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Besnard C, Marie A, Sasidharan S, Harper RA, Shelton RM, Landini G, Korsunsky AM. Synchrotron X-ray Studies of the Structural and Functional Hierarchies in Mineralised Human Dental Enamel: A State-of-the-Art Review. Dent J (Basel) 2023; 11:98. [PMID: 37185477 PMCID: PMC10137518 DOI: 10.3390/dj11040098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 03/19/2023] [Accepted: 03/28/2023] [Indexed: 05/17/2023] Open
Abstract
Hard dental tissues possess a complex hierarchical structure that is particularly evident in enamel, the most mineralised substance in the human body. Its complex and interlinked organisation at the Ångstrom (crystal lattice), nano-, micro-, and macro-scales is the result of evolutionary optimisation for mechanical and functional performance: hardness and stiffness, fracture toughness, thermal, and chemical resistance. Understanding the physical-chemical-structural relationships at each scale requires the application of appropriately sensitive and resolving probes. Synchrotron X-ray techniques offer the possibility to progress significantly beyond the capabilities of conventional laboratory instruments, i.e., X-ray diffractometers, and electron and atomic force microscopes. The last few decades have witnessed the accumulation of results obtained from X-ray scattering (diffraction), spectroscopy (including polarisation analysis), and imaging (including ptychography and tomography). The current article presents a multi-disciplinary review of nearly 40 years of discoveries and advancements, primarily pertaining to the study of enamel and its demineralisation (caries), but also linked to the investigations of other mineralised tissues such as dentine, bone, etc. The modelling approaches informed by these observations are also overviewed. The strategic aim of the present review was to identify and evaluate prospective avenues for analysing dental tissues and developing treatments and prophylaxis for improved dental health.
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Affiliation(s)
- Cyril Besnard
- MBLEM, Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, Oxfordshire, UK
| | - Ali Marie
- MBLEM, Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, Oxfordshire, UK
| | - Sisini Sasidharan
- MBLEM, Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, Oxfordshire, UK
| | - Robert A. Harper
- School of Dentistry, University of Birmingham, 5 Mill Pool Way, Edgbaston, Birmingham B5 7EG, West Midlands, UK
| | - Richard M. Shelton
- School of Dentistry, University of Birmingham, 5 Mill Pool Way, Edgbaston, Birmingham B5 7EG, West Midlands, UK
| | - Gabriel Landini
- School of Dentistry, University of Birmingham, 5 Mill Pool Way, Edgbaston, Birmingham B5 7EG, West Midlands, UK
| | - Alexander M. Korsunsky
- MBLEM, Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, Oxfordshire, UK
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Nascimento AS, Rodrigues JFB, Torres RHN, Santos KO, Fook MVL, Albuquerque MSD, Lima EAD, Filgueira PTD, Santos JBMD, Oliveira LJRD, Braz R. Physicomechanical and thermal analysis of bulk-fill and conventional composites. Braz Oral Res 2019; 33:e008. [PMID: 30892408 DOI: 10.1590/1807-3107bor-2019.vol33.0008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 01/09/2019] [Indexed: 11/22/2022] Open
Abstract
The aim of this study was to evaluate the degree of conversion (DC) and the thermal stability of bulk-fill and conventional composite resins. Eleven composite resin samples were prepared to evaluate the DC, Vickers microhardness (VMH), mass and residue/particle loss, glass transition temperature (Tg), enthalpy, and linear coefficient of thermal expansion (CTE) using infrared spectroscopy (FTIR), microdurometer analyses, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dilatometry (DIL). The data were subjected to statistical analysis, with a significance level of 95%. DC and VMH were not influenced by the polymerized side of the sample, and statistical differences were recorded only among the materials. Decomposition temperature, melting, and mass and residue loss were dependent on the material and on the evaluation condition (polymerized and non-polymerized). Tg values were similar between the composites, without statistically significant difference, and CTE ranged from 10.5 to 37.1 (10-6/°C), with no statistical difference between the materials. There was a moderate negative correlation between CTE and the % of load particles, by weight. Most resins had a DC above that which is reported in the literature. TGA, Tg, and CTE analyses showed the thermal behavior of the evaluated composites, providing data for future research, assisting with the choice of material for direct or semidirect restorations, and helping choose the appropriate temperature for increasing the DC of such materials.
