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Marsico C, Grimm JR, Renteria C, Guillen DP, Tang K, Nikitin V, Arola DD. Characterizing the microstructures of mammalian enamel by synchrotron phase contrast microCT. Acta Biomater 2024; 178:208-220. [PMID: 38428512 DOI: 10.1016/j.actbio.2024.02.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 02/08/2024] [Accepted: 02/23/2024] [Indexed: 03/03/2024]
Abstract
The enamel of mammalian teeth is a highly mineralized tissue that must endure a lifetime of cyclic contact and is inspiring the development of next-generation engineering materials. Attempts to implement enamel-inspired structures in synthetic materials have had limited success, largely due to the absence of a detailed understanding of its microstructure. The present work used synchrotron phase-contrast microCT imaging to evaluate the three-dimensional microstructure of enamel from four mammals including Lion, Gray Wolf, Snow Leopard, and Black Bear. Quantitative results of image analysis revealed that the decussation pattern of enamel consists of discrete diazone (D) and parazone (P) bands of rods organized with stacking arrangement of D+/P/D-/P in all mammals evaluated; the D+ and D- refer to distinct diazone bands with juxtaposed rod orientations from the reference plane. Furthermore, the rod orientations in the bands can be described in terms of two principal angles, defined here as the pitch and yaw. While the pitch angle increases from the outer enamel to a maximum (up to ≈ 40°) near the dentin enamel junction, minimal spatial variations are observed in yaw across the enamel thickness. There are clear differences in the decussation parameters of enamel across species that are interpreted here with respect to the structural demands placed on their teeth. The rod pitch and band width of enamel are identified as important design parameters and appear to be correlated with the bite force quotient of the four mammals evaluated. STATEMENT OF SIGNIFICANCE: The multi-functionality of tooth enamel requires both hardness and resistance to fracture, properties that are generally mutually exclusive. Ubiquitous to all mammalian teeth, the enamel is expected to have undergone adaptations in microstructure to accommodate the differences in diet, body size and bite force across animals. For the first time, we compare the complex three-dimensional microstructure of enamel from teeth of multiple mammalian species using synchrotron micro-computed tomography. The findings provide new understanding of the "design" of mammalian enamel microstructures, as well as how specific parameters associated with the decussation of rods appear to be engineered to modulate its fracture resistance.
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Affiliation(s)
- C Marsico
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA; Materials Science and Engineering Department, Idaho National Laboratory, Idaho Falls, ID, USA
| | - J R Grimm
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA; Physical and Computational Science Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - C Renteria
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA; Department of Oral Health Sciences, University of Washington, Seattle, WA, USA
| | - D P Guillen
- Materials Science and Engineering Department, Idaho National Laboratory, Idaho Falls, ID, USA
| | - K Tang
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA
| | - V Nikitin
- Department of Chemistry, Argonne National Laboratory, Lemond, IL, USA
| | - D D Arola
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA; Department of Restorative Dentistry, School of Dentistry, University of Washington, Seattle, WA, USA; Department of Mechanical Engineering, University of Washington, Seattle, WA, USA.
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Tooth Wear and Tribological Investigations in Dentistry. Appl Bionics Biomech 2022; 2022:2861197. [PMID: 35721235 PMCID: PMC9203238 DOI: 10.1155/2022/2861197] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 05/20/2022] [Accepted: 05/23/2022] [Indexed: 11/25/2022] Open
Abstract
Dental or tooth wear is a physiological process in the life cycle of teeth. Loss of the occlusal surface may cause excessive tooth wear. Several factors may contribute to tooth wear with different intensities and duration in the oral cavity. The oral cavity is generally compared to a tribological system to determine the various types of wear between teeth and restorative materials and assess the amount of dental wear. However, it is challenging to investigate in vitro and in vivo wear owing to the complexity of tooth wear; thus, a clear correlation between in vitro and in vivo data could not be established. This review is aimed at providing an insight into the etiology of tooth wear and tribological investigations in dentistry.
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Peng J, Xiao H, Lei L, Yang D, Zheng J, Zhou Z. Heterogeneous hardening of enamel surface by occlusal loading: Effect of nanofiber orientation. J Mech Behav Biomed Mater 2022; 130:105221. [DOI: 10.1016/j.jmbbm.2022.105221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 03/27/2022] [Accepted: 04/02/2022] [Indexed: 11/30/2022]
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Meng Y, Xu J, Ma L, Jin Z, Prakash B, Ma T, Wang W. A review of advances in tribology in 2020–2021. FRICTION 2022; 10:1443-1595. [PMCID: PMC9552739 DOI: 10.1007/s40544-022-0685-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 08/22/2022] [Indexed: 07/22/2023]
Abstract
Around 1,000 peer-reviewed papers were selected from 3,450 articles published during 2020–2021, and reviewed as the representative advances in tribology research worldwide. The survey highlights the development in lubrication, wear and surface engineering, biotribology, high temperature tribology, and computational tribology, providing a show window of the achievements of recent fundamental and application researches in the field of tribology.
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Affiliation(s)
- Yonggang Meng
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing, 100084 China
| | - Jun Xu
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing, 100084 China
| | - Liran Ma
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing, 100084 China
| | - Zhongmin Jin
- School of Mechanical Engineering, Southwest Jiaotong University, Chengdu, 610031 China
- School of Mechanical Engineering, University of Leeds, Leeds, LS2 9JT UK
| | - Braham Prakash
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing, 100084 China
| | - Tianbao Ma
- State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing, 100084 China
| | - Wenzhong Wang
- School of Mechanical and Vehicle Engineering, Beijing Institute of Technology, Beijing, 100082 China
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