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Diez-Escudero A, Espanol M, Ginebra MP. High-aspect-ratio nanostructured hydroxyapatite: towards new functionalities for a classical material. Chem Sci 2023; 15:55-76. [PMID: 38131070 PMCID: PMC10732134 DOI: 10.1039/d3sc05344j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 11/20/2023] [Indexed: 12/23/2023] Open
Abstract
Hydroxyapatite-based materials have been widely used in countless applications, such as bone regeneration, catalysis, air and water purification or protein separation. Recently, much interest has been given to controlling the aspect ratio of hydroxyapatite crystals from bulk samples. The ability to exert control over the aspect ratio may revolutionize the applications of these materials towards new functional materials. Controlling the shape, size and orientation of HA crystals allows obtaining high aspect ratio structures, improving several key properties of HA materials such as molecule adsorption, ion exchange, catalytic reactions, and even overcoming the well-known brittleness of ceramic materials. Regulating the morphogenesis of HA crystals to form elongated oriented fibres has led to flexible inorganic synthetic sponges, aerogels, membranes, papers, among others, with applications in sustainability, energy and catalysis, and especially in the biomedical field.
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Affiliation(s)
- Anna Diez-Escudero
- Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Engineering, Universitat Politècnica de Catalunya (UPC) Av. Eduard Maristany 16 08019 Barcelona Spain
- Barcelona Research Center in Multiscale Science and Engineering, Universitat Politècnica de Catalunya (UPC) Av. Eduard Maristany 16 08019 Barcelona Spain
| | - Montserrat Espanol
- Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Engineering, Universitat Politècnica de Catalunya (UPC) Av. Eduard Maristany 16 08019 Barcelona Spain
- Barcelona Research Center in Multiscale Science and Engineering, Universitat Politècnica de Catalunya (UPC) Av. Eduard Maristany 16 08019 Barcelona Spain
| | - Maria-Pau Ginebra
- Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Engineering, Universitat Politècnica de Catalunya (UPC) Av. Eduard Maristany 16 08019 Barcelona Spain
- Barcelona Research Center in Multiscale Science and Engineering, Universitat Politècnica de Catalunya (UPC) Av. Eduard Maristany 16 08019 Barcelona Spain
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology Baldiri Reixac 10-12 08028 Barcelona Spain
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2
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Towle I, Loho T, Salem AS, Berthaume MA, Loch C. Variation in enamel mechanical properties throughout the crown in catarrhine primates. J Hum Evol 2023; 182:103413. [PMID: 37562101 DOI: 10.1016/j.jhevol.2023.103413] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 07/05/2023] [Accepted: 07/08/2023] [Indexed: 08/12/2023]
Abstract
Enamel mechanical properties vary across molar crowns, but the relationship among mechanical properties, tooth function, and phylogeny are not well understood. Fifteen primate lower molars representing fourteen taxa (catarrhine, n = 13; platyrrhine, n = 1) were sectioned in the lingual-buccal plane through the mesial cusps. Gradients of enamel mechanical properties, specifically hardness and elastic modulus, were quantified using nanoindentation from inner (near the enamel-dentine junction), through middle, to outer enamel (near the outer enamel surface) at five positions (buccal lateral, buccal cuspal, occlusal middle, lingual cuspal, lingual lateral). Cuspal positions had higher mechanical property values than lateral positions. Middle enamel had higher mean hardness and elastic modulus values than inner and outer locations in all five crown positions. Functionally, the thicker-enameled buccal cusps of lower molars did not show evidence of increased resistance to failure; instead, lingual cusps-which show higher rates of fracture-had higher average mechanical property values, with no significant differences observed between sides. Preliminary phylogenetic results suggest there is relatively little phylogenetic signal in gradients of mechanical properties through the enamel or across the crown. There appears to be common mechanical property patterns across molar crowns in Catarrhini and potentially among primates more broadly. These results may allow more precise interpretations of dental biomechanics and processes resulting in mechanical failure of enamel in primates, such as wear and fracture.
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Affiliation(s)
- Ian Towle
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin 9054, New Zealand.
| | - Thomas Loho
- Faculty of Engineering, The University of Auckland, Auckland 1010, New Zealand
| | - Amira Samir Salem
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin 9054, New Zealand
| | - Michael A Berthaume
- Division of Mechanical Engineering and Design, London South Bank University, London SE1 0AA, UK
| | - Carolina Loch
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin 9054, New Zealand
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3
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Kruzic JJ, Hoffman M, Arsecularatne JA. Fatigue and wear of human tooth enamel: A review. J Mech Behav Biomed Mater 2023; 138:105574. [PMID: 36473402 DOI: 10.1016/j.jmbbm.2022.105574] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 09/14/2022] [Accepted: 11/15/2022] [Indexed: 11/21/2022]
Abstract
Human tooth enamel must withstand the cyclic contact forces, wear, and corrosion processes involved with typical oral functions. Furthermore, unlike other human tissues, dental enamel does not have a significant capacity for healing or self-repair and thus the longevity of natural teeth in the oral environment depends to a large degree on the fatigue and wear properties of enamel. The purpose of this review is to provide an overview of our understanding of the fatigue and wear mechanisms of human enamel and how they relate to in vivo observations of tooth damage in the complex oral environment. A key finding of this review is that fatigue and wear processes are closely related. For example, the presence of abrasive wear particles significantly lowers the forces needed to initiate contact fatigue cracking while subsurface fatigue crack propagation drives key delamination wear mechanisms during attrition or attrition-corrosion of enamel. Furthermore, this review seeks to bring a materials science and mechanical engineering perspective to fatigue and wear phenomena. In this regard, we see developing a mechanistic description of fatigue and wear, and understanding the interconnectivity of the processes, as essential for successfully modelling enamel fatigue and wear damage and developing strategies and treatments to improve the longevity of our natural teeth. Furthermore, we anticipate that this review will stimulate ideas for extending the lifetime of the natural tooth structure and will help highlight where our understanding is too limited and where additional research into fatigue and wear of human tooth enamel is warranted.
