Partial-mouth periodontal examination protocol for estimating periodontitis extent and severity in a US population.

We have previously demonstrated that half-mouth four-site periodontal examination protocol performed well in estimating periodontitis prevalence. This study aimed to assess biases associated with this same protocol in estimating periodontitis extent and severity in a United States population. Periodontitis extent as determined by percentage of sites with clinical attachment loss (CAL) ≥3, and ≥5 mm and severity as determined by mean CAL were calculated for full-mouth examination and half-mouth four-site protocol based on 3734 adults sampled from the National Health and Nutrition Examination Survey 2009-2010. Probing depth was excluded because of low data reliability. The comparison between full-mouth and half-mouth assessments was based on bias, relative bias, Wilcoxon signed-rank test, and intra-class correlation coefficient (ICC). For full-mouth examination, periodontitis extent was 21.2% for CAL ≥3 mm and 6.9% for CAL ≥5 mm; periodontitis severity (mean CAL) was 1.73 mm. Half-mouth four-site protocol provided bias -1.2% and relative bias -5.7% for extent (CAL ≥3 mm). Corresponding numbers were -0.3% and 4.3% for extent (CAL ≥5 mm), -0.05 mm and -2.9% for severity. Although the difference between full-mouth and half-mouth assessments was statistically significant, ICCs between them were ≥0.96 for extent (CAL ≥3, 5 mm), and severity (mean CAL). Half-mouth four-site protocol performed well in estimating periodontitis extent and severity based on CAL. Therefore, this protocol should be considered for periodontitis surveillance.