Influence of Diode Laser Irradiation on Shear Bond Strength of Activa™ and Composite Resin Restorations in Primary Molars: An in Vitro Study.

Abstract

Aim:The aim of this study was to evaluate the influence of diode laser irradiation on the bond strength of two esthetic restorative materials; Activa bioactive restoration and composite resin. Materials and Methods: 104 primary molars were collected and divided into two main groups (n=52) (Laser and No laser). Teeth were mounted in acrylic molds and prepared to expose enamel and dentin surfaces. Samples of each group were randomly distributed into 4 subgroups: Activa + enamel, Activa + dentin, composite + enamel and composite + dentin. Enamel samples were etched, while universal adhesive was used for Activa and composite samples in dentin. Diode laser irradiation (980nm wavelength, 1W power, continuous mode) was applied after adhesive application and before polymerization. After thermocycling for 500 cycle, microshear bond was measured using universal testing machine and values were obtained in MPs. Statistical analysis was done using three ways ANOVA. Results: Mean bond strength of enamel samples were significantly higher than dentin samples (p<0.05). In Activa bioactive restoration samples, diode laser irradiation significantly reduced microshear bond strength in enamel and dentin. Irradiation with diode laser did not significantly improve the mean microshear bond strength in enamel and dentin composite samples. Conclusion: Diode laser irradiation did not improve bond strength of composite restorations when applied before adhesive polymerization of primary teeth and had negative effect on bond strength of Activa bioactive restorations.