The Effect of Manganese Chloride on Amelogenesis

Abstract

The effect of manganese chloride on the amelogenesis of the incisors was studied in groups of rats, guinea pigs, and hamsters. The experimental animals received subcutaneous injections of manganese chloride, and the control animals were injected with sodium chloride solutions or remained untreated. The erupting incisors were observed periodically for the appearance in the oral cavity of any defects. Only in respect to the rats were sections prepared for a histologic examination. The histologic and clinical studies revealed that defects developed in 100% of the manganese chloride-treated rats. The hypoplastic enamel lesions observed clinically made their appearance in the oral cavity between the 35th and 50th days postinjection. No morphogenic alterations occurred. Hypoplastic enamel defects became evident clinically in the guinea pig incisors between the 56th and 73rd days postinjection. These faults developed in 100% of the surviving animals. Only 4 of the upper incisors remained free from hypoplastic damage. However, all the incisors exhibited a dual grooving. These grooves manifested a disturbance of morphogenesis. In each instance, the hypoplastic pitting developed in relation to the grooves. Amelogenesis in the hamsters was unaffected by the administration of manganese chloride.