Resistência à fratura de dentes tratados endodonticamente reforçados com pinos customizados de fibra de vidro e carbono / Fracture resistance of endodontically treated teeth reinforced with customized glass and carbon fiber posts

Objetivo: o objetivo do presente estudo foi comparar a resistência à fratura de quatro tipos de pinos intrarradiculares pré-fabricados: fibra de vidro, fibra de vidro customizado com resina composta, fibra de carbono e fibra de carbono customizado com resina, em dentes bovinos. Métodos: foram utilizados 60 dentes bovinos unirradiculares, que receberam tratamento endodôntico e foram divididos nos seguintes grupos: FV = pino de fibra de vidro; FVP = pino de fibra de vidro customizado; FC = pino de fibra de carbono; FCP = pino de fibra de carbono customizado; e Controle = restauração coronária com resina composta. Os dentes foram inseridos em blocos de resina acrílica, a 2 mm da junção amelocementária, simulando a interface dente-osso. Os espécimes foram submetidos ao teste de resistência à fratura em máquina de ensaio universal, sob uma carga de 0,5mm/min, até a fratura do corpo de prova. Os valores obtidos foram submetidos ao teste ANOVA, com pós-teste de Tukey. Foi realizada, também, uma análise dos padrões de fratura, por meio do teste Kruskal- -Wallis. Resultados: o grupo FCP mostrou os maiores valores de resistência à fratura, seguido pelos grupos FV, FVP e FC. O grupo controle mostrou menor resistência do que os demais, que receberam pinos intrarradiculares. Os pinos de FVP apresentaram o maior número de fraturas reparáveis, em contraste ao controle, no qual houve o maior número de fraturas desfavoráveis. Conclusão: o uso de pinos customizados reduziu a incidência de fraturas catastróficas. A ausência de pino intrarradicular ocasionou a maior incidência de fraturas irreparáveis. (AU)

Objective: The aim of this study was to compare the fracture resistance of four types of prefabricated intraradicular posts - glass fiber, glass fiber customized by composite resin, carbon fiber, and customized carbon fiber - on bovine teeth. Methods: Sixty bovine teeth were submitted to endodontic treatment and divided into the following groups: GF - glass fiber post; CGF - customized glass fiber post; CF - carbon fiber post; CCF - customized carbon fiber post; control - composite resin restoration. The teeth were embedded in acrylic resin blocks at 2 mm from the cement-enamel junction, simulating the teeth-bone interface. The specimens were submitted to a fracture resistance test in a universal test machine under a 0.5 mm/min load until the fracture of the specimen. The values obtained were submitted to ANOVA and Tukey tests. The analysis of the fracture patterns was performed by the Kruskal-Wallis test. Results: The CCF group presented the highest values of fracture resistance, followed by GF, CGF, and CF posts. The control group offered less resistance than the other groups that received intraradicular posts. The CGF presented the highest number of favorable fractures, in contrast to the control group, which presented the highest number of unfavorable fractures. Conclusion: The use of customized posts reduced the incidence of catastrophic fractures. The lack of intracanal posts led to a higher incidence of irreparable fractures (AU).

Influência do comprimento de trabalho na extrusão de detritos e hipoclorito de sódio / Influence of working length on apical extrusion of debris and sodium hypochlorite

Objetivo: o objetivo deste estudo foi avaliar a quantidade de detritos e hipoclorito de sódio extruídos apicalmente quando três diferentes comprimentos de trabalho foram utilizados para o preparo do canal. Métodos: utilizou-se trinta dentes unirradiculares, e o sistema rotatório ProTaper foi usado para o preparo do canal radicular. Os dentes foram divididos aleatoriamente em três grupos experimentais (n = 10): G1) instrumentação 1 mm aquém do forame principal; G2) instrumentação no limite do forame apical; e G3) instrumentação 1 mm além do forame. Todos os grupos foram irrigados com 20 ml de hipoclorito de sódio a 1%. O irrigante extruído através do forame apical durante preparo do canal foi coletado em tubos Eppendorf pré-pesados. Resultados: os dados foram analisados utilizando testes de Kruskal-Wallis e Dunn. O G1 apresentou a menor quantidade de hipoclorito de sódio extruído, significativamente diferente dos demais grupos (p < 0,05). Conclusões: o comprimento de trabalho para a instrumentação do canal radicular tem influência direta na quantidade de hipoclorito de sódio extruído apicalmente. (AU)

Evaluation of the efficacy of filling material removal and re-filling after different retreatment procedures.

This study analyzed the influence of different retreatment protocols on amount of remaining filling material and amount of new sealer after endodontic retreatment. Forty mandibular molars with curved mesial roots were prepared with ProTaper Universal system, and filled with AH Plus sealer mixed with 0.1% rhodamine B and gutta-percha. After 7 days, the specimens were randomized according to the retreatment protocol (n = 10): ProTaper Retreatment System (PTR); PTR+Orange Oil (PTR+OO); PTR+Passive Ultrasonic Irrigation (PTR+PUI). No retreatment was performed in the control group (CG). After retreatment, the root canals were filled with AH Plus mixed with 0.1% fluorescein and gutta-percha. Samples were evaluated under confocal laser scanning microscopy and analyzed using Image J software. Data were analyzed using Kruskal-Wallis and Dunn tests (p < 0.05). Regarding presence of residual filling, the Kruskal-Wallis test indicated no differences among the different retreatment techniques in the perimeter and the isthmus analyses (p > 0.05); however, PTR+PUI was associated with a lesser amount of residual filling material in the canal area analysis (p < 0.05). In evaluating the new filling, the perimeter analysis showed a lesser amount of new endodontic sealer in the PTR group (p < 0.05). Moreover, the PTR+PUI group presented a significantly greater amount of new endodontic sealer in the canal area analysis (p < 0.05). There was no difference among groups in the isthmus analysis (p > 0.05). It can be concluded that PTR associated to PUI yielded better results in removing root canal filling material from the canal area. However, none of the protocols resulted in root walls completely free of remnants.

Evaluation of the efficacy of filling material removal and re-filling after different retreatment procedures

Abstract This study analyzed the influence of different retreatment protocols on amount of remaining filling material and amount of new sealer after endodontic retreatment. Forty mandibular molars with curved mesial roots were prepared with ProTaper Universal system, and filled with AH Plus sealer mixed with 0.1% rhodamine B and gutta-percha. After 7 days, the specimens were randomized according to the retreatment protocol (n = 10): ProTaper Retreatment System (PTR); PTR+Orange Oil (PTR+OO); PTR+Passive Ultrasonic Irrigation (PTR+PUI). No retreatment was performed in the control group (CG). After retreatment, the root canals were filled with AH Plus mixed with 0.1% fluorescein and gutta-percha. Samples were evaluated under confocal laser scanning microscopy and analyzed using Image J software. Data were analyzed using Kruskal-Wallis and Dunn tests (p < 0.05). Regarding presence of residual filling, the Kruskal-Wallis test indicated no differences among the different retreatment techniques in the perimeter and the isthmus analyses (p > 0.05); however, PTR+PUI was associated with a lesser amount of residual filling material in the canal area analysis (p < 0.05). In evaluating the new filling, the perimeter analysis showed a lesser amount of new endodontic sealer in the PTR group (p < 0.05). Moreover, the PTR+PUI group presented a significantly greater amount of new endodontic sealer in the canal area analysis (p < 0.05). There was no difference among groups in the isthmus analysis (p > 0.05). It can be concluded that PTR associated to PUI yielded better results in removing root canal filling material from the canal area. However, none of the protocols resulted in root walls completely free of remnants.