title: [Initial clinic research on curved canal preparation by reverse flaring technique].
abstract: OBJECTIVE
  Curved canal preparation is much difficult in root canal therapy(RCT). Step back technique and routine technique are still regular methods in curved canal preparation. The purpose of this study was to introduce a new method reverse flaring technique, and to investigate its preparation efficiency in intermediate-curvature canals.
  
  
  METHODS
  48 cases of lower first molars RCT were collected, which were first treated because of pulpitis or apical periodontitis in West China College of Stomatology, Sichuan University from Nov. 2001 to Aug. 2003, mesial canal curvature was intermediate (30 degrees-60 degrees), determined by Schineider method. Cases were divided into two groups, in reverse flaring technique group, canal preparation in 27 cases were finished by reverse flaring technique, 21 cases by step back technique as control. In working length determination and fitting master cone stages, cases in two groups which fit full working length were recorded, determined by radiograph, and analyzed by chi 2 test.
  
  
  RESULTS
  In working length determination stage, cases which fit full working length in reverse flaring technique group were significantly more than that of step back technique group (P < 0.05), in fitting master cone stage, cases which fit full working length in reverse flaring technique group were also significantly more than that of step back technique group(P < 0.05).
  
  
  CONCLUSIONS
  In working length determination stage, cases which fit full working length in reverse flaring technique group were significantly more than that of step back technique group (P < 0.05), in fitting master cone stage, cases which fit full working length in reverse flaring technique group were also significantly more than that of step back technique group(P < 0.05).
authors.affiliation: Dept. of Conservative Dentistry, West China College of Stomatology, Sichuan University, Chengdu 610041, China.
authors.forename: Jin-bo
authors.initials: JB
authors.lastname: Yang
authors.forename: Tian-jia
authors.initials: TJ
authors.lastname: Liu
authors.forename: Ji-yao
authors.initials: JY
authors.lastname: Li
mesh_terms: D000328:Adult; D003786:Dental Pulp Cavity / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008963:Molar; D010518:Periodontitis / Q000000981:diagnostic imaging / Q000628:therapy; D011671:Pulpitis / Q000000981:diagnostic imaging / Q000628:therapy*; D011859:Radiography; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods*; D012390:Root Canal Therapy; D019227:Tooth Apex / Q000033:anatomy & histology / Q000000981:diagnostic imaging