O Programa de Pós-Graduação em Odontologia da UFRGS

O Programa de Pós-Graduação em Odontologia da UFRG

Bismuth subsalicylate as filler particle for an experimental epoxy-based root canal sealer

Aim: To evaluate the influence of bismuth subsalicylate addition in different concentrations on theproperties ofan experimental epoxy-based root canal sealer. Methods: Bismuth subsalicylate in 20%, 40%, 60%, 80%, 100% and 120 wt% was added tothe sealer. Flow, film thickness, working time, setting time, dimensional change, sorption, solubility and cytotoxicity were evaluated according to ISO standard. Data were statistically analyzed by one-way ANOVA and Tukey’stest with a significance level of 5% for all tests. Results: The flow, working and setting times significantly decreased withincreasing particle concentration. The film thickness, dimensional change, water sorption and solubility values significantly increased with higher particle amount. The results for cytotoxicity showed no statistically significant differences among the particle proportions. Conclusions: The results suggest that the addition up to 80% wt of bismuth subsalicylate appears to be a promising filler particle to root canal sealer development

Influence of Different Thickness in the Degree of Conversion of an Adhesive Resin.

Objetivos: o objetivo desse trabalho foi avaliar o grau de conversão (GC) de diferentes espessuras (1; 2; 3 e 4 mm) de uma resina adesiva translúcida de uso odontológico. Materiais e métodos: o GC de uma resina adesiva translúcida foi avaliado por meio de espectroscopia no infravermelho por transformada de Fourier (FTIR) acoplado a um dispositivo de refletância total atenuada (ATR). Foram utilizadas quatro matrizes de polivinilsiloxano de 1; 2; 3 ou 4 mm de espessura por 7 mm de diâmetro cada uma para conter o adesivo dispensado (n = 3) sobre o cristal de diamante do dispositivo de ATR. ANOVA de uma via e teste de comparações múltiplas de Student-Newman-Keuls foram utilizados com um nível de significância estatística de 5%. Resultados: espécimes de 1 mm de espessura apresentaram estatisticamente maiores valores de GC (62,19± 0,20) comparado aos demais grupos (p0,05), mas foram maiores que o grupo de 4mm (p>0,05). Conclusão: é necessária a padronização da espessura dos espécimes submetidos ao ensaio de avaliação de GC por FTIR-ATR.Aim: the purpose of this study was to evaluate the degree of conversion (DC) of different thicknesses (1, 2, 3 and 4 mm) of a translucent dental adhesive resin Materials and Methods: the degree of conversion (DC) of adhesive resins was measured by Fourier Transform Infrared Spectroscopy (FTIR) equipped with an attenuated total reflectance device (ATR). It were used four matrices of polyvinylsiloxane with dimensions of 1; 2; 3 or 4 mm in thickness and 7 mm in diameter each one to contain the dispensed adhesive (n = 3) on the diamond crystal of the ATR device. The data were analyzed by one-way ANOVA and Student-Newman-Keels’ post hoc test (α=0.05). Results: specimens of 1 mm of thickness showed statistically higher DC (62.19 ± 0.20) compared to the other groups (p0.05), but groups of 2 and 3 mm showed higher DC than the group of 4 mm (

Resistência adesiva à microtração ao esmalte de um adesivo auto-condicionante simplifi cado: infl uência de múltiplas camadas

This study tested the null hypothesis that the number of applications of a self-etching primer would not infl uence the microtensile bond strength at the interface resin/enamel. Bovine teeth were fl atted to expose the prismatic enamel with wet 600 grit silicon carbide papers. The teeth were divided into two groups: FB 1coat, FuturaBond (Voco) applied according to the manufacturer’s instruction for 30 s; and, FB 4coats, applied four times, 30s each. Then, they were restored with Polofi l (Voco) resin composite. After 24h, samples were cut with a diamond low speed saw under water cooling to obtain stick-shaped specimens of approximately 0,5 mm2 cross-sectional area. The sticks underwent microtensile testing at a speed of 1 mm/min. The bond strength, in MPa, was: FB 1coat, 33.57 ±8.77 (18); FB 4coats: 33.57 ±8.77 (18). This values, at t student test, had not showed signifi cant difference (p=0.58). In this study, the number of coats did not interfere at the values of bond strength at the interface resin/enamel.Este estudo testou a hipótese nula de que o número de camadas de aplicação de um primer auto-condicionante pode não influenciar não resistência da interface adesiva resina/esmalte à microtração. Dentes bovinos foram niveladas, para expor os prismas de esmalte, utilizando-se lixa d´água #600. Os dentes foram divididos em dois grupos: FB 1 camada, FuturaBond (Voco) aplicado de acordo com as recomendações do fabricante por 30 s; e, FB 4 camadas, aplicadas quatro vezes, 30s cada. Foram então restaurados com a resina composta fotopolimerizável Polofil (Voco). Após 24 horas as amostras foram cortadas com um disco diamantado em baixa rotação sob abundante irrigação para obter palitos de aproximadamente 0,5 mm2 de área. Os palitos foram submetidos á microtração a uma velocidade de 1 mm/min. A resistência adesiva, em MPa, foi: FB 1 camada, 33.57 ±8.77 (18); FB 4 camadas: 33.57 ±8.77 (18). Esses valores, no teste t de student, não apresentaram diferença significativa (p=0.58). Nesse estudo, o número de camadas não interferiu nos valores de resistência de união da interface resina/esmalte

Mineral deposition promoted by resin-based sealants with different calcium phosphate additions.

The aim of this study was to evaluate the influence of different calcium phosphates (CaPs) on the physical, biological, and remineralizing properties of experimental resin-based sealants (RBSs). Triethylene-glycol dimethacrylate (90wt%) and bisphenol A-glycidyl methacrylate (10wt%) were used to produce resin-based sealants. Hydroxyapatite (SHAp), α-tricalcium phosphate (Sα-TCP) and octacalcium phosphate (SOCP) were added to the sealants in a 10wt% concentration. One group without CaPs was used as the control group (SCG). The degree of conversion (DC) was assessed with Fourier-transformed infrared spectroscopy, whereas cytotoxicity was tested with the HaCaT keratinocyte cell line. The ultimate tensile strength (UTS) was used to assess the mechanical strength of the experimental RBSs. Sealed enamel was used for colorimetric assay. Mineral deposition was assessed with Raman spectroscopy after 7, 14, and 28 days of sample immersion in artificial saliva. Scanning electron microscopy was used to analyze the surface morphology after 28 days of immersion. The addition of 10wt% of fillers significantly reduced the DC of sealants. SOCP groups showed reduced cell viability. Higher UTS was found for Sα-TCP and SHAp. The color analysis showed that SGC and demineralized teeth presented higher mismatches with the sound tissue. Mineral deposition was observed for SHAp and Sα-TCP after 7 days, with increased phosphate content and mineral deposits for SHAp after 28 days. RBS with the addition of 10% HAp promoted increased mineralization in vitro after 28 days, and did not affect cell viability, DC, mechanical properties, or RBS color in the enamel