Kimura Y, Yu D G, Fujita A, Yamashita A, Murakami Y, Matsumoto K
Department of Endodontics, Showa University School of Dentistry, Tokyo, Japan.
J Periodontol. 2001 Sep;72(9):1178-82. doi: 10.1902/jop.2000.72.9.1178.
Only relatively few reports have described the morphological effects on bone produced by erbium,chromium: yttrium,scandium,gallium,garnet (Er,Cr:YSGG) laser irradiation, and none has investigated the atomic changes or estimated the temperature increases involved. The objectives of this study were to investigate the morphological, atomic, and temperature changes in irradiated areas during and after laser irradiation, and to evaluate the cutting effect on canine mandibular bone in vitro.
Two canine mandibular bones were cut into 3 to 5 cm pieces and irradiated by an Er,Cr:YSGG laser utilizing a water-air spray at 5 W and 8 Hz for 10 or 30 seconds. During and after laser irradiation, temperature increases in the irradiated areas were measured by thermography. The samples were then observed by stereoscopy and scanning electron microscopy to determine morphological changes and by energy dispersive x-ray spectroscopy to evaluate atomic alterations.
Regular holes or grooves having sharp edges and smooth walls were produced, but no melting or carbonization was observed. The maximum temperature increase was an average 12.6 degrees C for 30-second irradiation. The continuous time of a temperature increase of more than 10 degrees C was consistently less than 10 seconds. An atomic analytical examination revealed that the calcium:phosphorus ratio was not significantly changed between the lased and unlased areas (P>0.0 1).
These results showed that the Er,Cr:YSGG laser cuts canine mandibular bone effectively without burning, melting, or altering the calcium:phosphorus ratio of the irradiated bone.
仅有相对较少的报告描述了铒铬钇钪镓石榴石（Er,Cr:YSGG）激光照射对骨骼产生的形态学影响，且尚无研究调查其原子变化或估计所涉及的温度升高情况。本研究的目的是调查激光照射期间及照射后受照射区域的形态学、原子和温度变化，并在体外评估对犬下颌骨的切割效果。
将两块犬下颌骨切成3至5厘米的片段，使用水-空气喷雾，以5瓦和8赫兹的频率用Er,Cr:YSGG激光照射10或30秒。在激光照射期间及照射后，通过热成像测量受照射区域的温度升高。然后通过立体显微镜和扫描电子显微镜观察样本以确定形态学变化，并通过能量色散X射线光谱法评估原子改变。
产生了边缘锐利且壁光滑的规则孔洞或凹槽，但未观察到熔化或碳化现象。30秒照射的最大温度升高平均为12.6摄氏度。温度升高超过10摄氏度的持续时间始终小于10秒。原子分析检查显示，激光照射区域和未照射区域之间的钙磷比没有显著变化（P>0.01）。
这些结果表明，Er,Cr:YSGG激光可有效切割犬下颌骨，不会造成灼烧、熔化或改变受照射骨骼的钙磷比。
