title: Prevalence of three-rooted mandibular permanent first molars among the Turkish population.
abstract: BACKGROUND
  This retrospective study was undertaken to determine the prevalence of three-rooted permanent mandibular first molars in digital periapical radiographic images obtained from a Turkish patient.
  
  
  METHODS
  Periapical radiographs of 640 subjects, which had been obtained in the Department of Oral Diagnosis Radiology, Kirikkale University Dental Faculty, Kirikkale, Turkey from June 2010 to March 2011, were screened and examined retrospectively. All radiographs were evaluated under optimal conditions using double magnifying glasses. Each radiograph was separately evaluated by two authors (H.Ç. and M.M.H.). Comparison of the incidence and the correlations between males and females and left- and right-side occurrences were analyzed by using the Pearson chi-square test with SPSS (15.0; SPSS Inc., Chicago, IL, USA).
  
  
  RESULTS
  The periapical radiographs of 9 patients, 4 females and 5 males, had three-rooted mandibular first molars. Of these three-rooted mandibular first molars, 7 were found on the right side and 5 on the left side. The overall incidence of patients with three-rooted mandibular first molars was 1.41%. The incidence was 1.63% for men and 1.2% for women.
  
  
  CONCLUSIONS
  The prevalence of three-rooted mandibular first molars from all teeth examined was 1% (12 of 1205), 1.17% (7 of 596) for the right side, and 0.82% (5 of 528) for the left side occurrences.
authors.affiliation: Department of Restorative Dentistry, Kirikkale University School of Dentistry, Kirikkale, Turkey. hakanclak@kku.edu.tr
authors.forename: H
authors.initials: H
authors.lastname: Colak
authors.forename: E
authors.initials: E
authors.lastname: Ozcan
authors.forename: M M
authors.initials: MM
authors.lastname: Hamidi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible; D008875:Middle Aged; D008963:Molar / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D009811:Odontometry / Q000379:methods; D011859:Radiography; D014092:Tooth Root / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D014421:Turkey; D044465:White People; D055815:Young Adult