title: Root proximity as a risk marker for periodontal disease: a case-control study.
abstract: OBJECTIVE
  The aim of this study is first, to examine the prevalence, symmetry and spread of root proximity using the measurement tools and classification as described in part I of the study, and second to examine whether root proximity is a risk marker for periodontal disease.
  
  
  METHODS
  The radiographs of 227 patients were examined. The study consisted of a study group of 197 patients with advanced periodontal disease with at least one site with bone loss more than one third of the root length and 30 controls without periodontal disease. Every inter-proximal space was assessed on the full-mouth radiographs and a score was assigned according to severity and location. Consequently prevalence of severity and location, symmetry, spread and an odds ratio and relative risk for periodontal disease was calculated.
  
  
  RESULTS
  Root proximity is a symmetrical and localized but widespread phenomenon in periodontal patients and to lesser extend in the non-periodontal control group. In periodontal patients root proximity was most often encountered in the coronal and intervening part whereas subjects without periodontal disease had more root proximity in the apical and intervening part where it is less critical. Subjects with bilateral root proximity had a 3.6 times higher chance to have periodontitis.
  
  
  CONCLUSIONS
  Root proximity must be taken into consideration as a risk marker for periodontal disease.
authors.affiliation: Department of Periodontology and Biomaterials, Catholic University of 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: G N
authors.initials: GN
authors.lastname: Wolffe
authors.forename: M A
authors.initials: MA
authors.lastname: van 't Hof
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; D001641:Bicuspid / Q000000981:diagnostic imaging; D016022:Case-Control Studies; D003481:Cuspid / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D007180:Incisor / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D008963:Molar / Q000000981:diagnostic imaging; D009811:Odontometry / Q000295:instrumentation; D010510:Periodontal Diseases / Q000145:classification* / Q000000981:diagnostic imaging; D010518:Periodontitis / Q000145:classification / Q000000981:diagnostic imaging; D011859:Radiography; D018570:Risk Assessment; D019227:Tooth Apex / Q000000981:diagnostic imaging; D019237:Tooth Cervix / Q000000981:diagnostic imaging; D014092:Tooth Root / Q000000981:diagnostic imaging*