Experimental Study On Sealing Effect Of Bioactive Glass On Dentin Tubule

Dentin hypersensitivity is a short,sharp pain that occurs when teeth are stimulated by mechanical,chemical,temperature,osmotic pressure and other factors in the physiological range.It is not an independent disease,it is a common symptom of a variety of diseases.With the expansion of the indication range of dental retention in adults and the development of dental restoration technology,dentin hypersensitivity has been in a high state.The treatment of dentin sensitivity mainly depends on occluding the dentine tubules and blocking the nerve conduction in the tubules according to the hydrodynamic theory.At present,the common novel desensitizing agents mainly include casein phosphopeptide-amorphous calcium phosphate(CPP-ACP),hydroxyapatite,bioactive glass and the like.Minqing Ao is a kind of fluoride-free 45S5 bioactive glass,and the main component is phosphosilicate,which is a safe bioactive material.It could exchange ions with human body liquid,release calcium and phosphorus plasma,produce calcium and phosphorus precipitates through a series of inorganic chemical reactions,and form hydroxyapatite eventually which occlude dentin tubules and reduce dentin sensitivity.BioMinF is a kind of fluoride-containing 45S5 bioactive glass,which is mainly composed of calcium fluorophosphosilicate.It can form fluorapatite instead of hydroxyapatite at the reaction interface,occluding dentin tubule and relieving dentin sensitive symptoms.In this experiment,the sensitive dentin model was treated with Minqing Ao and BioMinF.The sealing effect of two kinds of bioactive glass on dentin tubule was compared by scanning electron microscopy.The ability of resisting acid challenge of acid drink and brushing wear was compared to provide theoretical reference for the reasonable selection and application of bioactive glass.The main contents of the experiment are as follows: Objective: The sealing effect of Minqing Ao and BioMinF on dentin tubule was observed by scanning electron microscope,and the ability of two kinds of bioactive glass to resist acid challenge and brush tooth wear were compared.Methods: 78 third molars were used to prepare dentin disc.After removing the smear layer with 6% citric acid,they were divided into four groups according to different desensitizers: Minqing Ao(A),BiominF(B),distilled water(C)and blank group(D).According to different treatment methods and treatment time,Minqing Ao group,BiominF group and distilled water group were divided into four subgroups: immediate group(1),long lasting group(2),wear group(3)and acid etching group(4).They were divided into 13 groups and 6 samples in each group.Scanning electron microscopy(SEM)was used to observe the sealing effect of dentin tubules in each group.Results: The results of SEM showed that the exposure rates of dentin tubules in Minqing Ao immediate group,BioMinF immediate group and distilled water immediate group,were A1(11.78±1.92%),B1(5.21±1.78%),C1(15.03±4.73%),respectively.The difference was statistically significant.The exposure rate of dentine tubule in the 2-week of Minqing Ao,BioMinF and distilled water was A2(2.24±0.64%),B2(1.43±0.67%),C2(5.09±1.48%),the difference between A2 and C2,B2 and C2 was statistically significant.The exposure rate of dentine tubules in the wear group of Minqing Ao,BioMinF and distilled water was A3(3.01±0.73%),B3(1.47±0.63%),and C3(4.05±0.72%).The difference between B3 and C3 was statistically significant.The exposure rate of dentine tubules in Minqing Ao acid-etching group,BioMinF acid-etching group and distilled water acid-etching group were A4(7.86±0.92%),B4(1.48±0.58%),C4(14.62±3.03%),respectively,and the difference between groups was statistically significant.The exposure rate of dentine tubule in group D(15.00±3.51%)was statistically significant with C2 and C3.But there was no significant difference between group D and group C1,group D and group C4.The mineralized deposits were observed in the dentin tubules of Minqing Ao,BioMinF and distilled water in longitudinal section of dentin,and the occluding depth deepened with the prolongation of time,and the two bioactive glasses had strong tolerance to tooth brushing wear,and there was no obvious change in the occluding depth after brushing teeth.After acid etching,the occluding depth of the two materials decreased,and the degree of decrease of Minqing Ao was more significant than BioMinF.Conclusions:(1)Both Minqing Ao and BioMinF could significantly reduce the exposure of dentin tubule to dentin tubule.With the prolongation of action time,the effect is better.They could be used in the long-term treatment of dentin sensitive patients.(2)BioMinF is better than Minqing Ao in immediate sealing effect,but there is no significant difference in long-term effect.(3)Both Minqing Ao and BioMinF have good wear resistance,and the correct tooth brushing mode and normal tooth brushing pressure will not reduce the effect of the two bioactive glasses.(4)BioMinF has better resistance to acid challenge than Minqing Ao.So,BioMinF is more suitable for dentin sensitive patients who have the habit of eat acid foods and drinks.