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Affiliation(s)
- Jamie J Kruzic
- School of Mechanical and Manufacturing Engineering, University of New South Wales (UNSW Sydney), Sydney NSW 2052, Australia.
| | - Mark Hoffman
- School of Engineering, University of Newcastle, Callaghan NSW 2308, Australia; School of Materials Science and Engineering, University of New South Wales (UNSW Sydney), Sydney NSW 2052, Australia
| | - Joseph A Arsecularatne
- School of Mechanical and Manufacturing Engineering, University of New South Wales (UNSW Sydney), Sydney NSW 2052, Australia
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4
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Liu S, Xu Y, An B, Zhang D. Interaction of rod decussation and crack growth in enamel. Comput Methods Biomech Biomed Engin 2022; 26:700-709. [PMID: 35815376 DOI: 10.1080/10255842.2022.2084333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Enamel possesses ingenious hierarchical structure that gives rise to superior fracture resistance. Despite considerable efforts devoted to characterization of fracture behavior of enamel, the role of rod decussation in fracture of enamel is largely unknown. In this study, the features of rod decussation in the inner enamel are experimentally identified, and analyses of crack growth in enamel are carried out using a micromechanical model of enamel, in which the structural features of the outer enamel and rod decussation of the inner enamel are incorporated. We carry out calculations within a framework based on the extended finite element method, and the crack growth and crack path selection are natural outcomes of imposed loading. We show that crack deflection in enamel is controlled by rod decussation. For crack growth in the parazone, the crack path is oriented along the axis of enamel rods, leading to gross crack deflection. The microstructure of inner enamel with intermediate inclination angle enables multiple crack deflections, giving rise to enhanced toughness. For crack growth in the diazone, the transition in orientation of crack deflection occurs as inclination angle increases. The relatively straight crack path emerges in the case of the microstructure of enamel with intermediate inclination angle, leading to weak fracture resistance. It is further found that compared with the diazone, the gross crack deflection in the parazone provides greater contribution to fracture resistance of enamel. The findings of this study provide a good mechanistic understanding of the role of rod decussation in enamel.
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Affiliation(s)
- Siyong Liu
- School of Mechanics and Engineering Science, Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai, China.,Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai, China
| | - Yuanzhi Xu
- Department of Stomatology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, 200072, P R China
| | - Bingbing An
- School of Mechanics and Engineering Science, Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai, China.,Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai, China
| | - Dongsheng Zhang
- School of Mechanics and Engineering Science, Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai, China.,Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai, China
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5
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The effect of aging on the wear performance of monolithic zirconia. Dent Mater 2022; 38:e136-e146. [DOI: 10.1016/j.dental.2022.04.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 03/06/2022] [Accepted: 04/01/2022] [Indexed: 11/24/2022]
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6
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Hubbard MJ, Mangum JE, Perez VA, Williams R. A Breakthrough in Understanding the Pathogenesis of Molar Hypomineralisation: The Mineralisation-Poisoning Model. Front Physiol 2022; 12:802833. [PMID: 34992550 PMCID: PMC8724775 DOI: 10.3389/fphys.2021.802833] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 11/26/2021] [Indexed: 11/13/2022] Open
Abstract
Popularly known as "chalky teeth", molar hypomineralisation (MH) affects over 1-in-5 children worldwide, triggering massive amounts of suffering from toothache and rapid decay. MH stems from childhood illness and so offers a medical-prevention avenue for improving oral and paediatric health. With a cross-sector translational research and education network (The D3 Group; thed3group.org) now highlighting this global health opportunity, aetiological understanding is urgently needed to enable better awareness, management and eventual prevention of MH. Causation and pathogenesis of "chalky enamel spots" (i.e., demarcated opacities, the defining pathology of MH) remain unclear despite 100 years of investigation. However, recent biochemical studies provided a pathomechanistic breakthrough by explaining several hallmarks of chalky opacities for the first time. This article outlines these findings in context of previous understanding and provides a working model for future investigations. The proposed pathomechanism, termed "mineralisation poisoning", involves localised exposure of immature enamel to serum albumin. Albumin binds to enamel-mineral crystals and blocks their growth, leading to chalky opacities with distinct borders. Being centred on extracellular fluid rather than enamel-forming cells as held by dogma, this localising pathomechanism invokes a new type of connection with childhood illness. These advances open a novel direction for research into pathogenesis and causation of MH, and offer prospects for better clinical management. Future research will require wide-ranging inputs that ideally should be coordinated through a worldwide translational network. We hope this breakthrough will ultimately lead to medical prevention of MH, prompting global health benefits including major reductions in childhood tooth decay.
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Affiliation(s)
- Michael J Hubbard
- Faculty of Medicine Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, Australia.,Department of Paediatrics, The University of Melbourne, Parkville, VIC, Australia.,Department of Pharmacology & Therapeutics, The University of Melbourne, Parkville, VIC, Australia.,Melbourne Dental School, The University of Melbourne, Parkville, VIC, Australia
| | - Jonathan E Mangum
- Department of Pharmacology & Therapeutics, The University of Melbourne, Parkville, VIC, Australia
| | - Vidal A Perez
- Department of Pharmacology & Therapeutics, The University of Melbourne, Parkville, VIC, Australia.,Department of Pediatric Stomatology, Faculty of Health Sciences, University of Talca, Talca, Chile
| | - Rebecca Williams
- Department of Pharmacology & Therapeutics, The University of Melbourne, Parkville, VIC, Australia.,Melbourne Dental School, The University of Melbourne, Parkville, VIC, Australia
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7
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Wang J, Liu Z, Ren B, Wang Q, Wu J, Yang N, Sui X, Li L, Li M, Zhang X, Li X, Wang B. Biomimetic mineralisation systems for in situ enamel restoration inspired by amelogenesis. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2021; 32:115. [PMID: 34455518 PMCID: PMC8403113 DOI: 10.1007/s10856-021-06583-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 07/05/2021] [Indexed: 05/28/2023]
Abstract
Caries and dental erosion are common oral diseases. Traditional treatments involve the mechanical removal of decay and filling but these methods are not suitable for cases involving large-scale enamel erosion, such as hypoplasia. To develop a noninvasive treatment, promoting remineralisation in the early stage of caries is of considerable clinical significance. Therefore, biomimetic mineralisation is an ideal approach for restoring enamel. Biomimetic mineralisation forms a new mineral layer that is tightly attached to the surface of the enamel. This review details the state-of-art achievements on the application of amelogenin and non-amelogenin, amorphous calcium phosphate, ions flow and other techniques in the biomimetic mineralisation of enamel. The ultimate goal of this review was to shed light on the requirements for enamel biomineralisation. Hence, herein, we summarise two strategies of biological minimisation systems for in situ enamel restoration inspired by amelogenesis that have been developed in recent years and compare their advantages and disadvantages.
