关键词: 弯曲根管；封闭性能；预备方法；O-TB法

Abstract:

Objective     To evaluate the sealing ability of curved root canals prepared by different preparation methods. Methods     Sixty curved human maxillary anterior and premolar teeth were divided randomly into four experimental groups (A,B,C,D; 12 teeth per group）and two control groups(E,F; 6 teeth per group). The experimental groups were prepared by using the balanced force technique(A), the ProTaper/crown-down technique(B), the step-down technique(C), the step-back technique(D) and obturated by cold laterally compacted gutta-percha with Cortisomol sealer. Control groups included six positive and six negative subjects. Leakage along the root filling was measured by concentration of glucose in the apical reservoir on the thirtieth days with the O-TB method. Results     Leakage was outstanding in the positive controls but could not be detected in the negative controls. Mean concentrations of glucose of the four experimental groups were (4.22±0.53), (4.51±0.70), (4.86±1.30) and (7.62±1.35)mmol/L, respectively. There was significant difference between the step-back technique and the other three preparation methods (P＜0.05). No difference among the balanced force technique group, the ProTaper/crown-down technique and step-down technique group was observed (P＞0.05). Conclusion     The sealing ability of the balanced force technique, the ProTaper/crown-down technique and the step-down technique is better than that of  the step-back technique in curved teeth in vitro.

Key words: Curved root canals; Sealing ability; Preparation technique; O-TB method