【摘要】 目的　观察CO2 激光对牙本质小管的封闭作用。方法　用 10颗人新鲜离体牙制备牙本质块 ,第 1组 6颗牙 ,连续激光 ,断续输出 ,输出功率 1W ,光输出时间和间隔时间均为0 0 5s(0 0 5on off)。将标本分别置于距出光孔 1、2和 5cm处 ,每处 2颗牙 ;照射时间分别为 2 0、30和 6 0s,出光孔处光斑直径为0 4mm ,激光束发散角为 7 9°。第 2组 4颗牙 ,连续激光 ,输出功率 0 5W。将标本置于距出光孔处 2 0cm ,光斑直径 1mm ,分别用 2s、1 2 7J mm2 与 10s、6 36J mm2 各照射 2个标本。肉眼和扫描电镜观察牙本质表面的变化。结果　CO2 激光照射牙本质后 ,随能量密度的不同 ,可出现牙本质小管管腔阻塞、表面粗糙 ,小管被覆盖封闭、牙本质表面熔融 ,牙本质小管更加开放等不同的变化。结论　能量密度不同的CO2 激光 ,可对牙本质小管造成完全不同的效果 :开放或封闭更多还原

【Abstract】 Objective To investigate the dentin surface alterations caused by CO 2 laser irradiation. Methods Dentin pieces were prepared from 10 freshly removed human teeth. Teeth of the first experimental group were irradiated by continuous laser, with an output power of 1 W, 0 05 s on and 0 05 s off, alternatively. Samples were located at 1 cm, 2 cm or 5 cm distant from the laser apparatus. The irradiation time was 20 s, 30 s or 60 s. The diameter of light beam was 0 4 mm, with a scattering angle of 7 9°. Teeth of the second experimental group were irradiated by continuous laser, with an output power of 0 5 W. Samples were located at 20 cm distant from the laser apparatus, irradiated for 2 s or 10 s, with an energy density of 1 27 J/mm 2 and 6 36 J/mm 2, respectively. The diameter of light spot was 1 mm. The teeth were then routinely prepared for scanning electron microscopic examination. Results After CO 2 laser irradiation on the teeth, varying changes of the dentin surface were observed, according to different energy densities used: from obstructed dental tubules obstruction to melting and covering of dental tubules even to tubules opening. Conclusions Different changes of the dentin surface can be caused by CO 2 laser irradiation with varying energy densities: from dental tubules closing to opening. Our findings are of important meaning in understanding and performance of CO 2 laser therapy of dentin hypersensitiveness.更多还原