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Affiliation(s)
- Jue Wang
- Department of Obsterics and Gynecology, The Second Hospital of Jilin University, Changchun, Jilin, China
- Department of Prosthodontics, Hospital of Stomatology, Jilin University, Changchun, Jilin, China
| | - Zhihui Liu
- Department of Prosthodontics, Hospital of Stomatology, Jilin University, Changchun, Jilin, China
| | - Bingyu Ren
- Department of Thyroid surgery, The Second Hospital of Jilin University, Changchun, Jilin, China
| | - Qian Wang
- Department of Prosthodontics, Hospital of Stomatology, Jilin University, Changchun, Jilin, China
| | - Jia Wu
- Department of Prosthodontics, Hospital of Stomatology, Jilin University, Changchun, Jilin, China
| | - Nan Yang
- Department of Prosthodontics, Hospital of Stomatology, Jilin University, Changchun, Jilin, China
| | - Xin Sui
- Department of Prosthodontics, Hospital of Stomatology, Jilin University, Changchun, Jilin, China
| | - Lingfeng Li
- Department of Prosthodontics, Hospital of Stomatology, Jilin University, Changchun, Jilin, China
| | - Meihui Li
- Department of Prosthodontics, Hospital of Stomatology, Jilin University, Changchun, Jilin, China
| | - Xiao Zhang
- Department of Prosthodontics, Hospital of Stomatology, Jilin University, Changchun, Jilin, China
| | - Xinyue Li
- Department of Prosthodontics, Hospital of Stomatology, Jilin University, Changchun, Jilin, China
| | - Bowei Wang
- Department of Obsterics and Gynecology, The Second Hospital of Jilin University, Changchun, Jilin, China.
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8
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Shape-preserving erosion controlled by the graded microarchitecture of shark tooth enameloid. Nat Commun 2020; 11:5971. [PMID: 33235202 PMCID: PMC7686312 DOI: 10.1038/s41467-020-19739-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 10/27/2020] [Indexed: 11/24/2022] Open
Abstract
The teeth of all vertebrates predominantly comprise the same materials, but their lifespans vary widely: in stark contrast to mammals, shark teeth are functional only for weeks, rather than decades, making lifelong durability largely irrelevant. However, their diets are diverse and often mechanically demanding, and as such, their teeth should maintain a functional morphology, even in the face of extremely high and potentially damaging contact stresses. Here, we reconcile the dilemma between the need for an operative tooth geometry and the unavoidable damage inherent to feeding on hard foods, demonstrating that the tooth cusps of Port Jackson sharks, hard-shelled prey specialists, possess unusual microarchitecture that controls tooth erosion in a way that maintains functional cusp shape. The graded architecture in the enameloid provokes a location-specific damage response, combining chipping of outer enameloid and smooth wear of inner enameloid to preserve an efficient shape for grasping hard prey. Our discovery provides experimental support for the dominant theory that multi-layered tooth enameloid facilitated evolutionary diversification of shark ecologies. Shark teeth have short lifespans yet can be subject to significant mechanical damage. Here, the authors report on a site-specific damage mechanism in shark teeth enameloid, which maintains tooth functional shape, providing experimental evidence that tooth architecture may have influenced the diversification of shark ecologies over evolution.
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9
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Deformation behavior of normal human enamel: A study by nanoindentation. J Mech Behav Biomed Mater 2020; 108:103799. [DOI: 10.1016/j.jmbbm.2020.103799] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 04/09/2020] [Accepted: 04/12/2020] [Indexed: 11/24/2022]
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10
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Wilmers J, Bargmann S. Nature's design solutions in dental enamel: Uniting high strength and extreme damage resistance. Acta Biomater 2020; 107:1-24. [PMID: 32087326 DOI: 10.1016/j.actbio.2020.02.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 02/07/2020] [Accepted: 02/12/2020] [Indexed: 02/06/2023]
Abstract
The most important demand of today's high-performance materials is to unite high strength with extreme fracture toughness. The combination of withstanding large forces (strength) and resistance to fracture (toughness), especially preventing catastrophic material failure by cracking, is of utmost importance when it comes to structural applications of these materials. However, these two properties are commonly found to be mutually exclusive: strong materials are brittle and tough materials are soft. In dental enamel, nature has combined both properties with outstanding success - despite a limited number of available constituents. Made up of brittle mineral crystals arranged in a sophisticated hierarchical microstructure, enamel exhibits high stiffness and excellent toughness. Different species exhibit a variety of structural adaptations on varying scales in their dental enamel which optimise not only fracture toughness, but also hardness and abrasion behaviour. Nature's materials still outperform their synthetic counterparts due to these complex structure-property relationships that are not yet fully understood. By analysing structure variations and the underlying mechanical mechanisms systematically, design principles which are the key for the development of advanced synthetic materials uniting high strength and toughness can be formulated. STATEMENT OF SIGNIFICANCE: Dental enamel is a hard protective tissue that combines high strength with an exceptional resistance to catastrophic fracture, properties that in classical materials are commonly found to be mutually exclusive. The biological material is able to outperform its synthetic counterparts due to a sophisticated hierarchical microstructure. Between different species, microstructural adaptations can vary significantly. In this contribution, the different types of dental enamel present in different species are reviewed and connections between microstructure and (mechanical) properties are drawn. By consolidating available information for various species and reviewing it from a materials science point of view, design principles for the development of advanced biomimetic materials uniting high strength and toughness can be formulated.
