The efficiency of half-mouth examinations in estimating the prevalence of periodontal disease.

Several studies, including the NIDR 1985 national survey of working adults, have used periodontal examinations of only two quadrants of the mouth to estimate the prevalence of periodontal conditions. To investigate the efficiency of half-mouth periodontal examinations, I compared the results from the examination of all teeth in a sample of 477 dentate elderly people with scores that would have been obtained if randomly selected pairs of quadrants had been examined instead. In this elderly dentate population, relatively little information would have been lost if diagonal half-mouth or same-side half-mouth scores instead of whole-mouth scores had been used to estimate the number or proportion of teeth with periodontal conditions. However, the proportion of people with the less prevalent conditions, i.e., deep pocketing and mobility, was underestimated slightly. Slightly less efficiency was also noted for the less prevalent conditions. These findings suggest that half-mouth recording may be useful for prevalence surveys, but cannot be recommended for incidence surveys or clinical trials, where incremental changes may be small.