THE INFLUENCE OF DIETS CONTAINING FATS WITH HIGHLY UNSATURATED FATTY ACIDS UPON THE MAXILLARY INCISOR TEETH OF RATS

¹ Joint Dental Research Unit of the South African Council for Scientific and Industrial Research and the University of the Witwatersrand, Johannesburg, South Africa

1. Young rats were put on vitamin E-free diets containing either cod-liver oil or hake-liver oil, and were sacrificed at intervals. The enamel organs of the upper incisor teeth were examined histologically and the color of the teeth noted.

2. Using a diet containing cod-liver oil, histologic changes like those described by Irving¹¹ were obtained and the teeth became white, both changes being averted by -tocopherol dosage. The changes differed in some respects from those described by Pindborg^{17, 18} and it is suggested that the animals in his experiments were suffering from a more chronic form of vitamin E deficiency.

3. The histologic changes using hake-liver oil were considerably more extreme than those caused by the cod-liver oil diet, and neither the microscopic changes nor the whitening of the teeth was prevented by -tocopherol dosage.

4. With both types of diet, the affected ameloblasts were on the incisal side of the granular ameloblasts, the enamel organ on the formative side of these cells being unchanged. This contrasts with the findings in other deficiencies, when other parts of the enamel organ are affected.

5. It is concluded that the enamel organ of continuously erupting teeth varies from part to part in its sensitivities to toxic substances and requirements of essential nutrients, these variations corresponding with the differing physiologic functions of the parts concerned.