Effects of ND: YAG laser radiation on non-diseased human dentin: A scanning electron microscopic study

Abstract

A scanning electron microscopy study was conducted to evaluate the effects of Nd:YAG laser radiation on non-diseased dentin in comparison with citric acid and tetracycline hydrochloride root conditioning. Twenty seven 5 rom x 5 mm dentin segments were obtained from impacted third molars. Each specimen was divided into two equal parts, one half of the specimen was treated by laser radiation (Exp A) and other half of the specimen was equally treated by saline, saturated citric acid or tetracycline hydrochloride ( Exp B ). Three specimens were randomly assigned to each of 6 different treatment groups. Groups 1,2, & 3 ( Bxp A) respectively treated with 1.0 W, 1.25 W, 1.5 W of energy. Groups 4,5, & 6 ( Exp B ) were not irradiated, but treated for 3 minutes respectively with saline, citric acid and tetracycline hydrochloride. The specimens were then fixed and examined by SEM. Specimens treated by laser featured changes not observed in controls (group 4). Those specimens treated by acids exhibited area of exposed dentinal tubules. The results of this in vitro study suggested that laser use during root preparation, at low energy, will remove the smear layer, reduce the size of the dentinal tubules and cause minor alterations to the root dentin.