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@#Dentin hypersensitivity is mainly associated with abrasion, wear, acid etching, cracking, wedge-shaped defects, enamel hypoplasia, caries, a lack of neck enamel, and cementum coverage accompanied by gingival recession, resulting in direct exposure of dentin tubules to the oral environment. Dentin hypersensitivity is mainly treated by sealing the exposed dentin tubules and reducing the excitability of the pulpal nerves. Laser therapy, as a safe, fast and convenient treatment measure, has achieved good results both alone and in combination with other medicines and has attracted increasing attention. This paper reviews the research progress in the treatment of dentin hypersensitivity using several common laser therapy mechanisms with parameter selections in various scopes of application. A review of the literature shows that the Nd:YAG laser has a strong penetrating power and a large thermal effect and can denature and coagulate proteins in dentin tubules in a very short time; while the CO2 laser causes little damage to the dental pulp and has an obvious immediate curative effect by high absorption of water molecules in hydroxyapatite and the dentin surface is melted and recrystallized; the Er:YAG laser has high water absorption and a large thermal effect and can block the tubules by evaporating the fluid in the tubules and depositing salts; Er, Cr:YSGG laser energy can be fully absorbed by hydroxyapatite and water and result in desensitization by cutting hard tissues and melting periodontal dentin of the tube simultaneously; The Ga-Al-As semiconductor laser and He:Ne laser are low energy. The laser dosage mainly changes the permeability of nerve fibers to potassium and sodium ions and depolarizes the nerve fibers, producing an analgesic effect. The combination of a laser with a desensitizer can improve the clinical efficacy of treating dentin hypersensitivity.
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Objective To observe the sealing effect of transient pinus massoniana bark extract (PMBE)pre-coating on dentin tubules and its wear resistance so as to provide an experimental basis for PMBE to be used to prevent and treat dentin hypersensitivity.Methods The model of dentin hypersensitivity was established by acid etching method.The samples were transient pre-coating with 80 g/L of PMBE ethanol solution,and then some of them experienced brushing wear treatment with ethanol group and fluorine vanish group as negative and positive controls.The surface and profile morphologies of the samples were observed using field emission scanning electron microscope (FESEM)in each group.The area of dentin tubular openings (ADTO)and percentage area of dentin tubular openings (PADTO)were also measured.Results The dentin tubules were opened completely and the lumen of dentin tubules was empty in ethanol group.The dentin tubules were completely or basically closed and some films or plugging could be seen in the lumen of dentin tubules in fluorine vanish/immediate group and PMBE/immediate group.The dentin tubules were partly opened and some wear marks could be seen on the dentin surface in fluorine vanish/wear groups,PMBE/wear groups.ADTO and PADTO in ethanol group were significantly higher than those in fluorine vanish groups and PMBE groups (P＜0.05).ADTO and PADTO did not significantly differ between fluorine vanish/wear groups and PMBE/wear groups (P＞0.05),which were all significantly higher than those in fluorine vanish/immediate group and PMBE/immediate group (P＜0.05).Conclusion Local transient pre-coating of PMBE ethanol solution can achieve fine immediate sealing effect of dentin tubules and some degree of wear resistance.
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Introdución: se utilizó un modelo in vitro, para medir la conductancia hidráulica en discos de dentina humana, tratados con ácido oxálico por 15, 30 o 60 s y la mantención del efecto oclusivo, medido a los 7 y 14 días post aplicación. Métodos: 45 discos dentinarios de 1mm de grosor fueron obtenidos de terceros molares humanos libres de caries, en inoclusión, de pacientes entre 16 a 30 años de edad. Los discos fueron divididos en tres grupos de estudio (n = 15), dependiendo del tiempo de aplicación de una solución comercial de desensibilizante dentinario (DD) a base de oxalato (BisBlock®), que contiene Ë 5% ácido oxálico pH 1,5-1,8: grupo A aplicación del agente por 15 s, grupo B aplicación por 30 s y grupo C por 60 s. La conductancia hidráulica de cada disco fue calculada posterior al grabado ácido, lo que corresponde a la máxima permeabilidad de dicho disco (100%), inmediatamente tras la aplicación del ácido oxálico y tras siete y 14 días de mantención en suero fisiológico.El análisis estadístico se hizo mediante test de ANOVA y post hoc de Games-Howell. Resultados: 35,46 ± 23,41% para el grupo A, 36,34 ± 15,88% para el grupo B y 24,99 ± 14,99% para el grupo C, por lo que la utilización de DD por 15, 30 ó 60 s generó una disminución en la permeabilidad que fue estadísticamente significativa (p Ë 0,05). Conclusiones: el DD fue eficaz en reducir la conductancia hidráulica independiente del tiempo de aplicación, siendo esta reducción sólo temporal, ya que tras siete días la permeabilidad retorna a valores cercanos a los iniciales.
Introduction: an in vitro model was used to measure the hydraulic conductance in human dentin discs treated with oxalic acid for 15, 30 or 60 s maintaining the occlusive effect and measuring 7 and 14 days after application. Methods: 45 dentin discs measuring 1 mm thick were obtained from human third molars which were free of caries and in no occlusion; the samples were obtained from patients aged 16 to 30 years. Discs were sorted out into three study groups (n = 15) depending on the time of application of a commercial solution of oxalate-based dentin desensitizer (DD) (BisBlock®) which contains Ë 5% oxalic acid of 1.5-1.8 pH: in group A the agent was applied for 15 s, in group B it was applied for 30 s, and in group C for 60 s. The hydraulic conductance of each disc was calculated after acid etching, which corresponds to the maximum permeability of discs (100%) after immediate application of oxalic acid, as well as seven and fourteen days of storage in saline solution. The statistical analysis was done with ANOVA test and post-hoc Games-Howell test. Results: 35,46 ± 23.41% in Group A, 36.34 ± 15.88% in Group B and 24.99 ± 14.99% in Group C, showing that the use of DD for 15, 30 or 60 s decreased permeability in a statistically significant manner (p <0.05). Conclusions: DD was effective in reducing hydraulic conductance regardless of application time, but this reduction was temporary only, since after seven days permeability returns to values close to those of baseline.
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Dentin , Diffusion , Oxalic Acid , PermeabilityABSTRACT
ABSTRACT:Objective To observe the structural changes of dentin irradiated with Nd:YAG laser under dif-ferent parameters and the changes of calcium-phosphorus ration,and evaluate the optimal parameters of Nd:YAG laser in treating dentin hypersensitivity (DH).Methods The model of dentin hypersensitivity was established by acid etching method.Samples were irradiated with Nd:YAG laser under different parameters.The morphological alterations of the dentin surfaces and Ca-P ratio were examined with scanning electron microscopy (SEM)combined with energy dispersive X-ray microanalysis.Results Compared with those in the control group,dentinal tubules could be blocked partially or totally with no cracks in A-C (30 mj,5 Hz),(30 mj,10 Hz)and (50 mj,5 Hz)groups. Dentinal tubules could be entirely blocked but with cracks in D (50 mj,10 Hz)and E (80 mj,5 Hz)groups.Dentin was carbonized in F (80 mj,10 Hz)group.Compared with that in the control group,Ca-P ratio was decreased sig-nificantly (P <0.05).Conclusion The suitable energy parameter of Nd:YAG laser in treating dentin hypersensi-tivity is (30 mj,10 Hz)and (50 mj,5 Hz).