Validity of the Community Periodontal Index of Treatment Needs’ (CPITN) for population periodontitis screening Validação do Community Periodontal Index of Treatment Needs’ (CPITN) para identificação de periodontite em populações

The aim of the present study was to validate two versions of CPITN for periodontitis diagnosis. A sample of 400 individuals underwent full mouth periodontal examination including Clinical Attachment Loss, Periodontal Pocket Depth, and Sub-gingival Calculus. Full and partial CPITN versions were derived from this exam (gold standard). Contingency tables were constructed and operational characteristics obtained, as well as ROC curves. The results show 58% sensitivity for full CPITN and 80.6% specificity. Positive and negative predictive values were 87% and 46.3%, respectively. According to the test, estimated periodontitis prevalence was 46%, while the figure obtained with the gold standard was 69%. The partial version of the CPITN showed 50% sensitivity and 87.1% specificity. Positive and negative predictive values were 89.6% and 43.9%, respectively. Estimated periodontitis prevalence, through partial CPITN, was 30.5%. Adjusted global agreement (kappa) for partial and full CPITN was 0.32 and 0.29, respectively. Both CPITN versions disagreed significantly with gold standard results (chi-square p < 0.001). As a conclusion, both total and partial CPITN failed to reflect the real periodontal status of the sample. Validation Studies; Periodontal Index; Periodontitis Background Instruments for periodontitis screening are commonly applied to populations in epidemiological studies of oral health. Several tests or indexes have been developed for this purpose, mainly due to a growing impression of inadequacy in the existing instruments. Another reason for the development of new instruments has been the search for efficient and simple ways to screen populations for periodontitis 1,2,3,4. The criteria used for periodontitis diagnosis vary greatly, but it is agreed that monitoring the attachment level is the most reasonable way to access activity of periodontal destruction 5,6,7. Since it is known that the feasibility of repeated measurements in healthy populations to assess periodontal disease progression is difficult, mainly due to economic, logistic, and statistical reasons, researchers are expected to conducted screening of periodontal disease with the available instruments. Few instruments available for periodontal screening have been validated against a standard exam, and the performance of these instruments for screening purposes is unpredictable when the disease status of the population is unknown. Validating a test is necessary for screening, and it has been determined that some of the periodontal screening tests tend to underestimate disease prevalence 1,3,6,8,9,10,11,12,13. It has also been reported that in some situations peBassani DG et al. 278 Cad. Saúde Pública, Rio de Janeiro, 22(2):277-283, fev, 2006 riodontal screening instruments may overestimate disease 6,8,14,15,16,17,18,19. Operational characteristics of screening instruments can be assessed by validation studies. It is taken for granted that periodontal disease varies considerably among populations 16,17,20,21,22 and that severe limitations in the current disease descriptors exist 23,24,25. These points should be considered when evaluating data from studies describing the periodontal health status of populations through these instruments. The use of screening instruments for periodontitis is not questioned, although the adequacy of the instruments should be considered more carefully. Several authors have proposed short tests for periodontal screening 2,4,26,27. The Community Periodontal Index of Treatment Needs (CPITN) proposition in 1982 and the rapid acceptance of this instrument provided the scientific community with an enormous amount of epidemiological data collected through it. Based on the limitations identified by several authors during years of research, the World Health Organization (WHO) proposed a few changes to the CPITN in 1987 and again in 1997. Nevertheless, the instrument’s diagnostic criteria were basically unaffected by the modifications. There is a lack of studies comparing CPITN to standard exams/diagnostic criteria. The purpose of the present study is to assess CPITN’s operational characteristics. Understanding the performance of the instrument and specifically the assessment of its sensitivity and specificity will improve interpretations of the disease prevalence rates estimated with the CPITN.