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11
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Zhang S, Liu Y, Shang J, Ujjaman Chudry MK, Zheng Y, Cai J, An B, Zhang D, Zheng R. Enamel-inspired materials design achieving balance of high stiffness and large energy dissipation. J Mech Behav Biomed Mater 2020; 103:103587. [PMID: 32090916 DOI: 10.1016/j.jmbbm.2019.103587] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 11/25/2019] [Accepted: 12/06/2019] [Indexed: 11/19/2022]
Abstract
Owing to the unique non-self-similar hierarchical microstructure, enamel achieves the balance of high stiffness and toughness, and in turn provides important ideas for the bio-inspired materials design. In this study, a multiscale numerical study has been conducted to investigate whether the property of high stiffness and large energy dissipation could be duplicated in engineering materials through certain material design principles. Motivated by the structure of enamel, the bio-inspired materials consisting of hard and soft phases were considered, and the designing parameters including the cross-sectional shape, volume fraction, and inclination angle of the reinforcement, and other three parameters related to the waviness of the reinforcement were taken into account. It was found that by employing the non-self-similar hierarchical structure, the designed composites exhibited the balance between stiffness and toughness, which has not been achieved in many engineering materials yet. Furthermore, the influences of the aforementioned designing parameters on the mechanical performance of the composites have been elucidated. The findings of this study have provided a guideline for designing bio-inspired composites achieving the balance between stiffness and toughness.
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Affiliation(s)
- Shuiqiang Zhang
- School of Engineering, Huzhou University, Huzhou, 313000, China.
| | - Yuying Liu
- School of Engineering, Huzhou University, Huzhou, 313000, China
| | - Jiangyinzi Shang
- Department of Orthopedics, Huashan Hospital, Fudan University, Shanghai, China
| | | | - Yuqing Zheng
- School of Engineering, Huzhou University, Huzhou, 313000, China
| | - Jiabin Cai
- School of Engineering, Huzhou University, Huzhou, 313000, China
| | - Bingbing An
- Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai, 200072, China; School of Mechanics and Engineering Science, Shanghai University, Shanghai, 200444, China
| | - Dongsheng Zhang
- Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai, 200072, China; School of Mechanics and Engineering Science, Shanghai University, Shanghai, 200444, China
| | - Ruizhe Zheng
- Shanghai Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200050, China
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12
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Yilmaz ED, Koldehoff J, Schneider GA. On the systematic documentation of the structural characteristics of bovine enamel: A critic to the protein sheath concept. Dent Mater 2018; 34:1518-1530. [DOI: 10.1016/j.dental.2018.06.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 05/24/2018] [Accepted: 06/07/2018] [Indexed: 11/28/2022]
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13
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DENG QIANG, ZONG ZHIFANG, NING ZHENWU, ZHENG JING, LIU JIANTAO, ZHOU ZHONGRONG. A COMPUTATIONAL STRATEGY TO EXAMINE THE PROFILE EFFECTS OF MICROPRISM REGIONS ON THE OVERALL ANISOTROPY OF HUMAN ENAMELS. J MECH MED BIOL 2018. [DOI: 10.1142/s0219519418500276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In this study, our attention is mainly on elaborating a computational strategy to effectively predict the influence of prism profiles on the overall anisotropic property of human enamels (HEs). At first, two distinct schemes are developed separately with the aid of the polynomial fitting technique and the general power functions to mathematically describe the practical irregular and simplified regular profiles of enamel prisms. Hereafter, two parametric piecewise formulas, which facilitate the definition of anisotropic material properties of finite elements at different locations and make the numerical simulation of HE microstructures consisting of irregularly shaped prisms feasible, are presented to describe the orientation of hydroxyapatite (HAP) crystallites embedded in microprisms. The effective anisotropic moduli over a representative unit cell (RUC) under the periodic displacement constraint is concisely introduced according to the micromechanics, and a computational strategy is established to calculate these moduli numerically. Finally, the evaluations in the open literature are employed to demonstrate the validity of the elaborated computational strategy, and more investigations are conducted and yield the conclusions such that the material property of the inter-prism regions as well as the prism shapes plays a crucial role in determining the overall anisotropy of HEs.
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Affiliation(s)
- QIANG DENG
- School of Mechanical Engineering, Southwest Jiaotong University, Chengdu 610031, P. R. China
| | - ZHIFANG ZONG
- School of Mechanical Engineering, Southwest Jiaotong University, Chengdu 610031, P. R. China
| | - ZHENWU NING
- School of Mechanical Engineering, Southwest Jiaotong University, Chengdu 610031, P. R. China
| | - JING ZHENG
- School of Mechanical Engineering, Southwest Jiaotong University, Chengdu 610031, P. R. China
| | - JIANTAO LIU
- School of Mechanical Engineering, Southwest Jiaotong University, Chengdu 610031, P. R. China
- Laboratoire de Mécanique d’Evry, Université d’Evry, 40 rue du Pelvoux, Évry 91020, France
| | - ZHONGRONG ZHOU
- School of Mechanical Engineering, Southwest Jiaotong University, Chengdu 610031, P. R. China
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14
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Ding C, Chen Z, Li J. From molecules to macrostructures: recent development of bioinspired hard tissue repair. Biomater Sci 2017; 5:1435-1449. [DOI: 10.1039/c7bm00247e] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
This review summarizes the bioinspired strategies for hard tissue repair, ranging from molecule-induced mineralization, to microscale assembly to macroscaffold fabrication.
