Dental development and microstructure of bamboo rat incisors

Abstract

Bone adapts to habitual loads by remodeling to resist stresses that would otherwise break it. The question of whether the same holds for teeth, however, remains unanswered. We might expect species with ever-growing dentitions to alter enamel histology in response to diet. In this study we fed bamboo rats (Rhizomys sinensis) different foods to assess effects on enamel microstructure. Results indicate that gnawing fracture-resistant items (i.e., bamboo) produces substantively different dental microstructures than does eating less mechanically-challenging ones (i.e., potato). Bamboo induces a structured, anisotropic pattern of rods that strengthens incisor enamel, whereas potato produces less structured, weaker enamel. Blood tests suggest that these differences are not related to nutrient variation. Rather, these ever-growing teeth evidently require a specific mechanical environment to develop normal dental microstructure.