Comparative evaluation of indices and partial-mouth periodontal protocols for epidemiological surveys

Objective : To compare the Community Periodontal Index (CPI), the CPI modified and three partial-mouth periodontal protocols for estimates of prevalence, severity and extent of periodontitis in populations. Method: a convenience sample of 350 individuals (aged 35 to 74 years) from Sao Paulo underwent a full-mouth periodontal examination (FMPE) which assessed pocket depth (PD), clinical attachment level (CAL) and bleeding on probing on six sites per tooth. The CPI, CPI modified (CPIm) and three partial-mouth protocols examination (PMPE)-half-mouth 6 sites, full- and half-mouth 3 sites-were derived from the records of the FMPE and have been compared for sensitivity, absolute bias, relative bias and inflation factor in estimates of periodontitis. Results: Significant differences were found in periodontitis prevalence estimates between PMPE, in different case definitions, with relative biases ranging from -10% to -55%. The CPIm had sensitivity of 100% for gingivitis and PD ≥4 mm prevalence, and 80% for moderate and severe periodontitis in relation to FMPE, while for CPI such estimates were 70% and 50%, respectively. The full-mouth 3 sites protocol was similar to the CPIm, regarding the prevalence estimate, but CPIm overestimated severity and extent of periodontitis. The random half-mouth protocols presented low sensitivity to estimate periodontitis prevalence, although they presented small biases for severity and extension (<2.0%). Conclusion : The CPIm and the full-mouth 3 sites protocol presented satisfactory sensitivity to estimate prevalence of periodontitis in populations, being superior to the previous CPI and to the random half-mouth protocols. However, accuracy of estimates may vary with the case definition and population characteristics.