Effect of Er: YAG laser etching on shear bond strength of orthodontic bracket

OBJECTIVES: To evaluate and compare the shear bond strength (SBS) of Erbium laser etched enamel to acid etched and to detect morphological changes on laser etched enamel surface using scanning electron microscope (SEM). Moreover, Laser induced caries resistance is advantageous in Orthodontics. METHODS: This is an Ex vivo study between January 2016 and December 2017, which comprises a total of 50 human premolars, extracted for orthodontic purpose, were used in this study. The samples were randomly divided into 2 groups of 25 each. The first group was etched using 37% phosphoric for 30 seconds. As for the second group, enamel was treated by Er: YAG laser operating at wavelength 2.94µm, power 1.5W and repetition rate 15Hz. Five teeth from each group were selected for SEM evaluation and the study were continued on 20 teeth from each group. Teeth were subjected to shear bond strength test. RESULTS: It showed, no-significant difference between the mean of shear bond strength and of the etched groups (p=0.016). CONCLUSION: It was concluded that, laser etched group (1.5W/15Hz) resulted in clinically accepted bond strength and could be an alternative to conventional acid etching.