The management of lost bone tissue due to congenital abnormalities, trauma, or cancer treatment poses a challenge to oral and maxillofacial surgeons. The highly vascularized nature of the bone tissue results in a great capacity to heal and remodel without scarring8. Nevertheless, bone loss represents a major clinical problem in reconstructive head and neck surgery, and autologous grafting is still the therapeutic gold standard in reconstructive surgery. This concept, however, has serious limitations related to the limited amount of tissue that can be harvested, increased risk of infection, or recurrent pain. Alternative therapeutic approaches have proposed osteoconduction, guided bone regeneration, osteodistraction, and osteoinduction4.
Osteoconductive scaffolds create an environment permissive for the proliferation of bone cells, which fills the bone defect10. Calcium phosphate cements (CPCs) have a composition similar to the mineral phase of native bone, and have been used as bone substitutes in the last decades15. Hydroxiapatite and tricalcium phosphates are among the most used of these cements, and they have proved their value in several clinical applications6. However, CPCs have some limitations, related to poor mechanical properties and mainly to lack of osteoinductive and angiogenic activities. The first limitation can be dealt with by further modification of the biomaterial. To compensate for the lack of osteoinduction and angiogenesis, CPCs have been preloaded with cells.
The combination of adult stem cells with biomaterials has introduced new perspectives on the optimization of tissue repair protocols. Differentiated cells or stem cells may be used, and mesenchymal stem cells are among the most extensively studied biological elements in tissue engineering7. The plasticity and ease of collecting and ex vivo culturing of adipose-derived stem cells (ASCs) open wide possibilities of use in regenerative therapy2. This study aimed to evaluate the process of bone repair in a rat femoral defect model, using modified α-tricalcium phosphate (α-TCP) scaffolds and a commercially available biomaterial (absorbable gelatin sponge, GS) associated with allogeneic ASCs. Results were evaluated by histological and histomorphometric assessments of bone repair.