Tissue-engineered composites of bone and cartilage for mandible condylar reconstruction

Purpose: This study evaluated thr feasibility of creating a tissue-engineer ed adult human mandible condyle composite of bone and cartilage. Materials and Methods: A polymer template composed of polyglycolic acid (PG A) and polylactic acid (PLA), and formed in the shape of the human mandible condyle, was seeded with osteoblasts isolated from a bovine periosteum sus pended in calcium alginate, Chondrocytes isolated from the same calf suspen ded in 30% pluronic were then "painted" onto the articular surface of the s caffold, and it was then implanted into subcutaneous pockets on the: dorsum of athymic mice. Animals were divided into 3 groups: group I (n = 6) recei ved a PGA/PLA scaffold saturated with hydrogels nor containing cells; group II (n = 6) received scaffolds seeded with both cell types suspended in sal ine rather than hydrogels; and group III (n = 6) received scaffolds seeded with both cell types suspended in hydrogel composites. Constructs were harv ested after 12 weeks and evaluated grossly and microscopically by using his tologic stains. Results: In group I, the constructs formed a small mass without evidence of new bone or cartilage. In group II, the constructs were small and irregula r. Microscopically they contained scattered islands of bone and cartilage, All specimens in group III retained their original condylar shape and were quite firm. Microscopic evaluation indicated trabecular hone interfacing wi th hyaline cartilage on the articulating surface. Conclusion: These findings show that the composites of bone and cartilage c an be engineered to serve as condylar substitutes. The interdigitation of b one and cartilage at their interface is similar to the normal interface of these composite tissues seen in articulating joints. (C) 2001 American Asso ciation of Oral and Maxillofacial Surgeons.