title: Long-term tooth survival following regenerative treatment of intrabony defects.
abstract: BACKGROUND
  The longevity of the clinical benefits of guided tissue regeneration (GTR) has not been fully explored. The aim of this investigation was to assess the long-term survival of GTR treated sites in terms of clinical attachment level (CAL) stability and tooth loss.
  
  
  METHODS
  A total of 175 patients with one deep intrabony defect were selected for a retrospective investigation of tooth retention and CAL stability. All sites had been treated with GTR more than 2 years previously and had received full periodontal examinations every 2 years for up to 16 years. Definitions of events for survival analyses were tooth loss, loss of > or = 2 mm compared with the CAL observed before GTR treatment, and loss of > or = 2 mm compared with the CAL observed 1 year after completion of GTR.
  
  
  RESULTS
  Teeth were severely compromised by the presence of CAL loss of 10.7 +/- 2.4 mm, probing depths of 8.7 +/- 2.3 mm and deep intrabony defects (average depth 6.6 +/- 2.1 mm). After GTR, CAL gains were 4.6 +/- 2 mm. Average follow up was 8 +/- 3.4 years; 66.9% of subjects strictly complied with a periodontal maintenance program. Tooth survival was greater than 96% more than 10 years after GTR. CAL was equal or coronal with respect to pretreatment in 92% of cases followed for 15 years after treatment, while loss of CAL compared to the 1-year post-GTR result was observed in 37.8% of cases. Cox proportional hazard models indicated that incidence-free survival was negatively affected by smoking and positively affected by full compliance with a periodontal maintenance program in a specialist practice.
  
  
  CONCLUSIONS
  Within the limits of this study, data suggest that tooth retention and clinical improvements following GTR treatment of intrabony defects can be maintained long term in the great majority of cases and thus that regenerative periodontal treatment represents an important alternative for the management of severely compromised teeth.
authors.affiliation: Department of Periodontology, Eastman Dental Institute, University College London, London, UK.
authors.forename: Pierpaolo
authors.initials: P
authors.lastname: Cortellini
authors.forename: Maurizio S
authors.initials: MS
authors.lastname: Tonetti
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016301:Alveolar Bone Loss / Q000601:surgery*; D001861:Bone Regeneration / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D016557:Guided Tissue Regeneration, Periodontal; D006801:Humans; D015993:Life Tables; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009910:Oral Hygiene; D017622:Periodontal Attachment Loss / Q000517:prevention & control; D010514:Periodontal Pocket / Q000517:prevention & control; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012907:Smoking / Q000009:adverse effects; D016019:Survival Analysis; D015996:Survival Rate; D016388:Tooth Loss / Q000517:prevention & control