Ensayo aleatorizado in vitro sobre la capacidad de obturación de sistemas con vástago en conductos curvos / In vitro randomized-trial on the sealing ability of carrier-based systems in curved root canals

Objetivo: Comparar el porcentaje de área de gutapercha, cemento y huecos en conductos curvos obturados con sistemas con vástago y evaluar la influencia de la activación del cemento durante su colocación. Metodología: 120 conductos curvos de molares mandibulares fueron preparados a un diámetro apical ProFile 30, 0.04. Se obturaron con los sistemas GuttaCore, GuttaFusion o condensación lateral y AHplus (n = 40). Se subdividieron los grupos (n = 20) y se colocó el cemento con activación sónica o no. El cemento se mezcló con Rodamina B para permitir el análisis mediante microscopía confocal. Se calculó el área de gutapercha, cemento y huecos a 3, 6 y 9 mm del ápice. Se realizó el análisis estadístico utilizando ANOVA de dos vías. Para la comparación por pares se realizó el test de Sidak. Resultados: Cuando se comparan los sistemas de gutapercha a 3 mm, GF mostró un mejor comportamiento. CL obtuvo los peores resultados. No se encontró influencia entre los sistemas de obturación y la activación del cemento. Cuando se comparó el porcentaje de huecos entre todos los grupos, los perores resultados fueron para CL a 6 y 9 mm. Conclusiones: Bajo las condiciones de este estudio, el área de gutepercha, cemento y huecos depende del sistema de obturación utilizado. El uso de activación del cemento no influye en la calidad de la obturación

Aim: To compare the percentage of gutta-percha, sealer and voids in curved root canals filled with different gutta-percha carrier-based systems and to assess the influence of activation of the cement during its placement. Methodology: 120 curved canals of mandibular molars were prepared to an apical size ProFile 30, 0.04. They were filled with either GuttaCore, GuttaFusion or lateral condensation and AHplus (n=40). Groups were subdivided (n=20) and sonic activation or not during the placement of the cement was carried out. Cements were labelled with Rhodamine-B dye to allow analysis under confocal microscopy. Percentage of gutta-percha, sealer and voids area were calculated at 3, 6 and 9 mm from the apex. Statistical analysis was performed using two-way ANOVA test. To compare between the obturation systems Sidak correction for multiple comparisons was applied. Results: When comparing the gutta-percha systems at the 3 mm level, GF revealed a better performance. At 6 and 9mm, LC obtained the worst results. An influence between the obturation systems and the activation of the cement was not found. When comparing the percentage of voids among all the groups, worst results were found for LC at 6 and 9 mm. Conclusions: Under the conditions of this study, gutta-percha, sealer area and voids were dependent on the obturation system. The use of activation of the cement do not influence the quality of root filling

Estudio in vivo sobre la precisión de los localizadores de ápice iPex y Root ZX en la determinación de la longitud de trabajo / Evaluation of the accuracy of iPex and Root ZX apex locators determining the working length

Propósito: El propósito de este estudio in vivo es evaluar la precisión de los localizadores de ápice iPex y Root ZX en la determinación de la longitud del conducto. Materiales y Métodos: Se seleccionaron 34 dientes monorradiculares indicados para extracción. Se efectuaron las mediciones electrónicas (ME) con iPex y Root ZX tras la irrigación del conducto con EDTA al 17%. Después de la extracción del diente, se determinó la longitud real (LR) del conducto a 0,5 mm del foramen mayor. Las mediciones electrónicas de cada diente se compararon con la LR mediante, analizándose las diferencias con el test estadístico de análisis de la varianza. Resultados: Se identificaron diferencias estadísticamente significativas entre la LR y ME de Ipex (p = 0,02) y entre ME de Ipex y ME de Root ZX (p = 0,02). No se observaron diferencias estadísticamente significativas entre LR y la ME de Root ZX (p = 0,66). La media de la distancia desde la punta de la lima hasta la LR fue de -0,09 ± 1,06 mm para el Root ZX y de -0,52 ± 1,19 mm para el iPex (p < 0,05). Conclusiones: El Root ZX posee mayor precisión en determinar la longitud del conducto que el Ipex

Purpose: This in vivo study aims to evaluate the accuracy of iPex and Root ZX electronic apex locators in the determination of the oot canal working length. Materials and methods: 34 extracted one-rooted teeth were selected. Electronic measurements (EM) were made with iPex and Root ZX after irrigation of the root canal with EDTA to 17%. After the tooth extraction, real working length (RWL) was determined 0.5 mm from the greater foramen. EM of each tooth was compared with the RWL by analyzing differences in the statistical analysis of variance test. Results: statistically significant differences was identified between RWL and EM with Ipex (p = 0.02) and between EM with Ipex and Root ZX (p = 0.02). No statistically significant differences were observed between RWL and EM with Root ZX (p = 0, 66). The average distance from the tip of the file to the RWL was - 0.09 ± 1.06 mm for Root ZX and -0.52 ± 1.19 mm for iPex (p < 0.05). Conclusions: Root ZX had more accuracy than iPex in the determination of the root canal working length

Failure of ProTaper rotary Ni-Ti instruments used by undergraduate students.

OBJECTIVE: To evaluate the effect of number of uses, angle and radius of curvature and type of instrument on the fracture of ProTaper rotary instruments when used by undergraduate students. STUDY DESIGN: Three hundred and seventy-six molars, with a total of 1114 root canals, extracted were instrumented by undergraduate students using ProTaper instruments according to the manufacturer´s recommendations. When fracture occurred, data were collected concerning the number of uses, type of instrument, level of fracture, angle and radius of curvature. ANOVA test were used to determine the influence of type of instrument in the incidence of instrument fracture. Logistic regression model was used to determine the influence of number of uses, angle and radius of curvature in the incidence of instrument fracture. Significance was set at p< 0.05. RESULTS: A total of 37 Ni-Ti rotary instruments fractured during the treatment. Fracture occurred in 9.84% (37/376) of the teeth treated and 3.32% of the canals prepared with Ni-Ti rotary instruments (37/1114). A decrease in the radius of curvature of the canal significantly increased the likelihood of fracture (p=0.0001). Instrument fracture significantly increased as the number of uses increased (p=0.0037). No significant differences were found between the 6 types of ProTaper instruments (p=0.8). A reduction in the angle of curvature did not produce a significant decrease in the incidence of instrument separation (p=0.08). CONCLUSIONS: The results of this study imply that instrument fracture is linked to radius of curvature and number of uses. Key words:Fracture, ProTaper ®, root canal preparation, undergraduate students.