Er:YAG激光不同手具和照射距离对牙本质小管封闭效果的体外研究

The effects of different handpieces and distances of Er:YAG laser irradiation on dentinal tubule sealing-an in vitro study

目的:比较Er:YAG激光以不同手具和不同照射距离处理时对牙本质小管的封闭效果。方法:制备2 mm厚的牙本质片90个,采用0.5 mol/L EDTA去除玷污层以建立牙本质过敏症模型后,将其随机分为1个空白对照组和8个实验组(n=10);8个实验组用聚焦式(R02)和散焦式(R14)手具分别在1、2、3、4 cm处激发Er:YAG激光照射牙本质片。激光照射后,用扫描电镜(SEM)观察所有样本的牙本质小管形态,并应用Image-Pro Plus 6.0图像分析软件计算其牙本质小管的暴露面积和封闭率。结果:SEM观察见对照组牙本质小管形态完整、均匀开放;两种手具在照射距离1 cm时,牙本质小管口形态均受到破坏;2 cm时,R02手具组的牙本质小管仍有开放,而R14手具组多呈现闭合状态;在3~4 cm时,两种手具组的牙本质小管均封闭,且在牙本质表面有熔融层形成。图像分析结果显示,随着照射距离的增加,两种手具的牙本质小管暴露面积均呈现递减趋势,而其封闭率则均呈递增趋势,且2、3、4 cm组与对照组比较,P<0.05;在2 cm距离照射时,R14手具组的牙本质小管封闭效果优于R02手具组(P<0.05)。结论:Er:YAG激光照射对牙本质小管有一定封闭作用,且不同手具和照射距离均可影响Er:YAG激光对牙本质小管的即刻封闭效果。

AIM： To compare the effects of different irradiation modes and distances of Er： YAG laser irradiation on dentinal tubule sealing with focusing handpiece（R02） and the defocusing handpiece（R14） of Fotona laser therapeutic instrument.METHODS： 90 dentin discs with the thickness of 2 mm were prepared and etched with 0.5 mol/L EDTA to establish the dentine hypersensitivity models.Then the discs were randomly divided into a blank control group and 8 experimental groups（n = 10）.The R02 and the R14 were used to deliver Er： YAG laser irradiation to the dentin discs at the distance of 1 cm,2 cm,3 cm and 4 cm respectively.The dentinal tubule were observed with SEM,and the exposed area and the sealed rate of dentinal tubules were evaluated with Image-Pro Plus 6.0 software.RESULTS： The dentinal tubules in the control group were intact and open uniformly,while the dentinal tubules were destroyed when the dentin discs were exposed to the Er： YAG laser at 1 cm whether with R02 or with R14.In the 2 cm group,the dentinal tubules were still open with R02 while they were closed with R14.The dentinal tubules were sealed well and the melt layer formed over the dentin when exposed to the Er： YAG laser at 3 cm and 4 cm with both handpieces.The exposure area of the dentinal tubules decreased and the seal rate of dentinal tubules increased with the Er： YAG laser irradiation by R02 or R14 and with the distance increase（For the exposur area and seal rate,between the control group and 2 cm,3 cm or 4 cm groups,P 〈 0.05）.Moreover,the sealing effects with R14 at 2 cm were better than that with R02 at 2 cm（P 〈 0.05）.CONCLUSION： Er： YAG laser irradiation can seal the dentinal tubules,and the immediate sealing effects can be influenced by irradiation handpiece and irradiation distance.