Effect of Nd:YAG and 980nm Diode laser irradiation as a hypersensitivity treatment on shear bond strength of metal orthodontic brackets to enamel

Lasers are one of the tooth hypersensitivity treatments. This study aimed to determine the effect of irradiation of Nd:YAG 1064nm and 980nm Diode lasers, used for hypersensitivity treatment, on the shear bond strength (SBS) of metal orthodontic brackets to enamel. Ethylenediaminetetraacetic acid (EDTA) was used to simulate sensitivity in 70 extracted human premolars. The teeth were radiated with 1w Nd:YAG, 1.5w Nd:YAG, 1w Diode, or 1.5w Diode. All samples were incubated at 37° for 24 hours, after bonding the metal brackets. SBS values and adhesive remnant index (ARI) for each tooth was recorded. One-way analysis of variance (ANOVA) and Kruskal-Wallis test were used to compare the mean SBS and the distribution of ARI scores between the study groups, respectively. The SBS mean from the highest to the lowest were in 1w Diode (25.71Mpa), 1w Nd:YAG (24.66Mpa), 1.5w Diode (23.08Mpa), control (21.68Mpa) and 1.5w Nd:YAG (21.53Mpa) groups. No statistically significant difference existed between different groups, in terms of SBS (p=0.211) and ARI distribution (p=0.066). The application of Nd:YAG and 980nm Diode lasers to treat tooth hypersensitivity did not change the SBS of metal orthodontic brackets to the enamel and thus, are harmless to use for orthodontic patients.