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.

PURPOSE: 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). MATERIALS AND 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. CONCLUSION: Delivery of rhGDF-5 on beta-TCP might have the potential to enhance the results of GBR in peri-implant defects.

Sinus floor augmentation with recombinant human growth and differentiation factor-5 (rhGDF-5): a histological and histomorphometric study in the Goettingen miniature pig.

AIM: The aim of this study was to test the hypothesis that recombinant human growth and differentiation factor-5 (rhGDF-5) enhances bone formation in sinus floor augmentations in miniature pigs. MATERIAL AND METHODS: The maxillary sinus floors in 12 adult female Goettingen minipigs were augmented with beta-tricalcium phosphate (beta-TCP) on one side. The contralateral test side was augmented using two concentrations of rhGDF-5 (400 microg rhGDF-5/g beta-TCP; 800 microg rhGDF-5/g beta-TCP) delivered on beta-TCP (six animals each). One dental implant was inserted into each sinus floor augmentation. After 4 and 12 weeks, histological and histomorphometric assessment of non-decalcified histological specimens was performed. RESULTS: The results showed significantly higher mean values of volume density (VD) of newly formed bone using the concentration of 400 microg/g beta-TCP (22.8%) compared with the respective control (8%) after 4 weeks (P=0.05). The bone-to-implant contact rates were also significantly enhanced after 4 weeks between test sites (400 microg: 41.9%; 800 microg: 40.6%) and control sites (400 microg: 7.8%; 800 microg: 16.4%) (400 microg: P=0.024; 800 microg: P=0.048). CONCLUSION: It is concluded that rhGDF-5 delivered on beta-TCP significantly enhanced early bone formation compared with beta-TCP alone in sinus lift procedures in miniature pigs.

Superior effect of MD05, beta-tricalcium phosphate coated with recombinant human growth/differentiation factor-5, compared to conventional bone substitutes in the rat calvarial defect model.

BACKGROUND: MD05 consists of beta-tricalcium phosphate (beta-TCP) coated with recombinant human growth/differentiation factor-5 (rhGDF-5) and is under evaluation as an osteoinductive and osteoconductive bone graft material for use in dental and maxillofacial applications. The objective of this study was to compare the bone regenerative properties of MD05 with those of conventional commercially available bone substitutes. METHODS: Full-thickness, 6-mm diameter, calvarial critical-size defects (two per animal) were created in adult Sprague-Dawley rats. Groups of rats were implanted with the following: 1) MD05; 2) bovine bone mineral; 3) bovine bone mineral with collagen; 4) bovine bone mineral with synthetic peptide, 5) beta-TCP (from two different manufacturers); or 6) no filling material (sham controls). Blinded macroscopic analysis, histopathologic analysis, and histomorphometric analysis were carried out 6 weeks after implantation. RESULTS: New bone formation assessed histomorphometrically was about five times greater with MD05 than with the other bone substitutes tested, and bone repair was well advanced in MD05-filled defects after 6 weeks. The extent of fibrous tissue and residual implant were significantly lower in the MD05 group. In contrast to the other materials, the use of MD05 was associated with the complete osseous bridging of the defect and with the presence of normal bone marrow. The osteoinductive effect of rhGDF-5 was apparent from the more pronounced bone ingrowth observed with MD05 compared to the beta-TCP carrier alone. All implants showed good biocompatibility. CONCLUSION: MD05 achieved superior bone regeneration compared to conventional materials and is a promising new bone substitute for dental and maxillofacial applications.