title: Accuracy of partial-mouth examination protocols for extent and severity estimates of periodontitis: a study in a Chinese population with chronic periodontitis.
abstract: BACKGROUND
  Partial-mouth periodontal examination (PMPE) has been widely used in periodontal epidemiologic studies. In this study, the authors evaluate the accuracy of extent and severity estimates from PMPE protocols in a Chinese population.
  
  
  METHODS
  The study enrolled 200 individuals with periodontitis, ages 22 to 64 years. Full-mouth examination was performed to determine probing depth (PD), attachment loss (AL), and bleeding on probing (BOP) at mesio-buccal (MB), mid-buccal (B), disto-buccal (DB), mesio-lingual (ML), mid-lingual (L), and disto-lingual (DL) sites per tooth. Extent and severity estimates from 15 PMPE protocols were derived from and compared to full-mouth data. Relative bias (RB) and intraclass correlation coefficients (ICCs) were calculated. Bland-Altman plots were used to evaluate the agreement patterns across disease levels.
  
  
  RESULTS
  Of the 15 PMPE protocols, the random half-mouth six-sites per tooth (r6sites) protocol performed best in both extent (AL ≥ 2, ≥ 4, or ≥ 6 mm; PD ≥ 4 or ≥ 6 mm; and BOP) and severity (AL and PD) estimates, with RB within 5.0% and ICCs ≥ 0.950 in most cases. MB-B-DB and MB-B-DL protocols generally resulted in RB within 20.0% for extent and within 5.0% for severity. Protocols involving only interproximal sites (MB-DB, MB-DL, and MB-DB-ML-DL) showed good accuracy in AL (RB within 20.0% for extent and within 3.0% for severity), but overestimated PD (RB 12.5% to 54.2% for extent and >10.0% for severity). The community periodontal index teeth protocol caused severe overestimation of up to 110.4% for extent and 14.6% for severity.
  
  
  CONCLUSIONS
  The r6sites protocol is best for assessing extent and severity for AL, PD, and BOP under the study conditions.
authors.affiliation: Department of Periodontology, School and Hospital of Stomatology, Peking University, Beijing, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Chu
authors.forename: Xiangying
authors.initials: X
authors.lastname: Ouyang
mesh_terms: D000328:Adult; D000465:Algorithms; D015982:Bias; D002681:China; D055113:Chronic Periodontitis / Q000145:classification*; D003430:Cross-Sectional Studies; D005260:Female; D005884:Gingival Hemorrhage / Q000145:classification; D006801:Humans; D008297:Male; D008875:Middle Aged; D017622:Periodontal Attachment Loss / Q000145:classification; D010512:Periodontal Index; D010514:Periodontal Pocket / Q000145:classification; D015203:Reproducibility of Results; D055815:Young Adult
keywords: Bias (epidemiology); health surveys; oral examination; periodontal index; periodontitis; severity of illness index