Debonding of the orthodontic brackets; is diode laser a safer method? Experimental invitro study

Abstract

Bracket debonding remains a clinical challenge in orthodontics, particularly when removing ceramic brackets, due to the potential risk of enamel cracks and surface damage. Recently, laser-assisted techniques have been investigated to facilitate safer and less traumatic bracket removal. This study aimed to evaluate the effect of 940 nm diode laser irradiation on the debonding process of metallic and ceramic orthodontic brackets by assessing shear bond strength (SBS) and enamel surface morphology using scanning electron microscopy (SEM). Thirty two extracted human premolars were randomly divided into four experimental groups: Group A (Control–Metallic),Group B (Control–Ceramic),Group C (Laser–Metallic), and Group D (Laser–Ceramic).Brackets were bonded using a light-cured adhesive and subjected to diode laser irradiation at 940 nm, 1 W, for 5 seconds in the laser-treated groups. SBS was measured using a universal testing machine at a crosshead speed of 1 mm/min, and mean values were expressed in MPa. Enamel surface morphology was analyzed using SEM at 80× and 1000× magnifications. Statistical analysis was performed using one-way ANOVA and independent t-tests with a significance level of p < 0.05. Laser-assisted debonding significantly reduced SBS in metallic brackets (mean ± SD: 2.4 ± 0.3 MPa) compared with the control group (4.3 ± 0.4 MPa) (p < 0.05). In contrast, the difference between laser-treated and control ceramic brackets was not statistically significant. SEM observations revealed smoother enamel surfaces and fewer cracks in the laser-treated groups compared with controls. Diode laser–assisted debonding (940 nm, 1 W) effectively decreases shear bond strength for metallic brackets and minimizes enamel surface alterations, suggesting it is a promising adjunct for safer bracket removal. However, the technique’s effect on ceramic brackets appears limited at this power setting.