Evaluation of the effect of diode laser used for dental desensitization on dentin shear bond strength of resin cement

Introduction
Laminate veneers are used to address various esthetic concerns. The preparation causes dentin exposure, and exposed dentinal tubules lead to hypersensitivity after veneers cementation. Diode laser is used for dental desensitization, but its application on dentin before veneer placement has not been investigated.

Objectives
This study aimed to assess the impact of three diode laser wavelengths on dentin shear bond strength after resin cementation.

Material and methods
Forty molars were divided into four groups (10 samples in each group). Dentin was exposed, and resin cylinders were cemented using resin cement. In group 1, no laser was applied before cementation. In group 2, cylinders were cemented after applying a 660 nm wavelength with 250 mW output power. In group 3, cylinders were cemented after applying a 635 nm wavelength, operating at a power output of 50 mW. In group 4, cylinders were cemented after applying a 808 nm wavelength, operating at a power output of 50 mW. Shear bond strength testing was conducted at a rate of 0.5 mm/min until bonding failure occurred. Statistical analysis was performed using one-way ANOVA test, with a significance level set at 0.05.

Results
The control group had a mean dentin shear bond strength value of 26.1 ± 7.2 MPa, while the diode laser groups, i.e., 660 nm, 635 nm, and 808 nm demonstrated a mean value of 23.0 ± 7.0 MPa, 22.3 ± 7.0 MPa, and 22.4 ± 6.5 MPa, respectively. No significant difference in dentin shear bond strength was observed among the groups.

Conclusions
Diode laser does not affect dentin shear bond strength when used before veneers cementation.