TISSUE REACTIONS IN EXPERIMENTAL TOOTH FRACTURE

¹ Dept. of Anatomy, College of Dentistry, New York University, New York, N. Y.

1. The tissue reactions of deciduous molars, which were experimentally fractured, and surrounding tissues of dogs were observed.

2. The reaction of the coronal part of the pulp exposed to the oral fluids by fracture is severe; necrosis and resorption of the tissue occurrs.

3. The coronal part of the pulp which is protected by an epithelial overgrowth derived from the gingiva shows moderate round cell infiltration and fibrous replacement. The apical part of the pulp remains relatively normal.

4. The reaction which occurs in a fracture appears to be dependent on 2 factors: 1, The proximity to the oral cavity and 2, the relation of the fragment surfaces to each other.

5. Coronal fractures containing round cells and necrotic tissue do not repair as rapidly as apical fractures not complicated by inflammatory changes.

6. Fragments in apposition and in proper alignment more nearly approximate a characteristic bone repair than those in which the fragments do not meet these conditions. In these latter situations, only a fibrous union occurs.

7. In some respects, the reactions observed in a fracture of the root are similar to those observed in bone; calcific replacement, however, is not as rapid nor as extensive as is the case in the repair of a fracture of bone.