Effects of microsurface structure of bioactive nanoparticles on dentinal tubules as a dentin desensitizer.

In this in vitro study, spherical mesoporous bioactive glass nanoparticle (MBGN) and non-porous bioactive glass nanoparticle (BGN) were fabricated. The impact of mesopores on dentinal tubule occlusion and bioactivity was compared to examine the potential of these materials in alleviating dentine hypersensitivity (DH). MBGN, dense BGN were synthesized by sol-gel methods and characterized. Bioactivity and ion dissolution ability were analyzed. Twenty-four simulated sensitive dentin discs were prepared and randomly divided into three groups (n = 8 each); Group 1, no treatment; Group 2, Dense BGN; Group 3, MBGN. Then, four discs per group were treated with 6wt.% citric acid challenge to determine the acidic resistance. The effects on dentinal tubule occlusion were observed by FESEM. The microtensile bond strength (MTBS) was also measured. Cytotoxicity was examined using the MTT assay. According to the results, dense BGN without mesopore and MBGN with mesopore were successfully fabricated. Dense BGN and MBGN occluded the dentinal tubule before and after acid challenge. However, only MBGN formed a membrane-like layer and showed hydroxyapatite formation after soaking SBF solution. There were no significant differences in MTBS among dense BGN, MBGN (P>0.05). The cell viability was above 72% of both materials. The higher bioactivity of MBGN compared with that of dense BGN arises from the structural difference and it is anticipated to facilitate dentin remineralization by inducing hydroxyapatite deposition within the dentinal tubule.

The role of ionic release from NovaMin (calcium sodium phosphosilicate) in tubule occlusion: an exploratory in vitro study using radio-labeled isotopes.

OBJECTIVE: The primary objective of this work was to develop a method of quantifying the levels and source of calcium and phosphate deposited on dental hard tissue from a novel calcium phosphosilicate (NovaMin) material using neutron activation analysis (NAA). A second objective was to explore the utility of radiotracing to determine dentin porosity following exposure to calcium phosphosilicate. METHODS: Neutron activation was used to create isotopes of Ca and P in the calcium phosphosilicate particles. Gamma radiation emitted from these isotopes was used to identify and measure their uptake (concentration) onto dental hard tissue. Three experiments were conducted to explore calcium and phosphate uptake to dental hard tissue: 1) a dose response to quantify the relative levels of calcium and phosphate deposited on dental hard tissue as a function of calcium phosphosilicate dose; 2) the effect of calcium phosphosilicate particle size on the relative levels of calcium and phosphate uptake; and 3) the permeability of calcium phosphosilicate-treated dentin by employing the radiotracer technetium. For all experiments, extracted bovine incisors were employed as the test substrate. RESULTS: The results indicate there is a strong dose relationship between the wt% and particle size of calcium phosphosilicate in the dentifrice formulation and new Ca and P deposition. At above 5.0 wt% calcium phosphosilicate, there appears to be an exponential increase in the number of counts from the tooth surface. Finer particle size calcium phosphosilicate appears to deposit much higher levels of Ca and P than the larger range of particle sizes. The results from the technetium study show that when treated with the dentifrice slurry containing calcium phosphosilicate, dentin shows only a slight amount of technetium infiltration, indicating a lowering of dentin permeability. CONCLUSION: This exploratory study has demonstrated that NAA and the use of radio isotopes have utility in monitoring the uptake of Ca and P into both dentin and enamel tooth structure. The data generated from these studies have shown that there is a dose dependence and particle size effect for calcium phosphosilicate on the deposition of calcium and phosphate to dental hard tissue.

Estudio de la eficacia y persistencia del efecto desensibilizante de una pasta dentrífica con nitrato potásico al 5% / No disponible

Se ha realizado un estudio clínico para evaluar la eficacia (..) (AU)

A clinical study was performed with the objective (..) (AU)

Estudio de la capacidad selladora de dos diferentes materiales utilizados como agentes para tratar la sensibilidad dentinal / No disponible

Se realiza un estudio comparativo para evaluar la capacidad de sellado tubular de dos diferentes agentes desensibilizantes a base de resinas o composites y comparar su grado de efectividad al utilizarlos. Se realiza una caracterización del comportamiento de los agentes terapéuticos que contiene una base de composite, glutaraldehido y polietilenglicol in vitro, a través de microscopia electrónica, midiendo él numero de superficies o canalículos obliterados, valorando así su capacidad de sellado. Basado en estos datos se hace un análisis de la capacidad selladora de los diferentes agentes y finalmente se compara la eficiencia de sellado, considerando cual tiene buenos resultados como agente desensibilizante. Encontramos excelentes resultados en los materiales testados en cuanto al sellado de los canalículos dentinarios en este estudio in vitro (AU)

A comparative study was performed with the objective to evaluate the capacity of two different desensiting agents based on resins or composites and to compare their degree of efficiency as a sealer.There is realized a characterization between the therapeutic agents that contains a base of composite, glutaraldehide and polietilenglicol in Vitro, across electronic microscopy, measuring the number of sealded surfaces, valuing by this way their capacity to seal. Based on this information an analysis of the capacity to seal of the different agents and finally the efficiency to be compared of sealed, considering which has good results as a disuniting agent. We found good results with the agents evaluated as a sealer with this in vitro study (AU)