Sinus augmentation using a mini-pig model: Effect of ceramic and allogeneic bone biomaterials

Background: Present clinical practice broadly relies on off-the-shelf allogeneic, xenogeneic or synthetic bone biomaterials in support of sinus augmentation. Also, recombinant human bone morphogenetic protein-2 in an absorbable collagen sponge carrier (rhBMP-2/ACS) has been shown to support clinically relevant bone formation when used to augment the maxillary sinus. Objectives: To evaluate local bone formation/dental implant osseointegration following implantation of two particulate bone biomaterials using the mini-pig sinus augmentation model. Methods: Nine adult Gottingen mini-pigs were used for evaluation of a biphasic ceramic (15%/85% HA/beta-TCP) and an allogeneic mineralized bone biomaterial. Treatments randomized to contralateral sinus sites included sham-surgery (control) and biomaterials. Two threaded dental implants (empty set4.0 x 11.5 mm) were placed at each sinus site. The animals were euthanized at 8 weeks for histologic analysis. Results: Execution of the surgical protocol and healing was unremarkable. Limited infraorbital swelling was observed until suture removal. The biphasic ceramic and allogeneic bone biomaterials produced significantly increased bone formation (5.2 +/- 1.9 mm and 4.9 +/- 1.6 mm vs. 2.6 +/- 0.5 mm, p < 0.05) and osseointegration (18.0 +/- 6.0% and 25.1 +/- 18.2% vs. 10.1 +/- 8.0%, p < 0.05) over the sham-surgery control. No significant differences were observed between biomaterials. Conclusions: Implantation of biphasic ceramic or allogeneic bone biomaterials enhances bone formation in the mini-pig maxillary sinus, however, dental implant bone support is incomplete resulting in overall limited osseointegration.