Induction of cartilage and bone formation by cells from explants of various oral tissues in vitro.

Cells with both osteogenic and chondrogenic capabilities from various connective tissues, dental pulp, periodontal ligament, bone marrow, muscle and subcutaneous connective tissues of the rat were investigated by using either mineralized or demineralized bone and dentin matrix in vitro. After 28 days of the cell culture, explant cells were examined histologically. Bone and cartilage formations were assessed by counting their numbers in serial sections. Induction of cartilage was occurred only in muscle. New bone formation was occurred most frequently in dental pulp, followed in order by bone marrow and periodontal ligament. These results suggest that osteogenic cells, dental pulp, bone marrow stromal cells, and periodontal ligament can not response to inductive stimuli such as the bone morphogenetic protein, BMP.