THE CURATIVE ACTION OF TOCOPHEROL AND OF PROTEIN UPON THE INCISOR TEETH OF VITAMIN E-DEPLETED 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 maintained on a vitamin E-free low-protein diet for 30 or 40 days, by which time all their upper incisor teeth were white. They were then divided into 3 groups.

2. The enamel organs of the group kept on the diet for up to 80 days showed marked degeneration and the iron-containing granules of the ameloblasts had disappeared by 30 days. All had positive dialuric acid hemolysis tests.

3. A second group was maintained on the vitamin E-free diet but was given 3 mg. of tocopherol daily for up to 80 days. The dialuric acid tests became negative after 10 days and the incisal pigment reappeared on an average of 42 days later. Iron was redeposited in the ameloblasts 10 days after dosage was started, but the morphologic recovery of the enamel organ was much slower. The outer enamel epithelium recovered first and even by 80 days the ameloblasts at the incisal end of the tooth were not completely normal.

4. A third group of rats were transferred to a vitamin E-free diet with a raised protein content for up to 80 days. The dialuric acid test remained positive throughout, but incisal pigment reappeared on an average of 47 days after the change of diet. The recovery of the enamel organ was exactly the same as in the group of rats dosed with tocopherol. Under these experimental conditions, extra dietary protein was just as adequate as tocopherol as a curative agent for the teeth.

5. It is suggested that the outer enamel epithelium has an organizing effect on the ameloblasts and is essential for their recovery from various insults. The ameloblasts at the incisal end of the tooth appear to have no function, since normal teeth can be produced in their absence.