脱敏剂和激光脱敏对牙本质表面形态、硬度和成分的影响

Effects of desensitizer and laser desensitization on surface morphology,hardness and composition of dentin

目的:探讨采用奥敏清脱敏剂和掺铒钇铝石榴石(Er∶YAG)激光及掺钕钇铝石榴石(Nd∶YAG)激光分别处理牙本质后对其表面形态、硬度、钙(Ca)和磷(P)含量以及Ca/P比值的影响,并阐明其可能的机制,为其用于临床牙本质敏感症的治疗提供参考。方法:收集18~20岁志愿者因阻生而拔除的新鲜第三磨牙32颗,制备2mm厚的牙本质片32个,将样本分为空白对照组、奥敏清组、Er∶YAG组和Nd∶YAG组,每组8个样本。除空白对照组外,其余各组样本采用17%EDTA去除玷污层建立牙本质敏感症模型,每个样本被线性切割机从中间对称分割为2个半圆形牙本质盘,一半采用显微硬度计测量各组牙本质表面显微硬度(SMH)值,一半采用扫描电子显微镜(SEM)观察其表面形态表现,并采用X射线能谱仪(EDS)分析样本牙本质表面Ca和P含量。结果:各组样本牙本质SMH值比较差异均无统计学意义(P>0.05)。SEM下观察,空白对照组样本牙本质表面无涂片层,小管较宽,表面光滑清洁;奥敏清组样本牙本质小管部分封闭,小管内可见阻塞物;Er∶YAG组样本牙本质小管很少或没有开放,大部分为部分或完全封闭的小管,表面可见熔融状改变;Nd∶YAG组样本牙本质小管部分或完全封闭,开放小管极少,表面呈熔融状。与空白对照组和奥敏清组比较,Er∶YAG组和Nd∶YAG组样本牙本质表面Ca和P含量明显升高(P<0.05);与空白对照组比较,奥敏清组样本牙本质表面Ca和P含量差异无统计学意义(P>0.05);与Nd∶YAG组比较,Er∶YAG组样本牙本质表面Ca和P含量差异也无统计学意义(P>0.05);各组样本Ca/P比值比较差异均无统计学意义(P>0.05)。结论:奥敏清脱敏剂、Er∶YAG激光和Nd∶YAG激光的应用不会引起牙本质表面硬度和Ca/P比值的变化,但Er∶YAG和Nd∶YAG激光可增加牙本质表面的Ca和P含量,改变牙本质表面的形态、组成和结构。

Objective:To investigate the effects of Aominqing desensitizer and two laser(Er∶ YAG and Nd∶YAG)treatments on the dentin surface morphology,hardness,and calcium(Ca)and phosphorus(P)contents and Ca/P ratio,to clarify the possible mechanisms,and to provide reference for its clinical application in the treatment of dentin sensitivity.Methods:The fresh third molars extracted because of impaction from the volunaeers aged 18-20 years old were collected.A total of 32 dentin slices of 2 mm were prepared;the samples were divided into blank control group,Aominqing group Er∶YAG group and Nd∶YAG group,and there were eight samples in each group.Except blank control group,the samples in other groups were used to establish the dentin hypersensitivity models by purifying the polluted layer with 17% EDTA.Each sample was cut by linear cutting machine from the middle symmetry into two semicircle dentin;the half was used to detect the dentin surface microhardness(SMH)values by microhardness meter,another half was used to observe the surface morphology and analyze the Ca and P contents with SEM and EDS was observed.Results:There were no significant differences in the SMH values of dentin samples between various groups(P>0.05).In blank control group,there was no smear layer on the dentin surface with wide tubules and smooth and clean surface;the dentin tubules of the samples in Aominqing group were partially closed,and obstructions were seen in the tubuless in Er∶YAG group the dentin tubules were little or no open,most of them were partially or completely closed tubules,the surface had the melting changes in Nd∶YAG group,the dentin tubules were partially or completely closed with few open tubules and the surface was molten.Compared with blank control group and Aominging group,the Ca and P contents in the samples in Er∶YAG group and Nd∶YAG were significantly increased;there was no statistically significant difference in the contents of Ca and P between and blank control group and Aclinsing group(P>0.05),and the difference between Er∶YAG group and Nd∶YAG group was not significant(P>0.05).The differences in the Ca/P ratios between various groups were not statistically significant(P>0.05).Conclusion:The application of Aominqing desensitization agent,Er∶YAG laser and Nd∶YAG laser can not cause the changes of dentin SMH and the Ca/P ratio,but the application of Er∶YAG and Nd∶YAG laser to dentin can significantly increase the contents of Ca and P and change the morphology,composition and structure of dentin surface.