Patient-related prognostic risk factors in severe periodontitis patients after periodontal therapy

We created a database of patient information and laboratory measurements for patients with severe periodontitis, and assessed how the patient-related prognostic factors and treatment response might be related to the risk of tooth loss and progression (recurrence) of periodontal disease during supportive periodontal therapy (SPT). To create the database, we retrospectively collected the case data of 208 patients with severe periodontitis receiving SPT at 11 dental centers. Data included the medical history, treatment history and laboratory measurements related to periodontitis and the general health status at the time of the first consultation, after scaling and root planing (SRP), at the start of SPT, and at the latest SPT session. Patients were defined as having therapy-resistant periodontitis (TRP) if the percentage of sites with a reduction of the periodontal pocket probing depth? (PD) of 2 mm or more from a baseline of 6 mm or more after SRP was less than 70%. Logistic regression analysis and the Kaplan-Meier survival regression method were used to analyze the risk factors for tooth loss and recurrence of periodontitis. There were no significant associations between the risk factors for tooth loss and the various patient-related prognostic factors at the first consultation, however, the number of teeth lost and a history of smoking were significant risk factors for the recurrence of periodontitis. TRP diagnosis was a significant risk factor for tooth loss (OR：2.81, p＝0.006), and patient compliance (regular vs. irregular visits) was a significant risk factor for periodontitis recurrence (OR：3.85, p＜0.001). Based on the survival curve analysis for the prediction of tooth loss, there was a tendency towards an increase of the event incidence rate immediately after the start of SPT in TRP patients and non-compliers, and at about 5 years after the start of SPT in high-risk patients identified by the periodontal risk assessment model, although only the latter was statistically significant (log-rank test, p＝0.0315). The results of the present study demonstrated the prospective usefulness of TRP diagnosis for assessing the prognosis in patients with severe periodontitis. They also suggested that careful attention to utilizing the characteristics of the various techniques for diagnosing patient-related risk factors may increase the accuracy of risk prediction. Nihon Shishubyo Gakkai Kaishi (J Jpn Soc Periodontol) 55(2)：170-182, 2013.