title: Vertical ridge augmentation with guided bone regeneration in association with dental implants: an experimental study in dogs.
abstract: OBJECTIVE
  To evaluate the effect of using guided bone regeneration (GBR) with a titanium-reinforced e-PTFE membrane in alveolar bone defects with titanium implants.
  
  
  METHODS
  Following extraction of three mandibular premolars and a molar on both sides of the jaw in three dogs, alveolar bone defects (depth: 5-7 mm) were produced. After 4 months, three implants were inserted into each defect to a depth of approximately 4 mm, so that their coronal portion was protruding about 5 mm. Four sides in the dogs were assigned to a test group and the remaining two sides to a control group. The 12 implants in the test group were covered with a reinforced e-PTFE membrane. The space under the membrane was filled with peripheral venous blood from the animal, and the flaps were sutured over the membrane. The six control implants received no membrane before the suturing of the flaps to complete wound closure. The animals were sacrificed after 6 months, and non-decalcified histological specimens of the implants and surrounding tissues were prepared.
  
  
  RESULTS
  Histologic and histomorphometric analyses revealed a significantly (Mann-Whitney test; P=0.08) larger amount of bone fill in the test group (mean=57.42%) than in the controls (mean=11.65%), and clinical evaluation of one test site showed that the implants were completely covered with tissue resembling bone. In most of the specimens, bone had grown in height close to, or in direct contact with the membrane. However, the new bone generally was not in direct contact with the implants. Regularly, a zone of dense connective tissue was interposed between the implants and the newly formed bone.
  
  
  CONCLUSIONS
  The formation of even considerable amounts of bone following vertical ridge augmentation with GBR and implants was not accompanied by predictable osseointegration of the implants.
authors.affiliation: Department of Periodontology, School of Dentistry, University of Milan, Milan, Italy. m.simion@unimi.it
authors.forename: Massimo
authors.initials: M
authors.lastname: Simion
authors.forename: Christer
authors.initials: C
authors.lastname: Dahlin
authors.forename: Isabella
authors.initials: I
authors.lastname: Rocchietta
authors.forename: Andreas
authors.initials: A
authors.lastname: Stavropoulos
authors.forename: Raquel
authors.initials: R
authors.lastname: Sanchez
authors.forename: Thorkild
authors.initials: T
authors.lastname: Karring
mesh_terms: D016301:Alveolar Bone Loss / Q000473:pathology / Q000601:surgery; D000539:Alveolar Process / Q000473:pathology; D000540:Alveolar Ridge Augmentation / Q000379:methods*; D000818:Animals; D001672:Biocompatible Materials; D001861:Bone Regeneration / Q000502:physiology*; D003238:Connective Tissue / Q000473:pathology; D003758:Dental Implantation, Endosseous / Q000379:methods; D015921:Dental Implants; D004285:Dogs; D016557:Guided Tissue Regeneration, Periodontal / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D008334:Mandible / Q000473:pathology / Q000601:surgery; D008567:Membranes, Artificial; D010012:Osteogenesis / Q000502:physiology; D011138:Polytetrafluoroethylene; D011897:Random Allocation; D013524:Surgical Flaps; D014025:Titanium
chemical_list: D001672:Biocompatible Materials; D015921:Dental Implants; D008567:Membranes, Artificial; D011138:Polytetrafluoroethylene; D014025:Titanium