the effect of unerupted permanent tooth crowns on the distribution of masticatory stress in childrenunerupted永久牙冠的影响在儿童咀嚼压力的分布.pdf

The Effect of Unerupted Permanent Tooth Crowns on the Distribution of Masticatory Stress in Children 1,2 3 2,4 Ashley S. Hammond *, Elizabeth R. Dumont , Robert C. McCarthy 1 Department of Pathology and Anatomical Sciences, University of Missouri School of Medicine, Columbia, Missouri, United States of America, 2 Department of Anthropology, Florida Atlantic University, Boca Raton, Florida, United States of America, 3 Department of Organismal and Evolutionary Biology, University of Massachusetts-Amherst, Amherst, Massachusetts, United States of America, 4 Department of Anthropology, University at Albany, Albany, New York, United States of America Abstract Human mothers wean their children from breast milk at an earlier developmental stage than do ape mothers, resulting in human children chewing solid and semi-solid foods using the deciduous dentition. Mechanical forces generated by chewing solid foods during the post-weaning period travel through not only the deciduous teeth, but also the enamel caps of the developing permanent teeth within the maxilla and mandible, which are not present in the adult face. The effects of mechanical stress propagating through these very stiff structures have yet to be examined. Based on a heuristic model, we predicted that the enamel of the embedded developing teeth would act to reduce stresses in the surrounding bony elements of the juvenile face. We tested this hypothesis by simulating occlusal loading in a finite element (FE) model of a child’s cranium with a complete set of deciduous teeth and the first permanent molars embedded in the bony crypt in the maxilla. We modeled bone and enamel with appropriate material properties and assessed the effe