Objective:To investigate the acid resistance of tooth hard tissues irradiated by different power outputs of Er,Cr∶YSGG laser.Methods:Samples in laser groups were irradiated using Er,Cr∶ YSGG laser with the power outputs of 2.5,3.5 and 5 W for enamel and 2 W,3 W and 4 W for dentin,respectively.The calcium and phosphate ion dissolved was measured after decalcification in lactate buffer solution for 24 h.The atomic percentage of calcium and phosphate on the surface of samples was examined by X-ray energy dispersive spectroscopy and the morphological changes were investigated by SEM.Results:In all laser groups of enamel samples except 2.5 W group calcium and phosphate ion dissolved less than in control group and block group (P＜0.05).There's no statistic difference between different power groups.Compared with control group and block group,Ca/P ratio increased(P＜0.05).There's no statistic difference of the atomic percentage of Ca and P on the surface of dentin samples between each 2 groups.SEM observation showed that the surface of the laser irradiated samples was rouph,the space among enamel fibers was increased,the dentin around dentinal tuble orifice was protruded and looked like collar flange.Conclusion:Er,Cr∶YSGG laser irradiation with a range of power is effective in increasing acquired acid resistance of dental hard tissue.There was no relationship between laser power outputs and acid resistance.%目的:探讨Er,Cr∶ YSGG激光照射能量与牙体硬组织抗酸性之间的关系.方法:采用2.5、3.5、5W激光照射牙釉质样本,2、3、4W激光照射牙本质样本.经0.1 mmol/L乳酸液浸泡24 h后检测钙磷溶出量,能谱仪检测样本表面钙磷原子百分比,SEM观察表面形态.结果:除2.5W牙釉质组,其余牙釉质和牙本质实验组钙磷溶出量显著低于对照组(P＜0.05),实验组间无明显差异.激光照射后牙釉质钙磷比增加,牙本质钙磷含量均无变化.SEM观察显示实验组样本表面粗糙,釉柱间隙增大,牙本质小管口周牙本管突出成袖口状.结论:一定能量的Er,Cr∶YSGG激光照射可使牙硬组织抗酸性提高.
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