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Affiliation(s)
- Chunmei Ding
- College of Polymer Science and Engineering
- Sichuan University
- Chengdu 610065
- P. R. China
| | - Zhuoxin Chen
- College of Polymer Science and Engineering
- Sichuan University
- Chengdu 610065
- P. R. China
| | - Jianshu Li
- College of Polymer Science and Engineering
- Sichuan University
- Chengdu 610065
- P. R. China
- State Key Laboratory of Polymer Materials Engineering
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15
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Yilmaz ED, Schneider GA. Mechanical behavior of enamel rods under micro-compression. J Mech Behav Biomed Mater 2016; 63:183-194. [PMID: 27415405 DOI: 10.1016/j.jmbbm.2016.06.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 05/09/2016] [Accepted: 06/17/2016] [Indexed: 11/24/2022]
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16
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Zheng J, Zeng Y, Wen J, Zheng L, Zhou Z. Impact wear behavior of human tooth enamel under simulated chewing conditions. J Mech Behav Biomed Mater 2016; 62:119-127. [DOI: 10.1016/j.jmbbm.2016.04.039] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 03/28/2016] [Accepted: 04/28/2016] [Indexed: 11/27/2022]
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17
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La Fontaine A, Zavgorodniy A, Liu H, Zheng R, Swain M, Cairney J. Atomic-scale compositional mapping reveals Mg-rich amorphous calcium phosphate in human dental enamel. SCIENCE ADVANCES 2016; 2:e1601145. [PMID: 27617291 PMCID: PMC5014466 DOI: 10.1126/sciadv.1601145] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 08/09/2016] [Indexed: 05/19/2023]
Abstract
Human dental enamel, the hardest tissue in the body, plays a vital role in protecting teeth from wear as a result of daily grinding and chewing as well as from chemical attack. It is well established that the mechanical strength and fatigue resistance of dental enamel are derived from its hierarchical structure, which consists of periodically arranged bundles of hydroxyapatite (HAP) nanowires. However, we do not yet have a full understanding of the in vivo HAP crystallization process that leads to this structure. Mg(2+) ions, which are present in many biological systems, regulate HAP crystallization by stabilizing its precursor, amorphous calcium phosphate (ACP), but their atomic-scale distribution within HAP is unknown. We use atom probe tomography to provide the first direct observations of an intergranular Mg-rich ACP phase between the HAP nanowires in mature human dental enamel. We also observe Mg-rich elongated precipitates and pockets of organic material among the HAP nanowires. These observations support the postclassical theory of amelogenesis (that is, enamel formation) and suggest that decay occurs via dissolution of the intergranular phase. This information is also useful for the development of more accurate models to describe the mechanical behavior of teeth.
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Affiliation(s)
- Alexandre La Fontaine
- School of Aerospace, Mechanical, and Mechatronic Engineering, University of Sydney, Sydney, New South Wales 2006, Australia
- Australian Centre for Microscopy and Microanalysis, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Alexander Zavgorodniy
- Faculty of Dentistry, University of Sydney, Sydney, New South Wales 2006, Australia
- Institute of Dental Research, Westmead Centre for Oral Health, Sydney, New South Wales 2145, Australia
| | - Howgwei Liu
- Australian Centre for Microscopy and Microanalysis, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Rongkun Zheng
- School of Physics, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Michael Swain
- Faculty of Dentistry, University of Sydney, Sydney, New South Wales 2006, Australia
- Faculty of Dentistry, Kuwait University, P. O. Box 24923, Safat 13110, Kuwait
| | - Julie Cairney
- School of Aerospace, Mechanical, and Mechatronic Engineering, University of Sydney, Sydney, New South Wales 2006, Australia
- Australian Centre for Microscopy and Microanalysis, University of Sydney, Sydney, New South Wales 2006, Australia
- Corresponding author.
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18
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Constantino PJ, Borrero‐Lopez O, Pajares A, Lawn BR. Simulation of enamel wear for reconstruction of diet and feeding behavior in fossil animals: A micromechanics approach. Bioessays 2015; 38:89-99. [DOI: 10.1002/bies.201500094] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | - Oscar Borrero‐Lopez
- Departamento de Ingeniería MecánicaEnergética y de los MaterialesUniversidad de ExtremaduraBadajozSpain
| | - Antonia Pajares
- Departamento de Ingeniería MecánicaEnergética y de los MaterialesUniversidad de ExtremaduraBadajozSpain
| | - Brian R. Lawn
- Materials Measurement LaboratoryNational Institute of Standards and TechnologyGaithersburgMDUSA
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19
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Abstract
Mature tooth enamel is acellular and does not regenerate itself. Developing technologies that rebuild tooth enamel and preserve tooth structure is therefore of great interest. Considering the importance of amelogenin protein in dental enamel formation, its ability to control apatite mineralization in vitro, and its potential to be applied in fabrication of future bio-inspired dental material this review focuses on two major subjects: amelogenin and enamel biomimetics. We review the most recent findings on amelogenin secondary and tertiary structural properties with a focus on its interactions with different targets including other enamel proteins, apatite mineral, and phospholipids. Following a brief overview of enamel hierarchical structure and its mechanical properties we will present the state-of-the-art strategies in the biomimetic reconstruction of human enamel.
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Affiliation(s)
- Qichao Ruan
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA 90033, USA
| | - Janet Moradian-Oldak
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA 90033, USA
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20
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Yilmaz ED, Jelitto H, Schneider GA. Uniaxial compressive behavior of micro-pillars of dental enamel characterized in multiple directions. Acta Biomater 2015; 16:187-95. [PMID: 25620794 DOI: 10.1016/j.actbio.2015.01.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 12/15/2014] [Accepted: 01/12/2015] [Indexed: 12/22/2022]
Abstract
In this work, the compressive elastic modulus and failure strength values of bovine enamel at the first hierarchical level formed by hydroxyapatite (HA) nanofibers and organic matter are identified in longitudinal, transverse and oblique direction with the uniaxial micro-compression method. The elastic modulus values (∼70 GPa) measured here are within the range of results reported in the literature but these values were found surprisingly uniform in all orientations as opposed to the previous nanoindentation findings revealing anisotropic elastic properties in enamel. Failure strengths were recorded up to ∼1.7 GPa and different failure modes (such as shear, microbuckling, fiber fracture) governed by the orientation of the HA nanofibers were visualized. Structural irregularities leading to mineral contacts between the nanofibers are postulated as the main reason for the high compressive strength and direction-independent elastic behavior on enamels first hierarchical level.
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Affiliation(s)
- Ezgi D Yilmaz
- Institute of Advanced Ceramics, Hamburg University of Technology, Hamburg, Germany
| | - Hans Jelitto
- Institute of Advanced Ceramics, Hamburg University of Technology, Hamburg, Germany
| | - Gerold A Schneider
- Institute of Advanced Ceramics, Hamburg University of Technology, Hamburg, Germany.
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21
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Ruan Q, Moradian-Oldak J. Amelogenin and enamel biomimetics. J Mater Chem B 2015. [DOI: 10.1039/c5tb00163c and 21=21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mature tooth enamel is acellular and does not regenerate itself.
