Objective To assess the effects of different application sequences of neodymium-doped yttrium aluminum garnet(Nd∶YAG)laser and the desensitizing toothpaste containing stannous fluoride on dentinal tubule occlusion.Methods Twelve intact third molars freshly extracted from human were selected and prepared into dentin slices with a thickness of 0.8 mm.Each dentin slice was subdivided into four small slices,three of which were etched with 6% citric acid and randomly assigned to the following three groups(n=12):(1)control group:no treatment;(2)Nd∶YAG+toothbrushing(TB)group:first irradiated with Nd∶YAG laser and then brushed with desensitizing toothpaste;(3)TB+Nd∶YAG group:first brushed with desensitizing toothpaste and then irradiated with Nd∶YAG laser.The Nd∶YAG laser irradiation were carried out at 1 W,15 pulses/s,and the pulse width of 150 μs for 10 s(for a total of 6 cycles).After the above treatment,the 12 dentin slices from the Nd∶YAG+TB and TB+Nd∶YAG groups were randomly assigned to four subgroups(n=3)and subjected to acid etching in the Coca-Cola solution for 0,5,10,and 15 min.A scanning electron microscope was used to observe and photograph the dentin slices in each group,and eight single-blinded examiners scored the slices according to uniform criteria.The analysis of variance was carried out to compared the scores between groups.Results Before acid etching,the dentin tubule occlusion scores of the Nd∶YAG+TB and TB+Nd∶YAG groups were(4.83±0.09) scores and(3.85±0.66) scores,respectively,which had no significant difference between each other(P=0.0590)and were higher than that[(0.10±0.07)scores]of the control group(both P<0.0001).The dentin tubule occlusion scores of the Nd∶YAG+TB group after acid etching for 5,10,and 15 min were(4.33±0.60)scores,(4.27±0.24)scores,and(3.63±0.07)scores,respectively,which were not significantly different from those[(4.04±0.10)scores,(3.76±0.59)scores,and(3.17±0.29)scores,respectively]of the TB+Nd∶YAG group(all P>0.05).In the Nd∶YAG+TB subgroup,the dentin tubule occlusion score after acid etching for 15 min was significantly lower than that before acid etching(P=0.0011).In the TB+Nd∶YAG group,there was no statistically significant difference in the score between before and after acid etching(P>0.05).Conclusions Nd∶YAG laser irradiation with appropriate parameters combined with the use of desensitizing toothpaste could produce an excellent occluding effect on dentinal tubules regardless of the sequence.However,brushing with desensitizing toothpaste followed by Nd∶YAG laser irradiation produced more consistent dentin sealing after acid etching.
目的 评估掺钕钇铝石榴石(Nd∶YAG)激光和含有氟化亚锡系统的脱敏牙膏不同应用顺序对牙本质小管封闭效果的影响。方法 选择12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,将每个牙本质片再分为4小片,取其中3小片,用6%的柠檬酸进行腐蚀,随机分配至以下3组(n=12):(1)对照组:无处理;(2)Nd∶YAG激光+牙膏(TB)组:先用Nd∶YAG激光照射,后用脱敏牙膏刷牙;(3)TB+Nd∶YAG组:先用脱敏牙膏刷牙,后用Nd∶YAG激光照射。Nd∶YAG激光照射参数均为:1 W,15脉冲/s,脉冲宽度150 μs,照射10 s,6个循环。经上述处理后,将Nd∶YAG+TB组和TB+Nd∶YAG组的12个牙本质片随机分配到4个亚组(n=3),分别在可口可乐液中接受酸蚀0、5、10、15 min。采用扫描电子显微镜观察各组牙本质片并拍片,由8名单盲检查员根据统一标准给出评分,采用方差分析对各组评分进行比较。结果 酸蚀前,Nd∶YAG+TB组和TB+Nd∶YAG组的牙本质小管封闭评分分别为(4.83±0.09)分和(3.85±0.66)分,均明显高于对照组的(0.10±0.07)分(P均<0.0001),Nd∶YAG+TB组与TB+Nd∶YAG组差异无统计学意义(P=0.0590)。Nd∶YAG+TB组酸蚀5、10、15 min牙本质小管封闭评分分别为(4.33±0.60)、(4.27±0.24)、(3.63±0.07)分,与TB+Nd∶YAG组的(4.04±0.10)、(3.76±0.59)、(3.17±0.29)分差异均无统计学意义(P均>0.05)。在Nd∶YAG+TB亚组中,酸蚀15 min牙本质小管封闭评分明显低于酸蚀前(P=0.0011)。在TB+Nd∶YAG组中,酸蚀前后牙本质小管封闭评分间差异无统计学意义(P>0.05)。结论 适当参数的Nd∶YAG激光照射结合使用脱敏牙膏,不论先后顺序,均可以产生良好的牙本质小管封闭效果,但是先用脱敏牙膏刷牙后用Nd∶YAG 激光照射组在酸蚀后的牙本质封闭效果更稳定。.
Keywords: acid etching; dentin hypersensitivity; neodymium-doped yttrium aluminum garnet; toothpaste.