title: Radiographic study of the prevalence of periodontal bone loss in Australian school-aged children attending the Royal Dental Hospital of Melbourne.
abstract: OBJECTIVE
  To investigate the prevalence of alveolar bone loss around the first permanent molars, and first and second deciduous molars in Australian school-aged children attending the Royal Dental Hospital of Melbourne.
  
  
  METHODS
  Nine hundred and ninety-five records were examined for useable bitewing radiographs. From these, radiographs of 542 Australian school children aged 5-12 years were used. The cervical-enamel junction (CEJ) to the alveolar bone crest (ABC) distance was measured using the transparent ruler on the magnifier. Each inter-dental site that was readable was scored as one for the following categories: not available (NA); no bone loss (NBL)- the CEJ-ABC was < or =2 mm; questionable bone loss (QBL): the distance from the CEJ-ABC was >2 and <3 mm; and definite bone loss (DBL): the distance from the CEJ to ABC was > or =3 mm.
  
  
  RESULTS
  Seventy-one children (13.0%) were found to have 83 DBL sites, as determined by bone levels >3.0 mm from the CEJ. Seventy children had QBL lesions only, 50 children had DBL only and 21 children had both. The overall prevalence of bone loss was 26%. Second deciduous molars were found to be the most affected teeth with almost 75% lesions being distal. These teeth comprised 50% of the DBL lesions. Children of Asian-Far Eastern origin had a higher percentage of sites with bone loss compared with children of Caucasian origin, being 29.5% and 19.7%, respectively, but lower than that of children of Middle-Eastern origin (35.2%). When the data were analysed with relation to age, there was no relationship between age and prevalence of bone loss.
  
  
  CONCLUSIONS
  In the population studied, there was an overall prevalence of periodontal bone loss of 26% and DBL of 13% in an Australian school-aged group. Calculus was detected infrequently and, where present, was associated with bone loss.
authors.affiliation: Periodontics, School of Dental Science, University of Melbourne, Melbourne, Vic., Australia. idarby@unimelb.edu.au
authors.forename: Ivan B
authors.initials: IB
authors.lastname: Darby
authors.forename: Janet
authors.initials: J
authors.lastname: Lu
authors.forename: Hanny
authors.initials: H
authors.lastname: Calache
mesh_terms: D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000208:ethnology; D000539:Alveolar Process / Q000000981:diagnostic imaging / Q000473:pathology*; D001315:Australia / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D019229:Dentition, Permanent; D005260:Female; D006801:Humans; D008297:Male; D008336:Mandibular Diseases / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000208:ethnology; D008439:Maxillary Diseases / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000208:ethnology; D008963:Molar; D015995:Prevalence; D011859:Radiography; D014094:Tooth, Deciduous