title: Space-providing expanded polytetrafluoroethylene devices define alveolar augmentation at dental implants induced by recombinant human bone morphogenetic protein 2 in an absorbable collagen sponge carrier.
abstract: BACKGROUND
  Surgical implantation of recombinant human bone morphogenetic protein 2 (rhBMP-2) in an absorbable collagen sponge carrier (ACS) significantly enhances bone regeneration in horizontal alveolar defects; however, sufficient quantities of bone for implant dentistry are not routinely obtained.
  
  
  OBJECTIVE
  The objective of this proof-of-principle study was to evaluate the potential of a space-providing macroporous expanded polytetrafluoroethylene (ePTFE) device to control volume and geometry of rhBMP-2/ACS-induced alveolar bone augmentation.
  
  
  METHODS
  Bilateral critical-size supra-alveolar periimplant defects were created in four Hound-Labrador mongrel dogs. Two turned and one surface-etched 10 mm titanium dental implants were placed 5 mm into the surgically reduced alveolar ridge creating 5 mm supra-alveolar defects. rhBMP-2/ACS (0.4 mg rhBMP-2) was placed around the exposed dental implants. Additionally, one jaw quadrant in each animal was randomly assigned to receive the dome-shaped macroporous ePTFE device. Mucoperiosteal flaps were advanced for primary wound closure. The animals were euthanized at 8 weeks post surgery for histometric analysis.
  
  
  RESULTS
  The space-providing macroporous ePTFE device defined the volume and geometry of rhBMP-2/ACS-induced bone formation, whereas bone formation at sites receiving rhBMP-2/ACS alone varied considerably. Vertical bone gain at turned dental implants averaged (+/-SD) 4.7 +/-0.2 mm at sites receiving rhBMP-2/ACS and the ePTFE device compared with 3.5 +/-0.9 mm at sites receiving rhBMP-2/ACS only. The corresponding values for rhBMP-2/ACS-induced bone area were 9.6 +/- 0.7 mm2 and 7.5 +/-6.2 mm2. There was a highly significant correlation between induced bone area and the space provided by the ePTFE device (p <.001). There was no difference in induced bone density or bone-implant contact between the two technologies. These observations were consistent with those observed at surface-etched dental implants.
  
  
  CONCLUSIONS
  The data from this study suggest that a space-providing macroporous ePTFE device defines rhBMP-2/ACS-induced alveolar augmentation to provide adequate bone quantities for implant dentistry. The dental implant surface technology does not appear to substantially influence bone formation.
authors.affiliation: Department of Periodontology, Temple University School of Dentistry, Philadelphia, PA 19140, USA. uwikesjo@temple.edu
authors.forename: Ulf M E
authors.initials: UM
authors.lastname: Wikesjö
authors.forename: Mohammed
authors.initials: M
authors.lastname: Qahash
authors.forename: Robert C
authors.initials: RC
authors.lastname: Thomson
authors.forename: Alonzo D
authors.initials: AD
authors.lastname: Cook
authors.forename: Michael D
authors.initials: MD
authors.lastname: Rohrer
authors.forename: John M
authors.initials: JM
authors.lastname: Wozney
authors.forename: W Ross
authors.initials: WR
authors.lastname: Hardwick
mesh_terms: D020341:Absorbable Implants; D000540:Alveolar Ridge Augmentation; D000818:Animals; D015519:Bone Density / Q000187:drug effects; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000008:administration & dosage / Q000627:therapeutic use*; D001861:Bone Regeneration / Q000187:drug effects*; D045662:Dental Etching; D015921:Dental Implants; D004285:Dogs; D004337:Drug Carriers; D005781:Gelatin Sponge, Absorbable / Q000627:therapeutic use*; D016557:Guided Tissue Regeneration, Periodontal / Q000295:instrumentation*; D006490:Hemostatics / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008334:Mandible / Q000601:surgery; D008567:Membranes, Artificial; D016348:Osseointegration; D010012:Osteogenesis / Q000187:drug effects; D011138:Polytetrafluoroethylene; D011897:Random Allocation; D011994:Recombinant Proteins; D014025:Titanium; D016212:Transforming Growth Factor beta / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D015921:Dental Implants; D004337:Drug Carriers; D006490:Hemostatics; D008567:Membranes, Artificial; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2; D011138:Polytetrafluoroethylene; D014025:Titanium