title: Simultaneous versus two-stage implant placement and guided bone regeneration in the canine: histomorphometry at 8 and 16 months.
abstract: OBJECTIVE
  To compare the effect of timing of implant placement and guided bone regeneration (GBR) procedure on osseointegration and newly formed bone at 8 and 16 months.
  
  
  METHODS
  In seven dogs, four different sites were bilaterally established: (1) an implant placed in a 6-month healed (6m-GBR) bovine bone mineral (BBM) grafted site; (2) a simultaneously placed implant with the grafted BBM (Si-GBR) followed by a membrane coverage; (3) an implant placed in a membrane-protected non-grafted defect; and (4) an implant placement in a naturally healed site (Cont). Histomorphometry was obtained at 8 and 16 months post-implant placement. Bone-implant contact (BIC), crestal bone resorption (CBR), vertical intra-bony (VIB) defect, bone (BAF) and particle (PAF) area fractions, and osteoconductivity (CON) levels were measured.
  
  
  RESULTS
  In all sites, BIC ranged between 62% and 79% with no significant differences. PAF ranged from 17% to 27%, with no effect of time. At 8 and 16 months, BAF was significantly smaller at the Si-GBR site when compared with all other sites, CON was significantly greater at the 6m-GBR site, and CBR and VIB were significantly smaller at the 6m-GBR when compared with the Si-GBR sites.
  
  
  CONCLUSIONS
  The simultaneous and delayed techniques both showed a similar osseointegration level over time. However, the staged approach showed enhanced newly formed bone, higher osteoconduction around the grafted mineral, less CBR, and smaller vertical bone defect over time compared with the combined approach.
authors.affiliation: Department of Periodontology, Tel Aviv University, Tel Aviv, Israel. zviartzi@tau.ac.il
authors.forename: Zvi
authors.initials: Z
authors.lastname: Artzi
authors.forename: Carlos E
authors.initials: CE
authors.lastname: Nemcovsky
authors.forename: Haim
authors.initials: H
authors.lastname: Tal
authors.forename: Evgeny
authors.initials: E
authors.lastname: Weinberg
authors.forename: Miron
authors.initials: M
authors.lastname: Weinreb
authors.forename: Hari
authors.initials: H
authors.lastname: Prasad
authors.forename: Michael D
authors.initials: MD
authors.lastname: Rohrer
authors.forename: Avital
authors.initials: A
authors.lastname: Kozlovsky
mesh_terms: D016301:Alveolar Bone Loss / Q000517:prevention & control; D000540:Alveolar Ridge Augmentation / Q000379:methods*; D000818:Animals; D015519:Bone Density; D018786:Bone Substitutes; D003758:Dental Implantation, Endosseous / Q000379:methods*; D004285:Dogs; D016557:Guided Tissue Regeneration, Periodontal / Q000379:methods*; D008297:Male; D016348:Osseointegration; D013997:Time Factors
chemical_list: D018786:Bone Substitutes