title: Use of preexisting radiographs for assessing periodontal disease in epidemiologic studies.
abstract: OBJECTIVE
  This study evaluates the feasibility of obtaining preexisting dental radiographs by mail, the validity of assessing alveolar bone loss from posterior radiographs compared to full mouth, and the validity of alveolar bone loss assessed from radiographs taken at different times.
  
  
  METHODS
  This investigation uses data obtained for a study evaluating associations between oral conditions, blood biomarkers, and coronary heart disease within two large cohorts: the Nurses' Health Study and the Health Professionals Follow-up Study. If consenting participants had dental radiographs, we requested these radiographs from their dentists. Some dentists returned multiple sets of radiographs, which enabled us to conduct this study. A calibrated periodontist read all radiographs with good intraexaminer reliability (r=0.91). We compared posterior radiographs to full mouth (n=121 sets), as well as radiographs taken at different times (mean difference of 5 years) (n=102 pairs).
  
  
  RESULTS
  Of the 812 participants, 81 percent consented and 66 percent provided radiographs. Posterior radiographs underestimated periodontitis (> or =1 site with > or =5 mm alveolar bone loss) prevalence by 6 percent (53.7% vs 57.0%) compared to full mouth, with sensitivity of 0.94 (95% confidence interval [CI]=0.86, 0.98) and specificity of 1. Spearman correlation coefficients comparing mean alveolar bone loss were 0.70 for anterior versus posterior teeth (mean difference=0.48), 0.92 for posterior teeth versus full mouth (mean difference=0.25), and 0.78 for pairs of radiographs taken at different times (mean difference=0.01). The kappa statistic was 0.70 comparing radiographs taken within 5 years and 0.29 when the period extended beyond 5 years.
  
  
  CONCLUSIONS
  Preexisting radiographs are feasible for use in epidemiologic studies and provide valid assessments of periodontal disease.
authors.affiliation: Harvard School of Dental Medicine, Boston MA 02115, USA.
authors.forename: Waranuch
authors.initials: W
authors.lastname: Pitiphat
authors.forename: Constant
authors.initials: C
authors.lastname: Crohin
authors.forename: Paige
authors.initials: P
authors.lastname: Williams
authors.forename: Anwar T
authors.initials: AT
authors.lastname: Merchant
authors.forename: Chester W
authors.initials: CW
authors.lastname: Douglass
authors.forename: Graham A
authors.initials: GA
authors.lastname: Colditz
authors.forename: Kaumudi J
authors.initials: KJ
authors.lastname: Joshipura
mesh_terms: D000328:Adult; D000368:Aged; D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging / Q000453:epidemiology; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D015331:Cohort Studies; D016001:Confidence Intervals; D003327:Coronary Disease / Q000453:epidemiology; D016021:Epidemiologic Studies; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009909:Oral Health; D010510:Periodontal Diseases / Q000000981:diagnostic imaging* / Q000453:epidemiology; D011859:Radiography; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D015415:Biomarkers