title: Long-term stability of contour augmentation in the esthetic zone: histologic and histomorphometric evaluation of 12 human biopsies 14 to 80 months after augmentation.
abstract: BACKGROUND
  Contour augmentation around early-placed implants (Type 2 placement) using autogenous bone chips combined with deproteinized bovine bone mineral (DBBM) and a collagen barrier membrane has been documented to predictably provide esthetically satisfactory clinical outcomes. In addition, recent data from cone beam computed tomography studies have shown the augmented volume to be stable long-term. However, no human histologic data are available to document the tissue reactions to this bone augmentation procedure.
  
  
  METHODS
  Over an 8-year period, 12 biopsies were harvested 14 to 80 months after implant placement with simultaneous contour augmentation in 10 patients. The biopsies were subjected to histologic and histomorphometric analysis.
  
  
  RESULTS
  The biopsies consisted of 32.0% ± 9.6% DBBM particles and 40.6% ± 14.6% mature bone. 70.3% ± 14.5% of the DBBM particle surfaces were covered with bone. On the remaining surface, multinucleated giant cells with varying intensity of tartrate-resistant acid phosphatase staining were regularly present. No signs of inflammation were visible, and no tendency toward a decreasing volume fraction of DBBM over time was observed.
  
  
  CONCLUSIONS
  The present study confirms previous findings that osseointegrated DBBM particles do not tend to undergo substitution over time. This low substitution rate may be the reason behind the clinically and radiographically documented long-term stability of contour augmentation using a combination of autogenous bone chips, DBBM particles, and a collagen membrane.
authors.affiliation: Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Simon S
authors.initials: SS
authors.lastname: Jensen
authors.forename: Dieter D
authors.initials: DD
authors.lastname: Bosshardt
authors.forename: Reinhard
authors.initials: R
authors.lastname: Gruber
authors.forename: Daniel
authors.initials: D
authors.lastname: Buser
mesh_terms: D000135:Acid Phosphatase / Q000032:analysis; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000539:Alveolar Process / Q000473:pathology*; D000540:Alveolar Ridge Augmentation / Q000379:methods*; D000818:Animals; D064592:Autografts / Q000637:transplantation; D001706:Biopsy / Q000379:methods*; D018786:Bone Substitutes / Q000627:therapeutic use; D016025:Bone Transplantation / Q000379:methods; D002417:Cattle; D003094:Collagen; D015921:Dental Implants; D004955:Esthetics, Dental; D005260:Female; D005500:Follow-Up Studies; D015726:Giant Cells / Q000473:pathology; D006801:Humans; D007527:Isoenzymes / Q000032:analysis; D008137:Longitudinal Studies; D008297:Male; D008567:Membranes, Artificial; D008875:Middle Aged; D016348:Osseointegration / Q000502:physiology; D010012:Osteogenesis / Q000502:physiology; D000071681:Tartrate-Resistant Acid Phosphatase; D016896:Treatment Outcome
chemical_list: D018786:Bone Substitutes; D015921:Dental Implants; D007527:Isoenzymes; D008567:Membranes, Artificial; D003094:Collagen; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase
keywords: Biocompatible materials; bone regeneration; bone transplantation; clinical trial; histology; reconstructive surgical procedures