[Longitudinal study on periodontal disease activity in treated periodontitis patients]

The aim of this study was to estimate the incidence of periodontal disease activity (PDA) in treated periodontitis patients in a longitudinal survey. Seven periodontitis patients with 170 teeth (970 sites) participated in this 6 to 12 month study. After initial therapy, the clinical parameters including attachment level (AL) were recorded as the baseline data and then repeated every two months. Occlusal stents were used for each patient to assure the accuracy and reproductivity of the attachment level measurements. Detection of > or = 2 mm of new AL between two consecutive visits was required to designate a site as PDA. During the study period, 21 sites out of 970 sites showed PDA. For better accuracy, we calculated the yearly PDA rate based on the 6-month data because not all the seven patients finished the 12-month observation. The estimated PDA rate per year was 2.8%. Data also showed that maxillary bicuspids and molars on both jaws were more susceptible to PDA. Interproximal sites and sites with > or = 6 mm pockets before treatment showed significantly greater PDA rate than buccal (lingual) sites and sites with < or = 4 mm initial pocket depth. Our data supports the tooth specific and site specific concept in periodontal disease.