The susceptibility to experimental dental caries of rats from a strain with totally or partially missing enamel

Abstract

Rats from a strain in which many of the offspring have totally or almost completely missing enamel on their incisors and molars were used in two experiments to study the susceptibility of this strain to experimental dental caries. The rats with defective enamel tended to develop a low level of caries activity when fed Harvard semi-purified diet 2700, but a relatively high caries activity when fed Keyes and Jordan's diet 2000 which contains finely powdered sucrose and several natural food items. The rats of this strain with normal enamel had lower dental caries incidences when fed either diet 2700 or diet 2000 than rats of the strain which had defective enamel. Both the normal rats and those with abnormal or missing enamel appeared to have an adequate microbial flora for the development of carious lesions without the external provision of flora from caries-active rats. Some increase in caries activity was observed among the rats fed diet 2700 when they were caged with rats of the mutant albino strain with actively progressing carious lesions.