Clinical feature and treatment of the second mesiobuccal canals of maxillary molars / 实用口腔医学杂志

Objective:To discuss the clinical feature and treatment of second mesiobuccal canal (MB2)of permanent maxillary molars. Methods:The root canals of 106 maxillary first molars and 80 maxillary second molars were explored with small size K files. The frequency and morphology of root canals were recorded. The canals of all cases were instrumented by Ni-Ti rotary instruments Hero 642, and obturated with lateral condensation technique. The efficiency of preparation and obturation was analyzed with radiographs before and after treatment. Results:The frequency of MB2 canal in maxillary first and second molars were 82.1% and 45.0%. Most MB2 was very fine and negotiated by size 8 or 10 file combined with EDTA. No transportation, ledge, or perforation was found except that one hand file was separated. Good result of treatment was achieved in most cases. Conclusion:The incidence of MB2 canals of maxillary first molars was higher than that of second molars, and most of them were very fine. The MB2 canals can be negotiated with small size file combined with EDTA, and shaped well with Ni-Ti rotary instruments.

Clinical management of moderately and severely curved canals with nickel-titanium rotary instrument / 实用口腔医学杂志

Objective:To evaluate the shaping ability of nickel-titanium (NiTi) rotary instrument Hero 642 combined with SX of ProTaper in moderately and severely curved root canals.Methods:42 teeth with moderately and severely curved canals in 42 patients were prepared by Hero 642 and SX of ProTaper using crown-down technique and obturated with lateral condensation method. The efficiency of the preparation and obturation were analyzed by radiographs before and after treatment. Results:After preparation by the rotary instrument the original curvature and alignment of the canals were kept. No transportation, apical blockage, ledge or perforation was found in all cases. In one case,the file was broken during operation.After treatment light pain was complained in 4 cases and the pain alleviated and disappeared spontaneously. Conclusion:The NiTi rotary instrumentation technique with Hero 642 and ProTaper can be used to prepare curved root canals effectively and quickly.