title: [Clinical evaluation of the effect of angulation apical X-rays and the X-rays with file in diagnosing multiple canals in mandibular anterior teeth and premolars].
abstract: OBJECTIVE
  To investigate different angle projection technique for the clinical detection and treatment of multiple canals in mandibular anterior teeth and premolars.
  
  
  METHODS
  Two hundred and forty-seven in vivo mandibular anterior teeth and premolars were selected from two hundred and fourteen patients. Four kinds of radiographs were taken for each tooth. The radiograph was taken at a horizontal angles of 0, 20 - 30 degrees from the mesial or distal of the tooth with and without files in canal. If a radiolucent line or files was present mesial or distal to the main canal, an additional canal was suspected. If the tooth appeared to have one large canal in the cervical or middle third of the root which disappeared or constricted as it traveled in an apical direction, an additional canal was suspected. The root canals were instrumented with ProTaper in crown-down mode and filled with laterally condensed gutta-percha and paste, the root canal configurations were classified into Types I - V.
  
  
  RESULTS
  60.92% multiple canals and 26.44% long oval canals were detected and treated from suspected multiple canals. The sensitivity of angle projection technique with file in X-ray diagnosing of multiple canals was 93.0%, and second canal was missed in four cases. The multiple canals in the 247 mandibular anterior teeth and premolars were present in central incisors: 9.43% (5 of 53); lateral incisors: 38.33% (23 of 60); canines: 15.90% (7 of 44), first premolar: 40.38% (21 of 52); second premolar: 2.63% (1 of 38).
  
  
  CONCLUSIONS
  The different angle projection technique will assist the clinician in the detection and treatment of multiple canals in mandibular anterior teeth and premolar, and angle projection technique with file detected more multiple canals.
authors.affiliation: Special Department, Peking University School and Hospital of Stomatology, Beijing 100081, China.
authors.forename: Bing-zhen
authors.initials: BZ
authors.lastname: He
authors.forename: Xing-zhe
authors.initials: XZ
authors.lastname: Yin
authors.forename: Cheng-fei
authors.initials: CF
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001641:Bicuspid / Q000000981:diagnostic imaging*; D003786:Dental Pulp Cavity / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007180:Incisor / Q000000981:diagnostic imaging*; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging; D008875:Middle Aged; D011859:Radiography; D012390:Root Canal Therapy