title: [A retrospective clinical analysis of endodontic treatment of maxillary first molars].
abstract: OBJECTIVE
  To evaluate the effect of root canal therapy (RCT) of maxillary first molars and the relevant influential factors.
  
  
  METHODS
  A total of 170 maxillary first molars undergoing endodontic treatment were retrospectively studied. 100 molars were treated with vertical compaction technique (VCT) using warm gutta- percha under dental operating microscope (DOM), while 70 molars with traditional lateral compaction technique (LCT) under naked eyes. All patients were asked to revisit 5 years later and 5-year success rate was evaluated. Reversion 3.0.2 software package was used to analyze the data.
  
  
  RESULTS
  The immediate high quality rates of RCT of VCT and LCT were 91% and 75.7%, respectively, which has significant difference (P<0.05). After 5 years, VCT kept high quality rate of RCT, while the high quality rate of RCT with LCT dropped from 75.7% to 68.6%. The 5-year clinical success rates of RCT with VCT and LCT were 98% and 81.4%, respectively; which had significant difference (P<0.05).
  
  
  CONCLUSIONS
  VCT has excellent clinical effect in RCT of maxillary first molars. The use of DOM can increase the detection rate of the second mesiobuccal canal (MB2).
authors.affiliation: Department of Stomatology, Beijing Shijitan Hospital. Beijing 100038, China. E-mail:zhangdh1966@sina.com.
authors.forename: De-hui
authors.initials: DH
authors.lastname: Zhang
authors.affiliation: Department of Stomatology, Beijing Shijitan Hospital. Beijing 100038, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Department of Stomatology, Beijing Shijitan Hospital. Beijing 100038, China.
authors.forename: Hai-tao
authors.initials: HT
authors.lastname: Sun
mesh_terms: D003786:Dental Pulp Cavity; D004708:Endodontics; D006171:Gutta-Percha; D006801:Humans; D008437:Maxilla; D008853:Microscopy; D008963:Molar; D012189:Retrospective Studies; D012390:Root Canal Therapy
chemical_list: D006171:Gutta-Percha