ObjectivesIn this retrospective study, we compared tooth loss between patients receiving periodontal therapy (PT) in four German university centres, stratified according to periodontal treatment phase. Materials and MethodsOverall, 896 patients (Kiel (KI) n = 391; Greifswald (GW) n = 282; Heidelberg (HD) n = 174; Frankfurt a.M. (F) n = 49) were examined initially (T0), after active periodontal therapy (APT, T1) and after supportive periodontal therapy (SPT, T2). Descriptive analyses and multivariable negative binomial regression models were performed. ResultsFollow-up periods differed significantly between the centres, ranging between 6.7 ± 3.0 (GW) and 18.2 ± 5.5 (KI) years (p < 0.001). At T0, age, gender, smoking and diabetes showed notable regional distinctions (p < 0.001). However, the number of teeth per patient was similar (between 24.0 ± 4.6 (F) and 24.5 ± 4.1 (HD); p = 0.27). During PT, the number of extracted teeth differed significantly between centres, with greater differences during SPT (0.9 ± 1.8 (GW) to 2.3 ± 2.8 (KI), p < 0.001) compared to APT (0.4 ± 0.9 (F) to 1.0 ± 2.1 (KI), p = 0.02). Annual tooth loss during SPT remained low in all centres (between 0.10 ± 0.14 (F) to 0.15 ± 0.30 (HD), p < 0.001). ConclusionWithin the limitation of the study, PT leads to a low risk of tooth loss in all university centres irrespective of patients’ baseline characteristics. Clinical RelevanceWithin the limitations of this retrospective investigation, long-term tooth retention seems to be feasible for most patients, as long as a systematic and structured treatment approach is applied.