| Objective:1.The effect of Langzhen tooth desensitizer on dentin hypersensitivity was observed and evaluated through in vitro studies and clinical trials,so as to provide a theoretical basis for its clinical use.2.Screening the appropriate energy parameters for the Er: YAG laser to seal the dentin tubules,studying the effects of diverse treatment methods of Langzhen desensitizer,Er: YAG laser and their combined application on the degree of dentin tubule sealing,and the content and ratio of calcium and phosphorus elements on the dentin surface,in order to explore the best desensitization approach and provide reference basis for clinical treatment of DH.Methods: This research consists of two parts.Namely the study on the treatment of dentin hypersensitivity with Langzhen tooth desensitizer,and the experimental study on the effect of Langzhen tooth desensitizer and Er:YAG laser on the surface of dentin.1.Study on the treatment of dentin hypersensitivity with Langzhen tooth desensitizer1.1 40 isolated premolars were prepared into dentin discs,and randomly divided into four groups according to the type of desensitizer: Langzhen,Aominqing,75%sodium fluoride glycerin paste,and blank control.The blank group was not treated.The samples of the other three groups were uniformly coated with desensitizer for5 minutes.The above four groups were randomly partitioned into two subgroups according to different treatment methods: immediate observation group(1)and wear group(2).The teeth brushing experiment was carried out on the sample of the wear group,the wear group are longitudinally inserted immediately.The sealing condition of dentin tubules in each group was observed by scanning electron microscope.1.2 151 teeth with dentin hypersensitivity from 60 patients were randomly divided into three groups: A(Langzhen),B(Aominqing),and C(75% sodium fluoride glycerin paste),with 20 people in each group,and the three groups of patients were treated with desensitization for 2 weeks.The sensitivity of the affected tooth immediately after treatment,2 weeks of treatment and 1,3 months after treatment were recorded,and the clinical efficacy of Langzhen and other two desensitizers were compared and analyzed.2.The experimental study on the impacts of Langzhen tooth desensitizer and Er:YAG laser on dentin surface.2.1 The 24 dentin discs were prepared from isolated premolars and randomly divided into 4 groups with 6 disks in each group.The control group was not irradiated,and the remaining samples were irradiated by Er:YAG laser according to the energy of 40 mJ,60 mJ,and 80 mJ,and the degree of tubule sealing was observed under a scanning electron microscope.2.2 Thirty dentin discs prepared by collecting isolated premolars,which were randomly divided into the following groups according to different treatments: F1(blank control group),F2(Langzhen single treatment),F3(Langzhen multiple treatments),F4(Er: YAG laser irradiation),F5(Langzhen + laser combined treatment)5 groups,SEM and EDXA were applied to compare the influences of different treatment methods on the degree of dentin tubule sealing,the content and ratio of calcium and phosphorus on dentin surface.Results: 1.Study on the treatment of dentin hypersensitivity with Langzhen tooth desensitizer.1.1 The dentin tubules of the blank control group were completely opened.In the immediate group and the abrasion group,the exposure rate of the dentin tubules of the three desensitizers was lower than that of the blank control group(P<0.05);the dentin tubules of Langzhen and Aominqing were exposed There was no significant difference in the exposure rate(P>0.05);the exposure rate of the dentin tubules of75% sodium fluoride glycerin paste was higher than that of the other two desensitizers(P<0.05).After abrasion,the opening rate of dentin tubules in each group increased,but they still had a sealing effect.1.2 The total effective rate of group A patients was higher than that of group C immediately after treatment,2 weeks after treatment and 1,3 months after treatment(P<0.05),there was no statistical significance in total effective rate between group A and B at these 4 time nodes(P>0.05).2.The experimental study on the effect of Langzhen tooth desensitizer and Er:YAG laser on dentin surface.2.1 The SEM image showed that melt layer appeared on the surface of the dentin in E2,E3 and E4 groups.The molten material made the dentin tubules shrink to different degrees,and most of the dentin tubules were completely covered.Among the three treatment groups,the E3 group had the best sealing effect,while the least dentin tubules were not completely covered.2.2 The exposure rate of dentin tubules in the F5 group was the lowest,which was statistically different from the other groups(P<0.05).While there was no statistically significant difference between the F3 and F4 groups(P>0.05);The tubule exposure rate of the dentin in F3 and F4 groups was lower than that in F2 group,and the difference was statistically significant(P<0.05);Compared with the blank control group,the contents of Ca and P elements in the F1,F2,F3,and F4 groups were all increased(P<0.05),yet the ratio of Ca to P had no significant change(P>0.05).Conclusion:1 Langzhen desensitizer can effectively seal dentin tubules,and has certain wear resistance,the clinical effect of treating dentin allergy is better than 75% sodium fluoride glycerin paste,which is similar to the desensitization effect of the Aominqing.2 Under the experimental conditions,the Er:YAG laser can achieve better sealing effect of dentin tubules with the energy parameter of 60 mJ.3 The combined treatment of Langzhen desensitizer + Er: YAG laser has the best sealing effect on dentin tubules;when Langzhen desensitizer and Er: YAG laser were applied to the surface of dentin,the content of Ca and P were increased,but the Ca/P ratio was not influenced. |
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