CHEN Bin, CHENG Zidong, LIN Shiyun, FANG Zhongqi, NIE Shuyan, JIANG Zhiping
(College of Aerospace Engineering, Chongqing University, Chongqing 400044, China)

Abstract: As a natural bioceramic composite, cheek tooth possesses hierarchical microstructure. It consists first of hydroxyapatite layers and collagen protein matter, which make up a laminated microstructure. Further, the hydroxyapatite layers are composed of hydroxyapatite sheets. The hydroxyapatite sheets in different layers have different orientations, which compose a crossed microstructure. The two-level models of the tooth are respectively built for investigating the fracture energy of the laminated microstructure and the maximum pullout force of the crossed microstructure. It is revealed that the laminated microstructure increases the fracture energy of the tooth and the fiber-crossed microstructure enhances the maximum pullout force of the fiber sheets. The analytical result about the maximum pullout force of the crossed microstructure is experimentally validated. It can be concluded that the excellent microstructures in different hierarchies of the tooth endow the tooth with high-performance mechanical properties.

Key words: cheek tooth; hydroxyapatite; laminated microstructure; crossed microstructure; mechanical properties.