title: Classification, reproducibility and prevalence of root proximity in periodontal patients.
abstract: OBJECTIVE
  The primary aim of this study is to define and classify root proximity. The secondary aim is to examine the reproducibility of the measurement tools, to study the prevalence per inter-dental area and to examine whether the distance from the cemento-enamel junction (CEJ) to the bone crest (BC) differs between sites with root proximity and their contra-lateral sites without root proximity.
  
  
  METHODS
  In order to indicate the location of root proximity, a modification of the Shei ruler was developed, dividing the roots into three equal parts. A radiographic template was used to measure the distance between the roots, in this way determining the severity of the root proximity. The reproducibility of the measurement tool was tested, the prevalence was calculated and the distances CEJ-BC for root proximity sites and contra-lateral sites were recorded.
  
  
  RESULTS
  A two-digit classification was obtained dividing the root into three locations [apical (A), between (B) and coronal (C)], with each location having the possibility of three different severities of root proximity. The described modification of the Shei ruler and the measurement tool for the severities can be considered as reproducible measurement tools. Root proximity was most prevalent in maxillary molars and between central and lateral incisors in the maxilla and mandible. There was no difference in CEJ-BC distance between the root proximity sites and their contra-lateral sites.
  
  
  CONCLUSIONS
  We can conclude that a two-digit classification for root proximity was established. Root proximity in untreated periodontal patients has no influence on the distance CEJ-BC. However, the location of root proximity becomes important from the moment that periodontal disease has been established at that site. The severity of root proximity is important for choosing treatment options. There is a striking similarity between bone loss patterns and tooth loss and the location of inter-dental spaces where root proximity is most prevalent.
authors.affiliation: Department of Periodontology and Biomaterials, Catholic University of Nijmegen, Nijmegen, The Netherlands. katrienvermylen@lycos.com
authors.forename: K
authors.initials: K
authors.lastname: Vermylen
authors.forename: G N Th
authors.initials: GN
authors.lastname: De Quincey
authors.forename: M A
authors.initials: MA
authors.lastname: van 't Hof
authors.forename: G N
authors.initials: GN
authors.lastname: Wolffe
authors.forename: H H
authors.initials: HH
authors.lastname: Renggli
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016301:Alveolar Bone Loss / Q000145:classification / Q000000981:diagnostic imaging; D000539:Alveolar Process / Q000000981:diagnostic imaging; D003238:Connective Tissue / Q000000981:diagnostic imaging; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007180:Incisor / Q000000981:diagnostic imaging; D008297:Male; D008334:Mandible; D008437:Maxilla; D008875:Middle Aged; D008963:Molar / Q000000981:diagnostic imaging; D009811:Odontometry / Q000295:instrumentation; D017622:Periodontal Attachment Loss / Q000145:classification / Q000000981:diagnostic imaging; D010510:Periodontal Diseases / Q000145:classification* / Q000000981:diagnostic imaging; D011859:Radiography; D015203:Reproducibility of Results; D019227:Tooth Apex / Q000000981:diagnostic imaging; D019237:Tooth Cervix / Q000000981:diagnostic imaging; D014092:Tooth Root / Q000000981:diagnostic imaging*