Meeting Abstract

33.4  Wednesday, Jan. 5  Root Surface Area in Relation to Diet in Rodents: A CT Method for Evaluating Tooth Surface Area SELF, CJ*; PAYNE, AA; University of Washington, Seattle; University of Washington, Seattle cjself@uw.edu

Occlusal force produced during chewing is transmitted to alveolar bone via the tooth roots and the periodontal ligament. As the tooth root participates in load transfer and provides an attachment area for the PDL it is likely a reliable indicator for habitual loads. Studies have indicated that diets consisting of hard foods require a larger bite force to process. MicroCT scans were used to obtain root surface dimensions for four cricetid rodent species representing seed herbivores (Phyllotis darwini), vegetation herbivores (Calomys callosus, Reithrodon typicus) and insectivores (Oxymycterus rufus). It was hypothesized that hard food processing individuals, the seed herbivores, would have the highest bite force, while grass processing individuals would have the lowest. The five mandibles from each species were CT scanned at nine micron resolution and each tooth in the left post-canine tooth row was digitally isolated from the surrounding alveolar bone. Body size was controlled using the geometric mean of six cranial measurements. Root surface area of the combined molar tooth row was compared between dietary groups. Results indicate seed eating rodents have the highest root surface area, supporting the stated hypothesis. The insectivore group had the next highest root surface area. Among the vegetation herbivores one species (Calomys) had the smallest root surface area, as expected. However, Reithrodon showed a larger root area than the insectivores. One possibility for the discrepancy is that body size controls may not have been sufficient. Alternatively, Reithrodon has particularly high-crowned teeth, when compared to the rest of the sample, indicating a possible relationship between crown size and root area.