Long-term Results 10 Years after Periodontal Therapy. 2. Tooth-related Factors

Objective: Evaluation of tooth-related factors influencing long-term success of systematic periodontal therapy. Main outcome variable for this analysis was tooth loss. Methods: 50 patients were consecutively recruited. Inclusion criteria were antiinfectious therapy 10 years ago by the same therapist (PE) and a complete set of intraoral radiographs obtained at the initiation of therapy. Clinical examinations, sampling for interleukin-1 polymorphism test, and questionnaire regarding smoking, nutrition, oral hygiene, and social status were performed by the same examiner (BP). Tooth loss, type, and location as well as frequency of supportive periodontal therapy (SPT) were recorded from patients‘ charts. Each tooth was evaluated for bone loss in per cent of root length and type of bone loss (vertical/horizontal) on the radiographs by another examiner (JK). Multilevel regression analysis was used for statistical analysis. Results: From a total of 1138 teeth 81 teeth were lost in a period of 10 years (7%). Initially 336 teeth exhibited a bone loss up to 20% (tooth loss 3%), 432 up to 40% (4%), 252 up to 60% (11%), 82 up to 80% (18%), and 36 > 80% (33%). 546 were located in the maxilla, 592 in the mandible. Under frequent SPT (30 patients, 697 teeth) tooth loss amounted to 3%, without SPT to 10%. Multilevel regression analysis identified the following factors as preventive against tooth loss: frequent SPT (p = 0.003), little bone loss (p < 0.001), anterior teeth (p < 0.001), location in mandible (p < 0.001). Conclusion: Little initial bone loss, mandibular as well as anterior tooth location, and frequent SPT are positive predictors for tooth retention. This study was supported by Institut für angewandte Immunologie (Zuchwil/Schweiz).