Experimental mandibular fracture: studies on bone repair and remodellation.

An experimental mandibular fracture model was developed in Sprague-Dawley rats. Healing and remodellation were studied using routine histology, microradiography and incorporation of tetracycline and lead acetate. Bone healing after fracture started by outgrowth of bone trabeculae from the periosteum and from marrow spaces in the mandibular corpus and coronoid process. Stabile fracture healing was seen after 14-16 days, which correlated to the time when bone trabeculae were seen to cross the fracture diastasis morphologically. Formation of reparative bone was produced by direct formation of bone trabeculae but also via formation of a chondroid tissue which was later resorbed and replaced by bone.