title: Prognostic factors for the loss of molars--an 18-years retrospective cohort study.
abstract: OBJECTIVE
  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.
authors.affiliation: Clinic of Conservative Dentistry and Periodontology, University of Kiel, Kiel, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Graetz
authors.affiliation: Unit of Periodontology, School of Dentistry, University of Greifswald, Greifswald, Germany.
authors.forename: Svenja
authors.initials: S
authors.lastname: Schützhold
authors.affiliation: Clinic of Conservative Dentistry and Periodontology, University of Kiel, Kiel, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Plaumann
authors.affiliation: Clinic of Conservative Dentistry and Periodontology, University of Kiel, Kiel, Germany.
authors.forename: Maren
authors.initials: M
authors.lastname: Kahl
authors.affiliation: Clinic of Conservative Dentistry and Periodontology, University of Kiel, Kiel, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Springer
authors.affiliation: Clinic of Conservative Dentistry and Periodontology, University of Kiel, Kiel, Germany.
authors.forename: Sonja
authors.initials: S
authors.lastname: Sälzer
authors.affiliation: Unit of Periodontology, School of Dentistry, University of Greifswald, Greifswald, Germany.
authors.forename: Birte
authors.initials: B
authors.lastname: Holtfreter
authors.affiliation: Unit of Periodontology, School of Dentistry, University of Greifswald, Greifswald, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kocher
authors.affiliation: Clinic of Conservative Dentistry and Periodontology, University of Kiel, Kiel, Germany.
authors.forename: Christof E
authors.initials: CE
authors.lastname: Dörfer
authors.affiliation: Department of Operative and Preventive Dentistry, Charité University of Berlin, Berlin, Germany.
authors.forename: Falk
authors.initials: F
authors.lastname: Schwendicke
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D017823:Furcation Defects / Q000601:surgery; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D008963:Molar; D010514:Periodontal Pocket / Q000628:therapy; D011379:Prognosis; D012189:Retrospective Studies; D016388:Tooth Loss; D016896:Treatment Outcome; D055815:Young Adult
keywords: bone loss; furcation involvement; periodontitis; supportive periodontal therapy; tooth loss