Effect of Movement Kinematics and Heat-Treated Alloys on the Apical Extrusion of Debris: An In Vitro Study.

BACKGROUND: Apically extruded debris can be affected by some features of the file systems such as kinematics or metallurgic properties. AIMS: This in vitro study aimed to evaluate the effect of movement kinematics (reciprocation or rotation) and heat-treated alloys (C.Wire) on the amount of debris extrusion. METHODS: Seventy-two mesiobuccal root canals were assigned into three experimental groups related to the single-file system used (n = 24): two rotational; One Shape (Conventional Ni-Ti), One Curve (C.Wire), and one reciprocating; and One Reci (C.Wire). The file systems were used according to the advisable speed and torque according to the manufacturers' suggestion. The weight of debris was calculated by subtracting the preweights from postweights of Eppendorf tubes. Kruskall-Wallis and Mann-Whitney U tests were used to analyze the data (P = 0.05). RESULTS: One Shape produced the greatest amount of extruded debris compared with One Curve (P < 0.001) and One Reci (P < 0.001), respectively. No statistical difference was found between One Curve and One Reci concerning amount of apical debris extrusion (P = 0.489). CONCLUSION: Metallurgical properties of files may affect apical debris extrusion. Alloy type is an important factor in the amount of debris extrusion. File kinematics does not affect apical debris extrusion.

Evaluation of the amount of apically extruded debris during retreatment of root canals filled by different obturation techniques.

OBJECTIVE: To evaluate the amount of apically extruded debris during retreatment (with or without solvent) of root canals filled by two obturation techniques. MATERIALS AND METHODS: Forty-eight root canals were prepared using ProTaper Universal F3 and filled with Gutta-percha and AH 26 sealer using single cone or lateral condensation techniques. The root canal fillings were removed using ProTaper Universal Retreatment system with or without solvent, and the canals were further prepared with ProTaper F4. The operating time was measured. The debris extruded was collected into preweighed Eppendorf tubes. The dry weight of the extruded debris was calculated by subtracting the weight of the empty tube from that of the tube containing debris. Statistical analysis was performed with two-way analysis of variance test, with Bonferroni correction at a 95% confidence level. RESULTS: There was no statistically significant difference in the amount of extruded debris between the two obturation techniques (P=0.332). The mean amount of debris was higher in the nonsolvent groups than the solvent groups, particularly with the single cone technique (P=0.013). There was a significant difference between groups with regard to the retreatment time (P<0.001). Gutta-percha removal took less time in the single cone group than in the lateral condensation group (P<0.001). Gutta-percha removal in the nonsolvent groups took significantly less time than that in the solvent groups (P<0.001). CONCLUSIONS: The amounts of apically extruded debris were similar in both obturation techniques. A greater amount of apically extruded debris was observed in the nonsolvent groups than the solvent groups.