Long-Term Results 10 Years After Periodontal Therapy, B. Pretzl, and P. Eickholz, Zentrum fur-Zahn-, Mund- und Kieferheilkunde, Poliklinik für ZEH, Heidelberg, Germany Objectives: The aim of this study was to assess factors contributing to the long-term effect of periodontal treatment 10 years after initiation of antiinfectious therapy. The main outcome variable of this analysis was tooth loss. Methods: 36 adult patients were recruited for the study. Inclusion criteria were full-mouth radiographs from the beginning of therapy and completion of antiinfectious therapy. Clinical examinations including periodontal findings, Plaque (PCR) and Gingival (GBI) Index, samples for analysis of interleukin-1 polymorphism (IL-1), and a detailled questionary on smoking habits, dental care, social status, and nutrition were obtained by the same examiner. Additionally periodontal conditions were surveyed according to the criteria of the Swiss Dental Association. Medical files were searched for initial diagnosis, documentation of tooth loss, regularity of maintenance and prognosis index (Checchi et al. 2002). The statistical analysis was performed with SPSS using linear regression. Results: The following means of tooth loss per patient were observed: gender (male/female): 1.06±1.34/ 1.53±2.20; smoking (no/yes): 1.22±1.95/ 1.56±1.51; IL-1 polymorphism (yes/no): 0.63±0.74/ 1.27±1.33; prognosis (A/B,C): 0.79±1.42/ 1.62±2.06; initial diagnosis (moderate chronic/severe chronic, aggressive periodontitis): 0.67±1.66/ 1.52±1.87; regular maintenance (yes/no): 0.71±0,85/ 2.13±2.47. Stepwise linear multiple regression revealed increased tooth loss for irregular maintenance patients (p=0.017). Conclusions: Some criteria seem to interact with tooth loss whereas only regular maintenance could be proven to be statistically significant preventive of tooth loss. Keywords: GTR, Langzeitergebnisse