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Affiliation(s)
- Qichao Ruan
- Center for Craniofacial Molecular Biology
- Herman Ostrow School of Dentistry
- University of Southern California
- Los Angeles
- USA
| | - Janet Moradian-Oldak
- Center for Craniofacial Molecular Biology
- Herman Ostrow School of Dentistry
- University of Southern California
- Los Angeles
- USA
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22
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Jia Y, Xuan FZ, Yang F. Finite element analysis of depth effect on measuring elastic modulus of a core-shell structure for application of instrumented indentation in tooth enamel. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2014; 37:84-9. [PMID: 24582226 DOI: 10.1016/j.msec.2013.12.042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 12/09/2013] [Accepted: 12/27/2013] [Indexed: 11/30/2022]
Abstract
Tooth enamel is a complex structure, consisting of numerous enamel rods surrounded by a protein-rich sheath. Considering the possible effect of the protein-rich sheath on the indentation deformation of an enamel rod and the limitation of the Oliver-Pharr method in measuring the elastic modulus of the enamel rod, we used a finite element method to analyze the indentation deformation of an elastic-perfectly plastic cylinder surrounded by an elastic-perfectly plastic film. A concept of the threshold indentation depth was proposed, at which the percentage error of the measured modulus of the cylinder is ±10%. For the indentation depth less than the threshold indentation depth, the elastic modulus measured from the indentation test can be approximated as the intrinsic elastic modulus of the cylinder. The normalized threshold indentation depth strongly depends on the modulus ratio of the film to the cylinder and the ratio of the film thickness to the cylinder radius. The results can be used to guide the use of the Oliver-Pharr method in characterizing the mechanical properties of tooth enamel and bio-composites with core-shell structures.
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Affiliation(s)
- Yunfei Jia
- Key Laboratory of Pressure System and Safety, MOE, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China; Materials Program, Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Fu-Zhen Xuan
- Key Laboratory of Pressure System and Safety, MOE, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China.
| | - Fuqian Yang
- Materials Program, Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506, USA.
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23
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Size dependent elastic modulus and mechanical resilience of dental enamel. J Biomech 2014; 47:1060-6. [DOI: 10.1016/j.jbiomech.2013.12.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 12/12/2013] [Accepted: 12/22/2013] [Indexed: 11/22/2022]
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24
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Sui T, Lunt AJG, Baimpas N, Sandholzer MA, Hu J, Dolbnya IP, Landini G, Korsunsky AM. Hierarchical modelling of in situ elastic deformation of human enamel based on photoelastic and diffraction analysis of stresses and strains. Acta Biomater 2014; 10:343-54. [PMID: 24121194 DOI: 10.1016/j.actbio.2013.09.043] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 09/25/2013] [Accepted: 09/30/2013] [Indexed: 11/15/2022]
Abstract
Human enamel is a typical hierarchical mineralized tissue with a two-level composite structure. To date, few studies have focused on how the mechanical behaviour of this tissue is affected by both the rod orientation at the microscale and the preferred orientation of mineral crystallites at the nanoscale. In this study, wide-angle X-ray scattering was used to determine the internal lattice strain response of human enamel samples (with differing rod directions) as a function of in situ uniaxial compressive loading. Quantitative stress distribution evaluation in the birefringent mounting epoxy was performed in parallel using photoelastic techniques. The resulting experimental data was analysed using an advanced multiscale Eshelby inclusion model that takes into account the two-level hierarchical structure of human enamel, and reflects the differing rod directions and orientation distributions of hydroxyapatite crystals. The achieved satisfactory agreement between the model and the experimental data, in terms of the values of multidirectional strain components under the action of differently orientated loads, suggests that the multiscale approach captures reasonably successfully the structure-property relationship between the hierarchical architecture of human enamel and its response to the applied forces. This novel and systematic approach can be used to improve the interpretation of the mechanical properties of enamel, as well as of the textured hierarchical biomaterials in general.
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Affiliation(s)
- Tan Sui
- Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK.
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25
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Abstract
In situ synchrotron X-ray scattering and diffraction, in combination with micromechanical testing, can provide quantitative information on the nanoscale mechanics of biomineralized composites, such as bone, nacre, and enamel. Due to the hierarchical architecture of these systems, the methodology for extraction of mechanical parameters at the molecular and supramolecular scale requires special considerations regarding design of mechanical test apparatus, sample preparation and testing, data analysis, and interpretation of X-ray structural information in terms of small-scale mechanics. In this chapter, this methodology is described using as a case study the deformation mechanisms at the fibrillar and mineral particle level in cortical bone. Following a description of the sample preparation, testing, and analysis procedures for bone in general, two applications of the method-to understand fibrillar-level mechanics in tension and bending in a mouse model of rachitic disease-are presented, together with a discussion of how to relate in situ scattering and diffraction data acquired during mechanical testing to nanostructural models for deformation of biomineralized composites.
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Affiliation(s)
- Angelo Karunaratne
- Queen Mary University of London, School of Engineering and Material Sciences, London, United Kingdom
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26
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Jia YF, Xuan FZ. Anisotropic fatigue behavior of human enamel characterized by multi-cycling nanoindentation. J Mech Behav Biomed Mater 2012; 16:163-8. [DOI: 10.1016/j.jmbbm.2012.10.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 10/10/2012] [Accepted: 10/12/2012] [Indexed: 11/25/2022]
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27
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Campbell SE, Cuozzo FP, Sauther ML, Sponheimer M, Ferguson VL. Nanoindentation of lemur enamel: an ecological investigation of mechanical property variations within and between sympatric species. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2012; 148:178-90. [PMID: 22610894 DOI: 10.1002/ajpa.21582] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The common morphological metrics of size, shape, and enamel thickness of teeth are believed to reflect the functional requirements of a primate's diet. However, the mechanical and material properties of enamel also contribute to tooth function, yet are rarely studied. Substantial wear and tooth loss previously documented in Lemur catta at the Beza Mahafaly Special Reserve suggests that their dental morphology, structure, and possibly their enamel are not adapted for their current fallback food (the mechanically challenging tamarind fruit). In this study, we investigate the nanomechanical properties, mineralization, and microstructure of the enamel of three sympatric lemur species to provide insight into their dietary functional adaptations. Mechanical properties measured by nanoindentation were compared to measurements of mineral content, prism orientation, prism size, and enamel thickness using electron microscopy. Mechanical properties of all species were similar near the enamel dentin junction and variations correlated with changes in microstructure (e.g., prism size) and mineral content. Severe wear and microcracking within L. catta's enamel were associated with up to a 43% reduction in nanomechanical properties in regions of cracking versus intact enamel. The mechanical and material properties of L. catta's enamel are similar to those of sympatric folivores and suggest that they are not uniquely mechanically adapted to consume the physically challenging tamarind fruit. An understanding of the material and mechanical properties of enamel is required to fully elucidate the functional and ecological adaptations of primate teeth.
