A comparison of four epidemiological methods of assessing periodontal disease

Periodontal disease was assessed using PI and P.D.I. and radiographic and mobility assessments. Analysis of data by worst score in the mouth and by individual teeth indicated that PI did underestimate the severity of periodontal disease. P.D.I. diagnosed destructive periodontal disease in 45.0 per cent of mouths and 38 per cent of teeth considered free of destructive periodontal disease using PI. P.D.I. detects more destructive periodontal disease than PI at the lower radiographic scores (4 and 5); at radiographic scores 6 and 7 the disparity between the P.D.I. and PI decreased. The measurements of mobility underestimated the severity of periodontal disease; ninety five per cent of all teeth examined were considered to have a mobility score of 0 whereas 20 per cent were considered free of periodontal disease using PI. Radiographic examination did not add significantly to the PI and P.D.I. examinations.