Developmental arrest of tooth bud after correction of mandibular fracture.

A case of multiple fractures of the mandible following a car accident in a five-year-old patient is reported. The fracture line passed distal to the first molar tooth bud. The fracture was treated by wire osteosynthesis and skeletal fixation. During the ensuing 18 months, a gradual arrest of the development of the first molar tooth bud was radiologically observed. The eruption process had not been disturbed, and the tooth erupted at the age of 6 1/2 years. Since the distal root had completely failed to develop and the mesial roots showed a diminished size, the tooth was extracted. Histopathological examination revealed disturbed dentin apposition, there was almost complete obliteration of the pulp chamber by globular dentin, and evidence of root resorption.