title: Long-term tooth retention in chronic periodontitis - results after 18 years of a conservative periodontal treatment regimen in a university setting.
abstract: The longitudinal study assessed the risk of tooth loss under a non-regenerative treatment regimen and aimed to identify prognostic factors for tooth loss.
  
  
  
  Three hundred and fifteen patients (8009 teeth) were examined before (T0) and after active periodontal therapy (APT, T1) as well as after (mean ± SD) 18 ± 6 years of supportive periodontal therapy (SPT, T2). Descriptive statistics and a Cox proportional hazards shared-frailty model were applied.
  
  
  
  Overall, 351 and 816 teeth were lost during APT and SPT, respectively, with 0.15 ± 0.17 teeth being lost per patient and year. Seventy-two percentage patients lost 0-3, 24% 4-9 and 4% ≥10 teeth. The proportion of teeth with probing-pocket depths (PPD) >6 mm was 17.2% (T0), 1.6% (T1) and remained stable at 1.7% up to T2. Tooth loss during SPT was significantly increased in older patients [HR (95% CI): 1.04 (1.01-1.07) per year] and smokers [2.62 (1.34-5.14)], with each mm of PPD [1.35 (1.17-1.56)], in multirooted compared with single-rooted teeth [1.86 (1.36-2.56)] and teeth with bone loss [BL; HR up to 23.6 (12.1-45.6) for BL > 70%].
  
  
  
  The risk of tooth loss was generally low under the provided non-regenerative treatment regimen; a minority of patients were responsible for the majority of teeth lost during SPT.
authors.affiliation: Clinic of Conservative Dentistry and Periodontology, University of Kiel, Kiel, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Graetz
authors.affiliation: Clinic of Conservative Dentistry and Periodontology, University of Kiel, Kiel, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Plaumann
authors.affiliation: Institute of Medical Statistics, Computer Sciences and Documentation, Jena University Hospital, Jena, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Schlattmann
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.identifier: 0000-0002-9099-7750
authors.initials: S
authors.lastname: Sälzer
authors.affiliation: Clinic of Conservative Dentistry and Periodontology, University of Kiel, Kiel, Germany.
authors.forename: Konstantin
authors.initials: K
authors.lastname: Gomer
authors.affiliation: Clinic of Conservative Dentistry and Periodontology, University of Kiel, Kiel, Germany.
authors.forename: Christof
authors.initials: C
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: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D055113:Chronic Periodontitis / Q000150:complications / Q000628:therapy*; D000072700:Conservative Treatment; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D013997:Time Factors; D016388:Tooth Loss / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*; D014495:Universities
keywords: maintenance; periodontal disease; periodontal therapy; risk model; tooth loss