L. Vasiliadis

Effect of needle insertion depth and root canal curvature on irrigant extrusion ex vivo.

INTRODUCTION The aim of this study was to evaluate the effect of needle type and insertion depth, apical preparation size, and root canal curvature on irrigant extrusion by using a recently introduced method. METHODS Sixteen human teeth with a straight root canal (group A) and 16 with a moderately curved root canal (group B) were sequentially prepared to sizes 25 or 35, .06 taper and mounted on a plastic vial filled with distilled water to simulate a periapical lesion. The vial was either closed or open to the environment. A point-conductivity probe was used to determine the volume of extruded irrigant into the vial. NaOCl was delivered by an open-ended or a closed-ended needle at 1, 3, or 5 mm short of working length. Results were analyzed by two 4-way mixed-design analyses of variance. The level of significance was set to P < .05. RESULTS The open-ended needle extruded significantly more irrigant than the closed-ended. Irrigant extrusion decreased as needles moved away from working length or when the apical size was increased. Needle wedging increased extrusion, especially when an open-ended needle was used. Root canal curvature did not have a statistically significant effect on irrigant extrusion. CONCLUSIONS Needle type, needle insertion depth, and apical preparation size had a significant effect on irrigant extrusion.

A new method for real-time quantification of irrigant extrusion during root canal irrigation ex vivo

AIM (i) To introduce a new method of quantifying extruded irrigant during root canal irrigation ex vivo. (ii) to evaluate the effect of periapical tissue simulation and pressure equalization and (iii) to determine the effect of needle type, apical preparation size and apical constriction diameter on irrigant extrusion. METHODOLOGY Sixteen human single-rooted teeth were sequentially prepared to sizes 25-45, 0.06 taper and mounted on a plastic vial simulating a periapical lesion. The apical constriction diameter was standardized to 0.15-0.35 mm. The vial was filled with distilled water or air and was either open to the environment or closed. A point-conductivity probe was used to determine the volume of extruded irrigant into the vial. NaOCl was delivered by an open-ended or a closed-ended needle at 3 mm short of working length. Results were analysed by two 3-way repeated-measures ANOVAs. RESULTS The open-ended needle extruded significantly more irrigant than the closed-ended in the majority of cases (P < 0.002). An increase in the apical size was related to decreased irrigant extrusion (P < 0.024). The effect of constriction diameter was not significant. The water-closed and water-open methods were related to less extrusion than the air-closed and air-open methods, respectively (P < 0.005). Open systems (water-open, air-open) allowed extrusion of larger amounts of irrigant than corresponding closed systems (water-closed, air-closed) (P < 0.005). CONCLUSIONS The conductivity probe is a reliable method for real-time quantification of irrigant extrusion ex vivo. Not simulating tissue resistance in ex vivo experiments may lead to significant overestimation of irrigant extrusion.

Short‐ and long‐term sealing ability of Gutta‐flow and AH‐Plus using an ex vivo fluid transport model

AIM To use the fluid transport model to evaluate the ex vivo short- and long-term microleakage along root canals filled with Gutta-flow or AH-Plus using the cold lateral compaction technique. METHODOLOGY A total of 38 single-rooted human teeth were used for the assessment of microleakage. The crowns of the teeth were sectioned below their cemento-enamel junctions to adjust the length of the roots to approximately 15 mm. The root canals were instrumented using the step-back technique and filled using cold lateral condensation. The sealer employed was either Gutta-flow (Group A) or AH-Plus (Group B). Microleakage along the root canals was evaluated using a fluid transport model after periods of 1 week and 3 months. RESULTS The microleakage values (microL h(-1)) for group A were 0.36 +/- 0.33 at 1 week and 0.41 +/- 0.36 at 3 months. Group B showed mean microleakage values 0.2 +/- 0.31 at 1 week and 0.28 +/- 0.38 at 3 months. Statistical analysis indicated no significant differences (P > 0.05) between the two groups after either 1 week or 3 months. CONCLUSIONS There was no significant difference between AH-plus and Gutta-flow in terms of sealing ability.