title: The effects of recombinant human growth/differentiation factor-5 (rhGDF-5) on bone regeneration around titanium dental implants in barrier membrane-protected defects: a pilot study in the mandible of beagle dogs.
abstract: OBJECTIVE
  This dog study sought to evaluate guided bone regeneration (GBR) in peri-implant defects following implantation of beta-tricalcium phosphate (beta-TCP) with and without osteoinductive recombinant human growth/differentiation factor-5 (rhGDF-5).
  
  
  METHODS
  In five beagle dogs, all mandibular premolars and the first molar were extracted. After 2 months, six buccolingual critical-size defects were created, and an implant was inserted into the center of each defect. One defect was filled with beta-TCP coated with rhGDF-5 (600 microg/g beta-TCP) and covered with a titanium-reinforced e-PTFE membrane (GDF group). A second defect received the same treatment, but pure uncoated beta-TCP was used (TCP group). A third defect was filled with beta-TCP mixed with autograft and not protected with a membrane (control group). The remaining three defects were filled with other biomaterials. After 2 months, total new bone area, regenerated bone height, and residual amount of beta-TCP were determined histomorphometrically.
  
  
  RESULTS
  All implants osseointegrated. One membrane in each group became exposed. Mean new bone area for GDF, TCP, and control sites was 43.9 +/- 18.7 mm2, 32.3 +/- 16.1 mm2, and 13.1 +/- 4.0 mm2, respectively, with a significant difference between GDF and control groups. Mean regenerated bone height was 103.8 +/- 29.7%, 75.4 +/- 36.6%, and 67.2 +/- 19.1% for the GDF, TCP, and control groups, respectively. Mean residual matrix volumes were 25.9 +/- 13.6%, 30.0 +/- 13.0%, and 13.4 +/- 6.5%, respectively. Membrane protection of peri-implant defects filled with beta-TCP resulted in a stronger effect on bone regeneration, although this was not statistically significant. The most pronounced regenerative results were achieved in rhGDF-5/beta-TCP filled membrane-protected defects.
  
  
  CONCLUSIONS
  Delivery of rhGDF-5 on beta-TCP might have the potential to enhance the results of GBR in peri-implant defects.
authors.affiliation: Department of Prosthodontics, School of Dental Medicine, Bavarian Julius-Maximilians-University, Würzburg, Germany. dw@max-17.de
authors.forename: Dietmar
authors.initials: D
authors.lastname: Weng
authors.forename: Sylke
authors.initials: S
authors.lastname: Poehling
authors.forename: Susanne
authors.initials: S
authors.lastname: Pippig
authors.forename: Matthias
authors.initials: M
authors.lastname: Bell
authors.forename: Ernst-Jürgen
authors.initials: EJ
authors.lastname: Richter
authors.forename: Otto
authors.initials: O
authors.lastname: Zuhr
authors.forename: Markus B
authors.initials: MB
authors.lastname: Hürzeler