关键词: Er:YAG激光, 牙本质, 扫描电镜, 剪切粘结强度

Abstract: Objective To research the effect of Er:YAG laser irradiation on dentin bonding strength. Methods Forty extracted human premolars or molars were randomly divided into 4 groups : group A，acidetching group (35％ phosphoric acid); group B，Er:YAG laser group; group C，Er:YAG laser + acidetching group; group D，control group. Two teeth selected randomly from each group were cut into 3 mm dentin slices, then observed using scanning electron microscopy(SEM）after treatment. The remaining teeth were prepared into unified dentin bonding surfaces, then combined with resin to test shear bond strength. Results SEM showed that apparent changes occurred to dentin morphology after treatment. The results of statistical analysis showed that group A had the highest shear bond strength (16.03±6.56) MPa and was followed by group C (13.21±6.08) MPa, but there was no significant difference between them（P＞0.05）.Group D had the lowest shear bond strength(4.52±1.02) MPa, and there was no significant difference between group D and group B (7.91±4.56) MPa（P＞0.05）, while there was a significant difference between group D and group A and group C（P<0.05）. Conclusion Compared with Er:YAG laser irradiation alone, acid etching after laser irradiation can enhance the shear bond strength between dentin and resin.

Key words: Er: YAG laser, dentin, SEM, shear bond strength