title: Comparison of fracture sites and post lengths in longitudinal root fractures.
abstract: BACKGROUND
  Comparing the epidemiology of fractures originating in the cervical and apical regions may help to understand the causes and risk of a vertical root fracture. We aimed to determine the frequency of vertical root fractures in different fracture sites and how the fracture site relates to fracture direction and post length.
  
  
  METHODS
  Teeth diagnosed with a vertical root fracture were retrospectively surveyed for age and sex of the patient, type of tooth, a fracture region in the longitudinal axial direction, site of the fracture, and presence of a post. The fracture region in the longitudinal axial direction was classified as an incomplete fracture, complete fracture, and uncertain. Incomplete fractures were further classified into a fracture originating in the cervical region, a fracture originating in the midregion, and a fracture originating in the apical region. Posts were evaluated by loss of post and length of post.
  
  
  RESULTS
  Fractures originating in the cervical and apical region occurred around the same frequency, whereas fractures originating in the midregion were extremely scarce. Of the fractures originating in the cervical region, 36.2% were in a mesial and/or distal site and 57.4% in a buccal and/or lingual site. Of the fractures originating in the apical region, 90.8% were in the buccal and/or lingual site. The number of cases of fractures originating in the apical region decreased with increased post length.
  
  
  CONCLUSIONS
  Sites of fracture and post length differed greatly between fractures originating in the cervical region and the apical region, suggesting that risk factors for fractures originating in the cervical and apical regions are different.
authors.affiliation: Department of Periodontology and Endodontology, Hokkaido University Graduate School of Dental Medicine, Hokkaido, Japan. Electronic address: sugaya@den.hokudai.ac.jp.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Sugaya
authors.affiliation: Department of Periodontology and Endodontology, Hokkaido University Graduate School of Dental Medicine, Hokkaido, Japan.
authors.forename: Megumi
authors.initials: M
authors.lastname: Nakatsuka
authors.affiliation: Department of Periodontology and Endodontology, Hokkaido University Graduate School of Dental Medicine, Hokkaido, Japan.
authors.forename: Kana
authors.initials: K
authors.lastname: Inoue
authors.affiliation: Department of Periodontology and Endodontology, Hokkaido University Graduate School of Dental Medicine, Hokkaido, Japan.
authors.forename: Saori
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Department of Periodontology and Endodontology, Hokkaido University Graduate School of Dental Medicine, Hokkaido, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Miyaji
authors.affiliation: Department of Periodontology, Fukuoka Dental College, Fukuoka, Japan.
authors.forename: Ryuji
authors.initials: R
authors.lastname: Sakagami
authors.affiliation: Department of Periodontology and Endodontology, Hokkaido University Graduate School of Dental Medicine, Hokkaido, Japan.
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Kawamami
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003799:Dental Stress Analysis; D005260:Female; D006801:Humans; D007180:Incisor / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011176:Post and Core Technique; D012189:Retrospective Studies; D018915:Root Canal Preparation / Q000379:methods; D014082:Tooth Fractures / Q000503:physiopathology*; D014092:Tooth Root / Q000503:physiopathology*
keywords: Fractures originating in the apical region; fractures originating in the cervical region; post length; site of fracture; vertical root fracture