Observation of the clinical effect between two kinds of NiTi rotary file in preparation molar curved root canals for the aged

Objective: To give the comparison the ability of the original root canal anatomy flow between two rotary files,which named Protaper and Hero 642,in preparation molar curved root canals for the aged.Methods: Selecting curved root canals(25° ~ 30°) cases to start root canal preparation according to Schneider measurement,in which 100 cases by Protaper while anther 100 cases by Hero 642 separately.For general analysis,all the cases are chosen from the newly diagnosed cases of patients about 60-70 years old in dental clinic last 2007.3 to 2010.3 randomly.Then,the evaluation of the root canal preparation and forming effect can be given after measuring root canals curvature of the dental film chip in final root canal file and the first root canal file.Results: Protaper success rate of 92%,failure rate of 8%,extent of apical transportation was 2.8 degrees.Hero 642 success rate of 99%,failure rate of 1%,extent of apical transportation was 1.6 degrees.The success rate of the latter has significant difference(P 0.05).Conclusion: ① Hero 642 NiTi rotary file has good forming capacity than the protaper NiTIi rotary file for elderly patients molar curved root canals.② combined two kinds of NiTIi rotary file,first Hero 642 extend through the root canal,then Protaper forming root canal,apical transportation can be reduced and the quality of root canal filling was improved.