Capacidad de sellado de los conductos laterales con distintas técnicas de obturación del conducto radicular / Sealing capacity of lateral canals with different root canal obturation techniques

Objetivo: Estimar y comparar la eficacia de diferentes técnicas de obturación para impedir el flujo de colorante a través de los conductos laterales. Materiales y métodos: Se emplearon 50 premolares inferiores extraídos y conservados en formol neutro al 5% hasta el momento de su uso, a los cuales se les realizaron conductos laterales artificiales. Una vez instrumentados los conductos principales, los dientes fueron divididos al azar en 5 grupos (n=10) para ser obturados con cuatro técnicas distintas: A) System B + inyección de gutapercha termoplástica del sistema Elements, Extruder; B) obturadores de Thermafil, ProTaper Universal; C) técnica híbrida y D) obturación con inyección de gutapercha termoplástica del sistema Elements, Extruder. Inmersos en tinta china y diafanizadas las raíces, se evaluó la longitud de penetración de la tinta en los conductos laterales. Se empleó el análisis de la varianza para detectar diferencias significativas (P<0,05) entre los niveles medios de penetración del colorante según las técnicas de obturación y las zonas del diente, y se efectuaron pruebas de rango múltiple (HSD de Tukey) para realizar comparaciones dos a dos, manteniendo fija la tasa de error por familia. Resultados: A la técnica B le correspondió el valor medio más bajo (30,63%) de penetración de tinta china. Los valores medios más elevados (54,52% y 51,74%) correspondieron a las técnicas A y C, respectivamente. Conclusión: Ninguna de las técnicas de obturación del conducto radicular empleadas ha sido capaz de impedir la filtración del colorante en los conductos laterales (AU)

Aim: To estimate and compare the different obturation techniques to avoid the flow of colorant through lateral canals. Materials and methods: 50 extracted lower premolars preserved in 5% neutral formol until the moment of use, had artificial lateral canals made. Once canals were instrumented, the teeth were randomly divided into 5 groups (n=10) to be filled with four different techniques: A) System B + injection of thermoplastic gutta-percha, Elements system, Extruder; B) Thermafil, ProTaper Universal obturators; C) hybrid technique, and D) injection of thermoplastic gutta-percha, Elements system, Extruder. Having immersed the premolars in India ink and diaphanized the roots, the penetration length of the India ink inside the canals was assessed. Analysis of variance was used to detect significant differences (P<0.05) between the mean levels of dye penetration according to the filling techniques and tooth areas, and multiple range tests (Tukey's HSD) were performed for two-to-two comparisons, keeping the error rate per family fixed. Results: Technique B had the lowest mean value (30.63%) of penetration. The highest mean values (54.52% and 51.74%) corresponded to techniques A and C, respectively. Conclusion: No obturation technique of the root canal used was able to avoid filtration of colourant in the lateral canals (AU)

Antibacterial efficacy of HMME-PDT on Enterococcus faecalis within infected simulated lateral canals in vitro model with different energy / 国际生物医学工程杂志

Objective The purpose of this study was to assess the antibacterial effects of hematoporphyrin monomethylether-photodynamic therapy (HMME-PDT) on Enterococcus faecalis within infected simulated lateral canals in vitro with different energy.Methods Simulated lateral canals were prepared on extracted teeth.The specimens were infected with Enterococcus faecalis and then were randomly divided into eight groups.Group A was considered as negative control,its specimens were irrigated with physiological saline.Group B was the positive control,they were irrigated with 5.25％ NaClO.Other groups were incubated with HMME at concentration of 40 μg/ml for 5 min,followed by exposure to light at 532 nm for 120 s with different powers in a spiral pattern.Groups were named C-H,in corresponding with the power 50,60,70,80,90,100 mW.Microbial samples (the dentin chips from simulated lateral canals) were taken before and after the treatments.The survival fractions in each simulated lateral canal was calculated by counting colony-forming units(CFUs).Results 1.The HMME-PDT-treated groups resulted in a significant reduction in the number of E.faecalis in simulated lateral canals compared with the negative controls(P＜0.05).2.The antibacterial effects of group D、E、F、G、H were higher than the NaCl0-irrigated group(P＜0.05).3.The difference of antibacterial effects between the F、G、H groups was in significant(P＞0.05).Conclusion HMME-PDT had significant inhibitive efficacy on Enterococcus faecalis within infected simulated lateral canals and the efficacy was power-depended.It can play the best effect with the power of 80 mW.

Effectiveness of a silicon-based root canal sealer for filling of simulated lateral canals

The purpose of this in vitro study was to evaluate the ability of a silicon-based root canal sealer, compared to zinc oxide and eugenol and an epoxy resin-based sealers, for filling of simulated lateral canals. Thirty extracted single-rooted human teeth were selected, conventional access was made and the working length was established 1 mm from the apical foramen. Three simulated lateral canals, one in each root third (coronal, middle and apical) were prepared in both the mesial and distal surfaces of each tooth using a size 15 reamer adapted to a low-speed handpiece. Each root canal was instrumented using ProTaper rotary files up to file F3 at the working length, and then irrigated with 2.5 percent NaOCl followed by EDTA. The teeth were assigned to 3 groups (n=10), according to the root canal sealer: Roeko Seal (Group 1), Sealer 26 (group 2) and Grossman's sealer (Group 3). Gutta-percha cold lateral condensation technique was performed in all groups. Postoperative radiographs were taken and the images were projected for evaluation of the quality of lateral canal filling. Data were submitted to statistical analysis by Kruskal Wallis test at 5 percent significance level. The results showed that Grossman's sealer filled a larger number of lateral canals than Roeko Seal (p<0.05) and Sealer 26 (p<0.01). It may be concluded that Roeko Seal silicone-based root canal sealer was not as effective as the Grossman's sealer for filling of simulated lateral canals. The lateral canals localized in the apical third of the root were more difficult to be filled.

O objetivo desse estudo in vitro foi avaliar a capacidade de um cimento a base de silicone, em obturar canais laterais simulados, em comparação a um cimento à base de oxido de zinco e eugenol e um cimento resinoso. Trinta dentes humanos unirradiculares extraídos foram selecionados, a abertura coronária foi feita e o comprimento de trabalho foi determinado 1 mm aquém do forame apical. Foram confeccionados três canais laterais, um em cada terço radicular, em ambas as faces mesial e distal da raiz, usando um alargador 15 acoplado a um contra-ângulo em baixa rotação. Os canais foram instrumentados com sistema Protaper até a lima F3, sob irrigação com hipoclorito de sódio a 2,5 por cento, seguido de EDTA. Os dentes foram divididos em 3 grupos (n=10) e obturados com o cimento de Grossman, RoekoSeal ou Sealer 26, pela técnica da condensação lateral da gutta-percha. Foram feitas tomadas radiografias pós-operatórias, projetadas em aumentos de 20X para avaliação da qualidade das obturações. Os dados foram analisados estaticamente pelo teste de Kruskal Wallis com nível de significância de 5 por cento. Os resultados mostraram que o cimento de Grossman obturou um numero maior de canais laterais que o cimento RoekoSeal (p<0,05) e o Sealer 26 (p<0,01). Pode-se concluir que o cimento Roeko Seal não foi tão eficiente quanto o cimento de Grossman para o selamento de canais laterais, bem como, que os canais laterais situados no terço apical da raiz apresentaram maior dificuldade para serem obturados.