The Effect of Two Different Wavelengths of Diode Laser on the Shear Bond Strength of Composite to Dental Enamel after Bleaching Process: An In Vitro Study

TL;DR

This study examines how different laser wavelengths affect the bond strength between dental enamel and composite after bleaching.

Contribution

The study compares the effects of 970 nm and 445 nm lasers on enamel-composite bond strength after bleaching.

Findings

The 445 nm laser significantly reduced shear bond strength compared to other groups.

No significant difference was found between the control group and the 970 nm laser group.

Bleaching with a 445 nm laser weakens the bond between enamel and composite.

Abstract

Introduction: In recent years, tooth whitening has become one of the most popular ways of achieving the original tooth color. The effect of whitening gel can be improved through heat, light or laser. The bond strength between the enamel and the composite can be reduced through bleaching and laser radiation. The purpose of this study is to assess the shear bond strength of resin composite to enamel after a bleaching process using hydrogen peroxide, with and without a laser (970 nm and 445 nm lasers). Method: This study used 51 extracted anterior teeth without caries that were divided into three groups. A 40% hydrogen peroxide gel was used on the enamel of all teeth. The control group received bleaching without a laser. Both the second and third treatment groups received bleaching with a laser, one with 970 nm and the other with 445 nm. After the bleaching process, all groups had etching, bonding and curing of the composite performed. Lastly, the shear bond strength between the enamel and the composite was measured and the failure modes were recorded. The data were compared using a one-way ANOVA test. Results: The mean shear bond strength between the enamel and the composite in the 445 nm group three (445 nanometer) was significantly lower than the other groups (p < 0.05). There was no significant difference between the control and the 970 nm groups (p = 0.2). Conclusion: According to the laser wavelengths and parameters that were used in this study and the results of this study, office bleaching with a 445 nm laser weakened the shear bond strength between the enamel and the composite.

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