Microscopical Study of Caries of Rats' Teeth

Abstract

Albino rats fed 31 days on a Hoppert, Weber and Caniff diet showed no evidence of gross caries. Ground histologic sections 0.7-0.9 mm. thick showed that 85% of 285 fissures contained plugs of soft, brown fibrous material, assumed from its appearance to be impacted food. When caries occurred it attacked the enamel walls of the fissure close to but not quite at its apex and extended laterally towards the pulp horns undermining the cusps with subsequent fracture. In spite of the corn particle diet and violence of grinding the sections, there was initial fracturing in only one instance. The teeth of the albino rat on a Hoppert, Weber and Caniff diet do not fracture unless the cusps are first undermined by caries.