Nd:YAG激光联合脱敏牙膏对牙本质小管的封闭效果评价

Combined Occluding Effect of Nd:YAG Laser and Desensitizing Toothpaste on Human Dentinal Tubules

目的评价Nd:YAG激光与脱敏牙膏联合应用对牙本质小管的封闭效果。方法将6颗完整的新鲜拔除的人第三磨牙制备成0.8 mm厚牙本质片后,每个牙本质片又被分为四部分,并随机分为四组分别为:对照组(A组),对牙本质片不做任何处理;Nd:YAG激光组(B组),仅采用激光对牙本质进行处理,激光功率1 W,频率15 Hz,脉宽150μs,照射时间10 s,六个循环;激光联合脱敏牙膏组(C组),采用脱敏牙膏刷牙片后,再用激光对牙本质片进行照射;激光联合脱敏牙膏后酸蚀组(D组),牙本质片先经激光联合脱敏牙膏处理后,再浸泡在可口可乐液中酸蚀5 min。扫描电镜观察各组牙本质片,根据牙本质表面形态和牙本质小管口开放的面积对牙本质片进行盲法评分并进行统计学分析。结果牙本质表面封闭效果:激光联合脱敏牙膏组优于单纯Nd:YAG激光组;单纯Nd:YAG激光组优于对照组,组间的封闭效果比较,差异具有统计学意义(P<0.01)。而激光联合脱敏牙膏后酸蚀组与未酸蚀组的封闭效果比较,差异无统计学意义(P>0.05)。结论 Nd:YAG激光与脱敏牙膏联合应用能在牙齿表面形成熔融样再结晶保护层,较单独使用Nd:YAG激光能更好的封闭牙本质小管,并且该保护层具有一定抗酸蚀能力,使封闭效果更加持久。

Objective To evaluate the combined occluding effect of Nd ： YAG laser irradiation and desensitizing toothpaste on human dentinal tubules. Methods Six freshly extracted intact human third molars were selected and 0. 8 mm-thick dentin slices were prepared. Each slice was sectioned into four parts and randomly divided into four groups ： Group A ： the control group, Group B ： the direct laser group, of which the dentin samples were directly irradiated withNd： YAG laser （ parameters ： 1 W, 15 pulses/s, 150 μS and six circles） for 10 s, Group C ： the laser plus desensitizing toothpaste group, of which the dentin samples were firstly brushed with desensitizing toothpaste, then irradiated with theNd ： YAG laser of the same parameter settings as those of Group B, and Group D ： the acid-etching group, of which thedentin samplesweretreated firstly in the same process as that of Group C and then immersed in Coca-cola liquidfor 5min. All of the dentin samples in eachgroupwere observed with scanning electron microscopes and photographed. Results It was observed with SEM that all the dentinal tubule orifices were open and the diameters of them were uniform in Group A. In Group B, some of the dentinal tubules were covered with a porous discontinuous melted recrystallization protective layer, but certain dentinal tubules were still open. In Group C, the dentin surface showed melting -like changes and was covered with a porous discontinuous melted recrystallization protective layer. Compared with Group B, Group C had much smaller porosity of protective layer and diameter of uncovered dentinal tubules. In Group D, the morphology of dentin Surface did not change significantly while beingcompared with that of Group C. Conclusions Combinedapplication of Nd ： YAG laser and desensitizing toothpaste will produce betteroecluded effectof dentinal tubules thansole usage of Nd ： YAG laser, and the melted recrystallization protective layer formed due to the combination of laser and desensitizing toothpaste is acid resistant to some extent, which results in more lasting desensitizing effect.