Therapy-resistant periodontitis (I). Clinical and treatment characteristics.

The aim of this study was to evaluate the clinical criteria for classification of 2 different patient groups. From retrospective comparisons of pocket probing depth (PPD) charts, we classified 22 patients as either non-responding or responding to periodontal treatment. The non-responding patient group, in comparison with the responding patient group, showed a profile over time of less PPD reduction in response to periodontal treatment. Information registered in each patient's file regarding clinical periodontal conditions, as well as treatment procedure characteristics, was gathered. Bivariate analyses were performed. 3 clinical variables (frequency of mean PPD > or = 6 mm during the treatment period; at final registration; and the mobility score at the final registration) indicated that 2 separate patient groups had been identified. Although the patient groups exhibited advanced periodontitis at the beginning of treatment, both groups at the end of treatment had lost very few (1-2) teeth, probably as a result of regular supportive treatment. The characteristics of the selected clinical criteria warrant the use of these 2 patient groups in further analysis of the relation of psychosocial stress and microbiological characteristics of therapy-resistant periodontitis.