THE RELATIONSHIP BETWEEN THE HISTOLOGY OF THE THYROID AND THE SALIVARY GLANDS AND THE INCIDENCE OF DENTAL CARIES IN THE RAT

¹ Indiana University School of Dentistry, Bloomington and Indianapolis, Ind.

The administration of single doses of 100, 250, 500, and 750 µc of radioactive iodine (I¹³¹) to 4 groups of weanling rats produced a graded increase in their dental caries experience. Histologic study of the thyroid glands from the various groups revealed that 100 µc of I¹³¹ was without significant effect upon the thyroid gland, whereas each higher dosage of I¹³¹ produced a greater and more pronounced atrophy. Thus, a direct relationship between thyroid function and dental caries experience in the rat seems apparent. Furthermore, histologic study of the submaxillary glands of the animals in the various groups revealed a progressive nonfunctioning, atrophic appearance with increasing concentrations of radioactive iodine. From these results it appears that loss of thyroid function may be intimately associated with loss of salivary gland function. The salivary glands then are considered as possible intermediates in a thyroid gland-dental caries relationship in the rat.