Micro-push-out bond strength of mineral­based root canal sealer in canals with different tapers / Fuerza de unión por micro-expulsión del sellador de conductos radiculares a base de minerales en conductos con diferentes ahusamientos

Objective: The aim of this study was to assess the micro-push-out bond strength of a mineral-based root canal sealer, BioRoot RCS in canals prepared by K3XF rotary systems of two different tapers. Material and Methods: Eighty caries free maxillary central incisors were used in this study. The samples were allocated into 4 groups (n=20) according to the root canal sealer and taper of the rotary instruments. The samples were obturated using single cone obturation technique. From each root 1mm thick slices at coronal, middle and apical thirds were collected using hard tissue microtome under continuous water coolant. Push-out tests were done for these sections using a Universal testing machine (INSTRON 8801) at a crosshead speed of 1mm/min. One-way analysis of variance (ANOVA) was used to compare the bond strengths within groups and Tukey's multiple post hoc analysis was used for pair-wise comparison of bond strengths. Results: AH Plus exhibited higher micro-push-out bond strength than BioRootRCS though they did not differ significantly (p>0.05). Preparation of root canals with 6% taper rotary instruments showed higher bond strength than 4% though they did not differ significantly (p>0.05). Conclusion: There was no significant difference between micro-push-out bond strength values of BioRoot RCS and AH Plus. The bond strength values were high in 6% taper canals than 4% canals though the difference was not significant statistically.

Objetivo: El objetivo de este estudio fue evaluar la fuerza de unión por micro-expulsión de un sellador de conductos radiculares de base mineral, BioRoot RCS, en conductos preparados por sistemas rotativos K3XF con dos conos diferentes. Material y Métodos: En este estudio se utilizaron 80 incisivos centrales superiores libres de caries. Las muestras se distribuyeron en cuatro grupos (n = 20) de acuerdo al sellador del conducto radicular y al cono de los instrumentos rotativos. Las muestras se obturaron mediante la técnica de obturación de un solo cono. De cada raíz se recogieron rodajas de 1 mm de grosor en los tercios coronal, medio y apical utilizando un micrótomo de tejido duro con refrigeración continua por agua. Posteriormente, se realizó una prueba de expulsión para estas secciones utilizando una máquina de prueba universal (INSTRON 8801) a una velocidad del cabezal transversal de 1mm/min. Se utilizó el análisis de varianza unidireccional (ANOVA) para comparar las resistencias de la unión dentro de los grupos y el análisis post hoc multiple de Tukey se utilizó para la comparación por pares de las resistencias de la unión. Resultados: AH Plus exhibió una fuerza de unión de micro-expulsión más alta que BioRootRCS, aunque no difirieron significativamente (p>0,05). La preparación de los conductos radiculares con instrumentos rotativos ahusados al 6% mostró una fuerza de unión superior al 4%, aunque no difirieron significativamente (p>0,05). Conclusión: No hubo diferencias significativas entre los valores de fuerza de unión de micro-expulsión de BioRoot RCS y AH Plus. Los valores de la fuerza de unión fueron más altos en canales cónicos al 6% que en canales al 4%, aunque la diferencia no fue significativa estadísticamente.

Effectiveness of different final irrigation techniques and placement of endodontic sealer into dentinal tubules

Abstract: The aim of this study was to compare two irrigation techniques and four devices for endodontic sealer placement into the dentinal tubules. Ninety-nine single-rooted human teeth were instrumented and allocated to either the control (CO) (n=11) or experimental groups according to the irrigation method: syringe and NaveTip needle (NT) (n=44), and EndoActivator (EA) (n=44). These groups were subdivided according to sealer placement into K-File (KF), lentulo spiral (LS), Easy Clean (EC), and EndoActivator (EA) subgroups. Moreover, the distances of 5 mm and 2 mm from the apex were analyzed. The teeth were obturated with AH Plus and GuttaCore X3. Analyses were performed by scanning electron microscopy associated to cathodoluminescence. The percentage and maximum depth of sealer penetration were measured. Data were evaluated by three-way analysis of variance (ANOVA) and Games-Howell test (p<0.05). EA was superior to NT in percentage of sealer penetration. EC was significantly superior to EA (subgroup) for sealer penetration, and both improved the percentage of sealer penetration when compared to LS. Better sealer penetration was observed at the distance of 5 mm from the apex. Sealer penetration into the dentinal tubules was significantly improved by sonic irrigant activation.