Sinus Augmentation Using Rhbmp-2/Acs In A Mini-Pig Model: Influence Of An Adjunctive Ceramic Bone Biomaterial

BackgroundRecombinant human bone morphogenetic protein-2 in an absorbable collagen sponge carrier (rhBMP-2/ACS) has been shown to support significant bone formation when used to augment the maxillary sinus for implant dentistry. Nevertheless, bone biomaterials have been suggested to extend rhBMP-2/ACS with limited support of the merits of such approaches.ObjectivesTo evaluate local bone formation/dental implant osseointegration following implantation of rhBMP-2/ACS combined with a ceramic bone biomaterial using a mini-pig sinus augmentation model.MethodsTwelve adult Gottingen mini-pigs received rhBMP-2/ACS (rhBMP-2 adjusted to 0.43mg/cc) alone or combined with an off-the-shelf biphasic ceramic (15%/85% HA/ss-TCP) biomaterial at 3:1, 1:1 and 1:3 ratios randomized to contra-lateral maxillary sinus sites yielding rhBMP-2/ACS fractions of 100%, 75%, 50% and 25%, respectively. A 4-cc implant volume was used for all sites. Two threaded dental implants (O4.0x11.5mm) were placed at each site. The animals were euthanized at 8weeks for histologic analysis.ResultsSurgical execution and healing were generally uneventful, infraorbital local swelling was observed in all animals until suture removal. rhBMP-2/ACS combined with the ceramic biomaterial did not significantly enhance local bone formation (range 9.01.5 to 9.7 +/- 2.1mm) compared with rhBMP-2/ACS alone (8.6 +/- 1.1mm; p>0.05). Variations in rhBMP-2/ACS to ceramic matrix ratios yielding rhBMP-2 doses approximating 0.4, 0.9, 1.3 and 1.7mg/sinus did not appreciably influence bone formation/osseointegration.ConclusionsWhereas rhBMP-2/ACS supports significant bone formation/osseointegration in the mini-pig sinus augmentation model and thus appears an effective alternative for sinus augmentation procedures, adding a ceramic biomaterial to rhBMP-2/ACS does not produce meaningful biological advantages.