The influence of Er:YAG laser treatment on the shear bond strength of enamel and dentin: a systematic review and meta-analysis

Objectives: Tooth preparation is one of the factors that affect the bond strength of composite to teeth, and the method of preparation affects dentin morphology. Several disadvantages have been observed for the conventional technique. Currently, Er:YAG laser is a good treatment option and has been used to prepare hard dental tissue; it enables conservative preparation without damage to the pulp. Though Er:YAG laser is a promising alternative for preparation of the dentin surface, the bond strengths of Er:YAG-lased tooth substrates to composite reported in the literature have been confusing and even contradictory. The aim of the present study was to investigate the effect of Er:YAG laser irradiation, compared with conventional methods, on the shear bond strength of enamel and dentin. Method and materials: The databases PubMed, EMBASE, Springer, Wiley-Blackwell, EBSCO, and the China Academic Journals Full-text Database were searched for relevant studies in English or Chinese. Full-text articles were selected that involved shear bond strength after using the Er:YAG laser and conventional methods. Review Manager 5.0 was used to estimate the effects of the results among selected articles. Forest plots, sensitivity analyses, and bias analyses were also conducted for the articles. Results: Both in dentin and in enamel, the shear bond strength after using Er:YAG laser was significantly higher than that of the blank control (conventionally treated) group. Differences were not significant between studies that used burs in comparison with phosphoric acid. There was high heterogeneity of shear bond strength between different groups, and low numbers of studies and contradictory results may be the main reasons for this. A funnel plot indicated that some publication bias existed. Conclusion: The shear bond strength after Er:YAG laser preparation was significantly higher than that of the blank control (conventionally treated) group. Er:YAG laser is a safe and convenient alternative procedure, and has some advantages over traditional methods. Keywords: dentin, enamel, Er:YAG laser, meta-analysis, shear bond strength