Effect of diode laser irradiation on the apical sealing of MTA retrofillings.

Apical sealing is essential for the success of paraendodontic surgery, so any procedure that may favor an adequate sealing of the apical remainder should be performed. The purpose of this study was to evaluate the influence of diode laser irradiation on the apical sealing of root-end cavities with MTA retrofillings. Root canals in twenty extracted human teeth were shaped with K-files and filled with gutta-percha. The apexes were cut off and root-end preparations were performed. The roots were divided randomly in 2 groups. Group 1 (ten specimens) was retrofilled with MTA. Group 2 was irradiated with diode laser, with 1 W for 20 seconds, on the apical surface and root end cavity before retrofilling with MTA. The specimens had their external surfaces impermeabilized with cyanoacrylate, except for the apical surface, and were then immersed in 1% rhodamine B dye for 72 h and placed in plaster stone. After that, the specimens were submitted to longitudinal abrasion until half of the root remained. The linear dye leakage was observed in these mid-roots between the root canal wall and retrofilling. The linear dye leakage was measured with Image Lab software, and the results were statistically analyzed with Student's t test. There were no statistically significant differences between the two groups (p > 0.05). The diode laser irradiation did not improve the apical sealing of MTA retrofillings under the conditions of this in vitro study.

Effect of different dye solutions on the evaluation of the sealing ability of Mineral Trioxide Aggregate.

Alkaline materials have shown incompatibility with methylene blue dye in leakage experiments. The goal of the present study was to analyze the effect of different dyes on the evaluation of the apical sealing ability of Mineral Trioxide Aggregate root-end fillings. Fifty-six extracted human canines were submitted to root canal instrumentation and obturation. After apical resection, retrograde cavities were prepared and teeth were randomly divided into four experimental (n = 13) and two control groups (n = 2). The following root-end filling materials were used: groups 1 and 2--Pro Root MTA (Dentsply), groups 3 and 4--zinc oxide-eugenol cement (ZOE). Teeth in groups 1 and 3 were immersed in 2% methylene blue solution, while teeth in groups 2 and 4 were immersed in 0.2% rhodamine B in a reduced pressure environment for 48 hours. Teeth were then longitudinally sectioned and leakage was evaluated. Results were submitted to statistical analysis (ANOVA and Tukey's test). Group 1 presented the least leakage (p < 0.05). It was concluded that the evaluation of the sealing ability of MTA is influenced by the dye used, since this material presented better sealing ability when evaluated with Methylene Blue, but was similar to ZOE when evaluated with rhodamine B.

Effect of different dye solutions on the evaluation of the sealing ability of mineral trioxide aggregate

Tem sido demonstrada a incompatibilidade de materiais alcalinos com a solucão corante de azul de metileno utilizada em testes de infiltracão marginal. O objetivo do presente estudo foi analisar a influência de diferentes solucões corantes na avaliacão do selamento apical proporcionado pelo agregado de trióxido mineral. Cinqüenta e seis caninos humanos extraídos tiveram seus canais radiculares instrumentados e obturados. Após a seccão da porcão apical, cavidades retrógradas foram preparadas e os dentes divididos aleatoriamente em quatro grupos experimentais (n = 13) e dois controles (n = 2). Foram utilizados os seguintes materiais retrobturadores: grupos 1 e 2 - Pro Root MTA (Dentsply); grupos 3 e 4 - cimento de óxido de zinco e eugenol (OZE). Em seguida, os dentes dos grupos 1 e 3 foram imersos em solucão de Azul de Metileno a 2% e dos grupos 2 e 4 em solucão de Rodamina B a 0,2% por 48 horas em ambiente com vácuo. Decorrido este período, os dentes foram seccionados longitudinalmente, e a infiltracão marginal foi analisada. Os dados obtidos foram submetidos à análise estatística (Análise de variância e teste de Tukey). Os resultados demonstraram que o Grupo 1 apresentou menor infiltracão apical que os demais (p < 0,05). Conclui-se que a avaliacão da capacidade seladora do MTA é influenciada pela solucão corante, uma vez que o mesmo apresentou melhores resultados com o Azul de Metileno e infiltracão marginal semelhante à do OZE quando avaliado em solucão de Rodamina B.

Sealing ability of MTA, Super EBA, Vitremer and amalgam as root-end filling materials

Este estudo avaliou a capacidade de selamento do agregado trióxido mineral (MTA Angelus), de um cimento de óxido de zinco e eugenol reforçado (Super EBA), de um cimento de ionômero de vidro reforçado por resina (Vitremer) e de um amálgama sem zinco (GS-80) (controle). Os canais radiculares de oitenta molares inferiores humanos foram acessados, limpos, modelados e obturados. Os ápices foram seccionados, e as cavidades, preparadas. Os dentes foram divididos em 4 grupos de 40 cavidades, retrobturados com os materiais e imersos em azul de metileno por 72 h a 37ºC. As raízes foram então seccionadas transversalmente a cada milímetro e avaliadas sob aumento, observando-se a penetração de corante a cada corte. Os dados foram avaliados usando-se o teste de Kruskal-Wallis (5%), que mostrou diferenças entre todos os materiais (p < 0,001). A ordem crescente de infiltração marginal foi MTA < Vitremer < Super EBA < amálgama. Níveis mais altos de infiltração foram observados nos cortes de primeiro milímetro de amálgama, Vitremer e MTA, quando comparados com o terceiro milímetro (p < 0,05).