Hashiguchi K, Hashimoto K
Department of Oral Surgery, Hamamatsu University School of Medicine, Japan.
Okajimas Folia Anat Jpn. 1990 Oct;67(4):271-9. doi: 10.2535/ofaj1936.67.4_271.
The crystallographic alterations of the hydroxyapatite under the laser irradiation were evaluated by the x-ray diffraction pattern analysis and scanning electron microscopic observation. Recrystallization may occur in fused and resolidified dental enamel by the pulsed Nd: YAG laser irradiation. Two different grades of energy densities such as 400 pulses and 800 pulses were given to the powdered enamel. The irradiation was performed at a peak power of 500W with a pulse width of 10 msec.; the average output of 10W, spot size of 3mm and two pulses were given in every second. After the 800 pulses of Nd:YAG laser irradiation to the human dental enamel the x-ray diffraction pattern demonstrated both alpha-tricalcium phosphate and hydroxyapatite peaks. With the lower level of energy at 400 pulses, no significant differences were seen in the diffraction patterns between lased and unlased enamel. In scanning electron microscopic findings, there were no significant changes between lased and unlased enamel. When the unlased and lased enamel were exposed to acid solution, unlased enamel showed a honeycomb pattern, while the lased enamel showed preferentially removed prism core material.
通过X射线衍射图谱分析和扫描电子显微镜观察，评估了激光照射下羟基磷灰石的晶体学变化。脉冲Nd:YAG激光照射可能会使熔融并重新凝固的牙釉质发生再结晶。对粉末状牙釉质施加了400次脉冲和800次脉冲这两种不同等级的能量密度。照射以500W的峰值功率、10毫秒的脉冲宽度进行；平均输出功率为10W，光斑尺寸为3mm，每秒发射两个脉冲。在对人牙釉质进行800次Nd:YAG激光照射后，X射线衍射图谱显示出α-磷酸三钙和羟基磷灰石的峰。在400次脉冲的较低能量水平下，激光照射和未激光照射的牙釉质在衍射图谱上没有显著差异。在扫描电子显微镜观察结果中，激光照射和未激光照射的牙釉质之间没有显著变化。当未激光照射和激光照射的牙釉质暴露于酸性溶液中时，未激光照射的牙釉质呈现蜂窝状图案，而激光照射的牙釉质则优先去除棱柱核心材料。
