不同染液对Nd：YAG激光封闭牙本质小管效果的影响

摘要

AIM:To observe the occluding effects of Nd:YAG laser irradiation with different dyes on dentin-al tubules.METHODS:4 freshly extracted first molars were collected,the enamel of their crowns and the cementum of their roots were removed with low speed diamond disk,thus dentin was exposed.The coronal dentin surface of each tooth was divided into 4 areas of 2 mm ×3 mm.The dentin surface were treated with 270 g/L EDTA,then the 4 areas were coa-ted with nothing(control),20 g/L methyl violet,ink and 20 g/L methylene blue respectively,then irradiated by Nd:YAG laser with 120 mJ,5 Hz for 20 s,the corresponding energy density was 200 J/cm2 .The specimens were processed and ob-served using SEM.Photoes were taken under 1500 ×and 3000 ×views,the dentinal tubule occlusion rates were calculat-ed and the dentinal tubule diameters were measured.RESULTS:In control,20 g/L methyl violet,ink and 20 g/L meth-ylene blue groups,dentinal tubule occlusion rates(%)were 10.01 ±1.71,2.72 ±0.70,11.18 ±2.34,36.14 ±6.30, respectively(between each 2 groups,P<0.05).Dentinal tubule diameters(μm)were 2.75 ±0.26,3.25 ±0.24, 1.61 ±0.13 and 1.32 ±0.14 respectively(between each 2 groups,P<0.05).CONCLUSION:20 g/L methylene blue solution can most obviously enhance the sealing effect of Nd:YAG laser on dentinal tubules.%目的：观察不同染液对Nd：YAG激光封闭牙本质小管效果的影响。方法：取4个新鲜拔除的第一恒磨牙，用低速金刚砂盘水平去除冠部牙釉质并暴露牙本质后，在每个牙本质样本的表面各划分出4个面积为2 mm ×3 mm的操作区（共16个区域）；分别用EDTA进行表面处理后，将16个区随机分配到4个组中（n＝4），其中不涂染液直接激光照射的样本为对照，其他3组样本分别涂20 g／L甲基紫、墨汁、20 g／L亚甲蓝后，用Nd：YAG激光以120 mJ、5 Hz（对应的激光能量密度为200 J／cm2）扫描式照射各操作区20 s；然后常规制备SEM标本，在SEM下观察，同时采集1500×和3000×视野下的典型图像，分别用于计算各组牙本质小管的封闭率和测量小管口的直径。结果：对照组、20 g／L甲基紫组、墨汁组、20 g／L亚甲蓝组的牙本质小管封闭率分别为（10．01±1．71）％、（2．72±0．70）％、（11．18±2．34）％、（36．14±6．30）％，各组间两两相比P＜0．05；小管口直径（μm）分别为2．75±0．26、3．25±0．24、1．61±0．13、1．32±0．14，各组间两两相比 P＜0．05。结论：20 g／L 亚甲蓝染液能明显增强Nd：YAG激光对牙本质小管的封闭作用。