Comparison of the healing process in plated and non-plated fractures of the mandible in rats.

We compared the healing process of plated and non-plated fractures. The mandibles of 72 male Wistar rats were fractured and more either plated or not plated (n = 36 in each group). The healing process of the two conditions was studied histologically and immunohistochemically using a specific antibody to bone morphogenetic protein-2 (BMP-2). The results showed that the healing process in the plated group was delayed by one week compared with the non-plated group. Trauma to the surrounding soft tissues affected the healing process. BMP-2 was expressed at all stages in both groups. We conclude that the healing process is disturbed by the fixing of a plate; that periosteum is one of the main sources of osteogenic cells; and that BMP-2 is an important regulator of morphogenesis.