Biological Organization of Hydroxyapatite Crystallites into a Fibrous Continuum Toughens and Controls Anisotropy in Human Enamel

摘要: Enamel forms the outer surface of teeth, which are complex shape and loaded in a multitude ways during function. has previously been assumed to be formed from discrete rods markedly aniostropic, but marked anisotropy might expected lead frequent fracture. Since fracture is not observed, we measured enamel organization using histology, imaging, mechanics modalities, compared with crystalline hydroxyapatite (Hap), its major component. was approximately three times tougher than geologic Hap, demonstrating critical importance biological manufacturing. Only modest levels were discerned; rather, our measurements suggest that composite ceramic crystallites oriented three-dimensional continuum. Geologic apatite crystals much harder enamel, suggesting inclusion contaminants, such as protein, influences properties enamel. Based on findings, ...