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Affiliation(s)
- Sara E Campbell
- Department of Mechanical Engineering, University of Colorado, Boulder, CO 80309, USA
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28
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Wang C, Li Y, Wang X, Zhang L, Tiantang, Fu B. The Enamel Microstructures of Bovine Mandibular Incisors. Anat Rec (Hoboken) 2012; 295:1698-706. [DOI: 10.1002/ar.22543] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 06/26/2012] [Indexed: 11/07/2022]
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29
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An B, Wang R, Arola D, Zhang D. The role of property gradients on the mechanical behavior of human enamel. J Mech Behav Biomed Mater 2012; 9:63-72. [PMID: 22498284 DOI: 10.1016/j.jmbbm.2012.01.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 01/04/2012] [Accepted: 01/14/2012] [Indexed: 11/16/2022]
Abstract
In this study, the mechanical design principles of human enamel were evaluated using a hybrid experimental and computational approach. Nanoindentation was applied to evaluate the load-depth response of human enamel, and Vickers indentations were used to assess the damage behavior. An elastic-plastic numerical model was then developed to analyze the stress and strain distribution about the indentations, and to characterize energy dissipation about indents in three locations including inner, middle and outer enamel. Results confirm that enamel exhibits a gradient in its mechanical behavior. Outer enamel has a limited potential for energy dissipation by inelastic deformation, indicating that the ability of outer enamel to resist fracture is low. While inner enamel, the region close Dentin Enamel Junction (DEJ), possesses less resistance to penetration deformation, it has a much higher capacity to dissipate energy by inelastic deformation than outer enamel. The computational simulations identified that the gradients in mechanical properties of human enamel promote resistance to penetration, energy dissipation and mitigation of fracture, all critical performance requirements of human teeth.
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Affiliation(s)
- Bingbing An
- Shanghai Institute of Applied Mathematics and Mechanics, Shanghai, 200072, PR China
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30
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Raue L, Klein H. Calculation of anisotropic properties of dental enamel from synchrotron data. JOURNAL OF SYNCHROTRON RADIATION 2011; 18:550-556. [PMID: 21685670 DOI: 10.1107/s0909049511011071] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Accepted: 04/26/2011] [Indexed: 05/30/2023]
Abstract
Obtaining information about the intrinsic structure of polycrystalline materials is of prime importance owing to the anisotropic behaviour of individual crystallites. Grain orientation and its statistical distribution, i.e. the texture, have an important influence on the material properties. Crystallographic orientations play an important role in all kinds of polycrystalline materials such as metallic, geological and biological. Using synchrotron diffraction techniques the texture can be measured with high local and angular resolving power. Here methods are presented which allow the spatial orientation of the crystallites to be determined and information about the anisotropy of mechanical properties, such as elastic modulus or thermal expansion, to obtained. The methods are adapted to all crystal and several sample symmetries as well as to different phases, for example with overlapping diffraction peaks. To demonstrate the abilities of the methods, human dental enamel has been chosen, showing even overlapping diffraction peaks. Likewise it is of special interest to learn more about the orientation and anisotropic properties of dental enamel, since only basic information is available up to now. The texture of enamel has been found to be a tilted fibre texture of high strength (up to 12.5×). The calculated elastic modulus is up to 155 GPa and the thermal expansion up to 22.3 × 10(-6)°C(-1).
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Affiliation(s)
- Lars Raue
- GZG, Department of Crystallography, Georg-August-University of Göttingen, Göttingen, Germany.
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31
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Lee JJW, Constantino PJ, Lucas PW, Lawn BR. Fracture in teeth: a diagnostic for inferring bite force and tooth function. Biol Rev Camb Philos Soc 2011; 86:959-74. [PMID: 21507194 DOI: 10.1111/j.1469-185x.2011.00181.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Teeth are brittle and highly susceptible to cracking. We propose that observations of such cracking can be used as a diagnostic tool for predicting bite force and inferring tooth function in living and fossil mammals. Laboratory tests on model tooth structures and extracted human teeth in simulated biting identify the principal fracture modes in enamel. Examination of museum specimens reveals the presence of similar fractures in a wide range of vertebrates, suggesting that cracks extended during ingestion or mastication. The use of 'fracture mechanics' from materials engineering provides elegant relations for quantifying critical bite forces in terms of characteristic tooth size and enamel thickness. The role of enamel microstructure in determining how cracks initiate and propagate within the enamel (and beyond) is discussed. The picture emerges of teeth as damage-tolerant structures, full of internal weaknesses and defects and yet able to contain the expansion of seemingly precarious cracks and fissures within the enamel shell. How the findings impact on dietary pressures forms an undercurrent of the study.
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Affiliation(s)
- James J-W Lee
- Ceramics Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
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32
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Snead ML, Zhu DH, Lei Y, Luo W, Bringas PO, Sucov HM, Rauth RJ, Paine ML, White SN. A simplified genetic design for mammalian enamel. Biomaterials 2011; 32:3151-7. [PMID: 21295848 DOI: 10.1016/j.biomaterials.2011.01.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Accepted: 01/08/2011] [Indexed: 01/30/2023]
Abstract
A biomimetic replacement for tooth enamel is urgently needed because dental caries is the most prevalent infectious disease to affect man. Here, design specifications for an enamel replacement material inspired by Nature are deployed for testing in an animal model. Using genetic engineering we created a simplified enamel protein matrix precursor where only one, rather than dozens of amelogenin isoforms, contributed to enamel formation. Enamel function and architecture were unaltered, but the balance between the competing materials properties of hardness and toughness was modulated. While the other amelogenin isoforms make a modest contribution to optimal biomechanical design, the enamel made with only one amelogenin isoform served as a functional substitute. Where enamel has been lost to caries or trauma a suitable biomimetic replacement material could be fabricated using only one amelogenin isoform, thereby simplifying the protein matrix parameters by one order of magnitude.
