Oral Effects of Injected Strontium 90

¹ Department of Dental Medicine, Guy's Hospital, London, England

Weanling rabbits injected with 600 µc/kg Sr⁹⁰ showed dental changes that included arrest of growth in length and of eruption of the cheek teeth, diminished diameter of the incisors, and replacement of most of the pulps with defective dentin. Arrest of bone apposition near the teeth was followed in a few months by pleomorphic osteoblastic proliferation, which, within 6 months of injection, was succeeded by multifocal osteosarcoma. Histologic changes were correlated with dose rates and accumulated doses obtained from the contralateral jaws by Owen. Adult rabbits of less than 2 years of age injected at the same dose level showed similar but slower effects, but those of more than 3 years of age showed less disturbance and considerable recovery of dental growth. In adult rabbits, the same injected dose produced much higher dose rates, enormous accumulated doses in the mandibles, and teeth with severe damage to bone, but delayed proliferative changes and incidence of osteosarcoma.