Effect of dietary consistency and incisor trimming on the morphology of the craniofacial complex in the rat (Rattus norvegicus). I. The nasal septum.

The purpose of this investigation was to examine histological changes in nasal septal cartilage due to alteration of dietary consistency and loss of incisor function. Sixteen female, weanling Sprague-Dawley rats (Rattus norvegicus), were subjected to one of the following feeding treatments: control rats (n = 7) received a standard pelleted chow; experimental rats (n = 9) received meal sufficient in calories and nutrients to sustain increases in body weight. The maxillary incisors of experimental rats were trimmed to the level of the gingiva on alternate days to minimize anterior occlusal loading associated with nonfeeding behaviors. Rats were killed at 13 weeks, the nasal septa prepared for histology and the dimensions of septal cartilage and mucoperichondrium were measured. Quantitative and qualitative comparisons between control and experimental rats revealed a lack of significant differences in size, shape and thickness of septal cartilage and mucoperichondrium. The results of this study provide support for the concept that postnatal growth of primary cranial cartilages is largely independent of extrinsic biomechanical forces.