Alveolar ridge augmentation using implants coated with recombinant human bone morphogenetic protein-2: radiographic observations

Objectives: Effective carrier technologies and dosing appear critical for the successful use of bone morphogenetic proteins (BMPs). This study evaluated radiographically the potential of a purpose‐designed titanium porous‐oxide implant surface combined with recombinant human BMP‐2 (rhBMP‐2) to stimulate alveolar ridge augmentation. Material and methods: Twelve young‐adult Labrador dogs were used. Three 10‐mm titanium implants per jaw quadrant were placed 5 mm into the alveolar ridge following extraction of the premolar teeth and reduction of alveolar ridge. Six animals received implants coated with rhBMP‐2 at 0.75 or 1.5 mg/ml randomized to contralateral jaw quadrants. Another six animals received implants coated with rhBMP‐2 at 3 mg/ml or uncoated control using the same split‐mouth design. The mucoperiosteal flaps were advanced, adapted, and sutured to submerge the implants. Radiographic registrations were made immediately postsurgery (baseline), and at weeks 4 and 8 (end of study). Results: rhBMP‐2‐coated implants exhibited robust radiographic bone formation extending to and above the implant platform from week 4 (P<0.01). Some rhBMP‐2‐coated implants showed voids within the newly formed bone that gradually resolved and/or implant displacement, being severe in two animals receiving implants coated with rhBMP‐2 at 3 mg/ml. Controls showed limited, if any, new bone formation at weeks 4 and 8 postsurgery. There were no significant differences among the rhBMP‐2 groups in bone gain. Conclusions: The titanium porous‐oxide surface serves as an effective carrier for rhBMP‐2, showing a clinically significant potential to stimulate local bone formation. With the carrier technology used, therapeutic dosage appears to be in the range of 0.75–1.5 mg/ml.