Effects of 445-nm Diode Laser-Assisted Debonding of Metallic Brackets on Shear Bond Strength and Enamel Surface Morphology.

Abstract

Objective: To evaluate the effect of a 445-nm diode laser on the shear bond strength (SBS) of metallic brackets before debonding. Background: Due to the new blue laser technology, very few studies are available in this context. Methods: Seventy metallic brackets (Discovery; Dentaurum, Ispringen, Germany) were bonded to the frontal enamel surfaces of 70 caries-free bovine incisors in a standardized way. Each sample was randomly assigned to the control or laser group, with 35 samples per group. The brackets in the laser group were irradiated with the diode laser (SIROLaser Blue®; Sirona, Bensheim, Germany) on three sides of the bracket bases for 5 s each (lateral-coronal-lateral, a total of 15 s) immediately before debonding. SBS values were evaluated for the control group and laser group. Micrographs of the enamel surface were taken with 10 × magnification to assess the adhesive remnant index (ARI) and the degree of enamel fractures after debonding. Results: There were no statistically significant differences in SBS in the laser group in comparison with the control group (p > 0.05). The distribution of ARI scores was also not statistically significantly different in the laser group in comparison with the control group (p > 0.05). Three enamel fractures occurred in the control group and one in the laser group after debonding. Conclusions: Irradiation of metallic brackets with the 445-nm diode laser before debonding does not significantly reduce the SBS values and does not influence the remaining amount of adhesive on the enamel surface. The risk of enamel fractures during debonding is therefore not clinically affected.