Prognostic factors for the loss of molars--an 18-years retrospective cohort study.

Aim: The aim of this study was to identify long-term prognostic factors for the loss of molars with different degrees of furcation involvement (FI) during supportive periodontal therapy (SPT).

Methods: Three hundred and seventy-nine compliant subjects with 2373 molars at baseline were retrospectively assessed. After nonsurgical (n = 76) or surgical (n = 303) non-regenerative active periodontal therapy (APT: T0-T1), patients remained under SPT (T1-T2) for 18.3 ± 5.5 (9-30.8) years. Association between tooth- and subject-related factors with tooth loss was assessed using multilevel Cox regression-analysis.

Results: During APT 159 and during SPT 438 molars were extracted in 256 subjects, respectively, yielding an overall survival of 74.8% (T2). Survival probabilities after 15-years of SPT were 92.4% for molars with FI-0 compared to FI-1 = 85.6%, FI-2 = 74.9% and FI-3 = 62.3%. The risk of molar loss was significantly increased for teeth with FI-3 (hazard ratio: 2.39 [95% confidence interval: 1.54-3.70]), bone loss >50% (2.16 [1.36-3.42]), mobile teeth (2.07 [1.51-2.84]), maxillary molars (1.44 [1.12-1.85]) and endodontically treated teeth (1.89 [1.58-2.26]). For each mm of mean residual pocket probing depth, the hazard of tooth loss increased 1.89-fold (1.58-2.26). On a subject level, for each year of age, HR was 1.03 (1.01-1.05).

Conclusions: Furcation involvement, bone loss, tooth mobility, mean pocket depth and age strongly predicted tooth loss during SPT. Long-term retention of periodontally compromised molars was possible via conservative non-regenerative active and supportive therapy.