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

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. Purpose: 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. Materials and 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 domeshaped 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 mm ² and 7.5 ± 6.2 mm ². 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.