Effect of using 445 nm diode laser with different curing time on enamel shear bond strength of resin composite used for bonding orthodontic brackets. An in-vitro study

Was to evaluate the effect of 445 nm diode laser, using a bleaching handpiece, with different curing time on shear bond strength between resin composite used for bonding orthodontic brackets and enamel surface.

Twenty seven premolar teeth were selected and randomly divided into three equal groups according to the curing protocol of resin composite used for bonding orthodontic brackets (n = 9); Group I (control): light curing using LED for 20 s (C), Group II: laser curing using 445 nm diode laser, using a bleaching handpiece, for 20 s (L20), Group III: laser curing using 445 nm diode laser, using a bleaching handpiece, for 10 s (L10). Teeth were mounted in acrylic blocks and orthodontic brackets were bonded using Greengloo light cure resin composite (Ormco Corporations, USA). Teeth were mounted in a universal testing machine, shear bond strength was measured in MPa. Data were statistically analyzed by one-way ANOVA and Tukey's post hoc significance difference test were used to analyze the data.

Diode laser application for 20 s group showed the highest shear bond strength mean value (13.96 MPa), followed by the control group with mean value (13.35 MPa), with no significant difference between all groups.

445nm diode laser was proven to be efficient for bonding of orthodontic brackets. Using 445nm diode laser with shorter curing time have shown acceptable results that could still yield to better clinical outcomes with shorter treatment duration.