THE EFFECT OF LOCAL X-RAY IRRADIATION UPON THE TEETH AND SURROUNDING TISSUES IN YOUNG AXOLOTLS (SIREDON MEXICANUM)

¹ Department of Anatomy, University of Maryland, School of Medicine, Baltimore, Md.

The teeth in the lower jaws of young axolotls (age 20 and 60 days after hatching) were irradiated with 2000 to 4000 r. On the day of treatment, some teeth were present. Animals which were irradiated 60 days after hatching had well-developed teeth.

The enamel epithelium disappeared in the treated teeth, and mitotic activity was completely suppressed in the surrounding tissue. Thirty-four days after irradiation of 20-day-old axolotls with 4000 r and 43 days after irradiation of 60-day-old axolotls with 3000 r, only small remnants of teeth were observed. About 15 days later, all remnants of the teeth had disappeared.

The formation of new teeth was never observed following the disappearance of the irradiated teeth, even one year after irradiation.

The mechanisms of tooth formation and tooth maintenance are permanently destroyed by 2000 to 4000 r doses of x-ray irradiation.