title: Comparison of different criteria for periodontitis case definition in head and neck cancer individuals.
abstract: OBJECTIVE
  Different periodontitis case definitions have been used in clinical research and epidemiology. The aim of this study was to determine more accurate criterion for the definition of mild and moderate periodontitis case to be applied to head and neck cancer individuals before radiotherapy.
  
  
  METHODS
  The frequency of periodontitis in a sample of 84 individuals was determined according to different diagnostic criteria: (1) Lopez et al. (2002);(2) Hujoel et al. (2006); (3) Beck et al. (1990); (4) Machtei et al. (1992); (5) Tonetti and Claffey (2005); (6) and Page and Eke (2007). All diagnosis were based on the clinical parameters obtained by a single calibrated examiner (Kw = 0.71). The individuals were evaluated before radiotherapy. They received oral hygiene instructions, and the cases diagnosed with periodontitis (Page and Eke 2007) were treated. The gold standard was the definition 6, and the others were compared by means of agreement, sensitivity (SS), specificity (SP), and the area under ROC curve. The kappa test evaluated the agreement between definitions.
  
  
  RESULTS
  The frequency of periodontitis at baseline was 53.6 % (definition 1), 81.0 % (definition 2), 40.5 % (definition 3), 26.2 % (definition 4), 13.1 % (definition 5), and 70.2 % (definition 6). The kappa test showed a moderate agreement between definitions 6 and 2 (59.0 %) and definitions 6 and 1 (56.0 %). The criterion with higher SS (0.92) and SP (0.73) was definition 1.
  
  
  CONCLUSIONS
  Definition 1 was the most accurate criterion to case periodontitis definition to be applied to head and neck cancer individuals.
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, Federal University of Minas Gerais, Avenue Antônio Carlos 6627, Pampulha, 31270-901, Belo Horizonte, Minas Gerais, Brazil, audreybueno@ig.com.br.
authors.forename: Audrey Cristina
authors.initials: AC
authors.lastname: Bueno
authors.forename: Raquel Conceição
authors.initials: RC
authors.lastname: Ferreira
authors.forename: Luis Otávio Miranda
authors.initials: LO
authors.lastname: Cota
authors.forename: Guilherme Carvalho
authors.initials: GC
authors.lastname: Silva
authors.forename: Cláudia Silami
authors.initials: CS
authors.lastname: Magalhães
authors.forename: Allyson Nogueira
authors.initials: AN
authors.lastname: Moreira
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006258:Head and Neck Neoplasms / Q000150:complications*; D006801:Humans; D008875:Middle Aged; D010518:Periodontitis / Q000145:classification / Q000175:diagnosis*; D012372:ROC Curve