA. Grinding the enamel before etching for 15 seconds and 30 seconds had a significant effect on demineralization. However, no significant difference in demineralization was observed between the ground and unground enamel with 60 seconds of etching. The ΔF values decreased with increased etching time. But there was no significant difference in the ΔF values between 15 seconds and 30 seconds, and 30 seconds and 60 seconds in both ground and unground enamel. Demineralization after acidetching can be quantified using QLF. The result indicated that the degree of demineralization increases with etching time and mechanical pretreatment.