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Affiliation(s)
- Malcolm L Snead
- Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, CA 90033, USA.
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33
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Influences of spherical tip radius, contact depth, and contact area on nanoindentation properties of bone. J Biomech 2011; 44:285-90. [DOI: 10.1016/j.jbiomech.2010.10.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Accepted: 10/12/2010] [Indexed: 11/19/2022]
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34
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Stavrianos C, Papadopoul C, Vasiliadis L, Dagkalis P, Stavrianou I, Petalotis N. Enamel Structure and Forensic Use. ACTA ACUST UNITED AC 2010. [DOI: 10.3923/rjbsci.2010.650.655] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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35
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Mangum J, Crombie F, Kilpatrick N, Manton D, Hubbard M. Surface Integrity Governs the Proteome of Hypomineralized Enamel. J Dent Res 2010; 89:1160-5. [DOI: 10.1177/0022034510375824] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Growing interest in the treatment and prevention of Molar/Incisor Hypomineralization (MIH) warrants investigation into the protein composition of hypomineralized enamel. Hypothesizing abnormality akin to amelogenesis imperfecta, we profiled proteins in hypomineralized enamel from human permanent first molars using a biochemical approach. Hypomineralized enamel was found to have from 3- to 15-fold higher protein content than normal, but a near-normal level of residual amelogenins. This distinguished MIH from hypomaturation defects with high residual amelogenins (amelogenesis imperfecta, fluorosis) and so typified it as a hypocalcification defect. Second, hypomineralized enamel was found to have accumulated various proteins from oral fluid and blood, with differential incorporation depending on integrity of the enamel surface. Pathogenically, these results point to a pre-eruptive disturbance of mineralization involving albumin and, in cases with post-eruptive breakdown, subsequent protein adsorption on the exposed hydroxyapatite matrix. These insights into the pathogenesis and properties of hypomineralized enamel hold significance for prevention and treatment of MIH.
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Affiliation(s)
- J.E. Mangum
- Department of Pharmacology, The University of Melbourne, Medical Building, Corner of Grattan Street and Royal Parade, Parkville 3010, Victoria, Australia
| | - F.A. Crombie
- Melbourne Dental School, The University of Melbourne
| | - N. Kilpatrick
- Department of Dentistry, The Royal Children’s Hospital, Melbourne
| | - D.J. Manton
- Melbourne Dental School, The University of Melbourne
| | - M.J. Hubbard
- Department of Pharmacology, The University of Melbourne, Medical Building, Corner of Grattan Street and Royal Parade, Parkville 3010, Victoria, Australia
- Department of Paediatrics, The University of Melbourne
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36
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Systemic disorders and their influence on the development of dental hard tissues: a literature review. J Dent 2010; 38:296-306. [PMID: 20004698 DOI: 10.1016/j.jdent.2009.12.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 11/21/2009] [Accepted: 12/03/2009] [Indexed: 01/20/2023] Open
Abstract
OBJECTIVES This report highlights the influence of a number of disorders with systemic physiological effects that impact on the development of dental hard tissues. It focuses in particular, on the pathological effects of systemic conditions with less well recognised, but no less important, impacts on dental development. Such conditions, include cystic fibrosis, HIV/AIDS, leukaemia, Alstrom syndrome, hypophosphatasia, Prader-Willi syndrome, Tricho-dento-osseous syndrome, tuberous sclerosis, familial steroid dehydrogenase deficiency and epidermolysis bullosa. These, along with developmental and environmental causes of enamel and dentine defects, are discussed and the possible aetiology of such effects are proposed. Furthermore, the dental management and long-term dental care of these patients is outlined. SOURCES MEDLINE/PubMed. CONCLUSIONS Enamel and dentine defects can present with a wide spectrum of clinical features and may be caused by a variety of factors occurring throughout tooth development from before birth to adulthood. These may include host traits, genetic factors, immunological responses to cariogenic bacteria, saliva composition, environmental and behavioural factors and systemic diseases. These diseases and their spectrum of clinical manifestations on the organs affected (including the dentition) require an increased knowledge by dental practitioners of the disease processes, aetiology, relevant treatment strategies and prognosis, and must encompass more than simply the management of the dental requirements of the patient. It is important that the impact of the disease and its treatment, particularly in respect of immunosuppression where dental interventions may become life-threatening, is also taken into consideration.
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37
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Ang SF, Bortel EL, Swain MV, Klocke A, Schneider GA. Size-dependent elastic/inelastic behavior of enamel over millimeter and nanometer length scales. Biomaterials 2009; 31:1955-63. [PMID: 19969342 DOI: 10.1016/j.biomaterials.2009.11.045] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Accepted: 11/17/2009] [Indexed: 10/20/2022]
Abstract
The microstructure of enamel like most biological tissues has a hierarchical structure which determines their mechanical behavior. However, current studies of the mechanical behavior of enamel lack a systematic investigation of these hierarchical length scales. In this study, we performed macroscopic uni-axial compression tests and the spherical indentation with different indenter radii to probe enamel's elastic/inelastic transition over four hierarchical length scales, namely: 'bulk enamel' (mm), 'multiple-rod' (10's microm), 'intra-rod' (100's nm with multiple crystallites) and finally 'single-crystallite' (10's nm with an area of approximately one hydroxyapatite crystallite). The enamel's elastic/inelastic transitions were observed at 0.4-17 GPa depending on the length scale and were compared with the values of synthetic hydroxyapatite crystallites. The elastic limit of a material is important as it provides insights into the deformability of the material before fracture. At the smallest investigated length scale (contact radius approximately 20 nm), elastic limit is followed by plastic deformation. At the largest investigated length scale (contact size approximately 2 mm), only elastic then micro-crack induced response was observed. A map of elastic/inelastic regions of enamel from millimeter to nanometer length scale is presented. Possible underlying mechanisms are also discussed.
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Affiliation(s)
- Siang Fung Ang
- Institute of Advanced Ceramics, Hamburg University of Technology, Hamburg 21073, Germany
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