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Affiliation(s)
| | - José Filipe Bacalhau Rodrigues
- Universidade Federal de Campina Grande - UFCG , Department of Materials Science and Engineering, Campina Grande, PB, Brazil
| | | | - Kleilton Oliveira Santos
- Universidade Federal de Campina Grande - UFCG , Department of Materials Science and Engineering, Campina Grande, PB, Brazil
| | - Marcus Vinicius Lia Fook
- Universidade Federal de Campina Grande - UFCG , Department of Materials Science and Engineering, Campina Grande, PB, Brazil
| | | | - Eliane Alves de Lima
- Universidade de Pernamburco - UPE, Department of Dentistry, Tabatinga Camarajibe, PE, Brazil
| | | | - João Batista Morais Dos Santos
- Universidade Federal de Campina Grande - UFCG , Department of Materials Science and Engineering, Campina Grande, PB, Brazil
| | | | - Rodivan Braz
- Universidade de Pernamburco - UPE, Department of Dentistry, Tabatinga Camarajibe, PE, Brazil
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Al-Mosawi M, Davis GR, Bushby A, Montgomery J, Beaumont J, Al-Jawad M. Crystallographic texture and mineral concentration quantification of developing and mature human incisal enamel. Sci Rep 2018; 8:14449. [PMID: 30262903 PMCID: PMC6160435 DOI: 10.1038/s41598-018-32425-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 08/30/2018] [Indexed: 11/08/2022] Open
Abstract
For human dental enamel, what is the precise mineralization progression spatially and the precise timing of mineralization? This is an important question in the fundamental understanding of matrix-mediated biomineralization events, but in particular because we can use our understanding of this natural tissue growth in humans to develop biomimetic approaches to repair and replace lost enamel tissue. It is important to understand human tissues in particular since different species have quite distinct spatial and temporal progression of mineralization. In this study, five human central incisors at different stages of enamel maturation/mineralization were spatially mapped using synchrotron X-ray diffraction and X-ray microtomography techniques. From the earliest developmental stage, two crystallite-orientation populations coexist with angular separations between the crystallite populations of approximately 40° varying as a function of position within the tooth crown. In general, one population had significantly lower texture magnitude and contributed a higher percentage to the overall crystalline structure, compared to the other population which contributed only 20-30% but had significantly higher texture magnitude. This quantitative analysis allows us to understand the complex and co-operative structure-function relationship between two populations of crystallites within human enamel. There was an increase in the mineral concentration from the enamel-dentin junction peripherally and from the incisal tip cervically as a function of maturation time. Quantitative backscattered-electron analyses showed that mineralization of prism cores precedes that of prism boundaries. These results provide new insights into the precise understanding of the natural growth of human enamel.
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Affiliation(s)
- Mohammed Al-Mosawi
- Institute of Dentistry, Barts and the London School of Medicine and Dentistry, Queen Mary, University of London, London, E1 4NS, United Kingdom
| | - Graham Roy Davis
- Institute of Dentistry, Barts and the London School of Medicine and Dentistry, Queen Mary, University of London, London, E1 4NS, United Kingdom
| | - Andy Bushby
- School of Engineering and Materials Science, Queen Mary University of London, London, E1 4NS, United Kingdom
| | - Janet Montgomery
- Department of Archaeology, Durham University, South Road, Durham, DH1 3LE, United Kingdom
| | - Julia Beaumont
- School of Archaeological and Forensic Sciences, University of Bradford, Bradford, BD7 1DP, United Kingdom
| | - Maisoon Al-Jawad
- Institute of Dentistry, Barts and the London School of Medicine and Dentistry, Queen Mary, University of London, London, E1 4NS, United Kingdom.
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Bilandžić MD, Wollgarten S, Stollenwerk J, Poprawe R, Esteves-Oliveira M, Fischer H. Glass-ceramic coating material for the CO 2 laser based sintering of thin films as caries and erosion protection. Dent Mater 2017; 33:995-1003. [DOI: 10.1016/j.dental.2017.06.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 06/08/2017] [Accepted: 06/09/2017] [Indexed: 12/16/2022]
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Raue L, Hartmann CD, Rödiger M, Bürgers R, Gersdorff N. Anisotropic local physical properties of human dental enamel in comparison to properties of some common dental filling materials. Acta Odontol Scand 2014; 72:591-6. [PMID: 24460030 DOI: 10.3109/00016357.2013.878391] [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] [Indexed: 11/13/2022]
Abstract
OBJECTIVE A major aspect in evaluating the quality of dental materials is their physical properties. Their properties should be a best fit of the ones of dental hard tissues. Manufacturers give data sheets for each material. The properties listed are characterized by a specific value. This assumes (but does not prove) that there is no direction dependence of the properties. However, dental enamel has direction-dependent properties which additionally vary with location in the tooth. The aim of this paper is to show the local direction dependence of physical properties like the elastic modulus or the thermal expansion in dental hard tissues. With this knowledge the 'perfect filling/dental material' could be characterized. MATERIALS AND METHOD Enamel sections of ∼400-500 μm thickness have been cut with a diamond saw from labial/buccal to palatal/lingual (canine, premolar and molar) and parallel to labial (incisor). Crystallite arrangements have been measured in over 400 data points on all types of teeth with x-ray scattering techniques, known from materials science. RESULTS X-ray scattering measurements show impressively that dental enamel has a strong direction dependence of its physical properties which also varies with location within the tooth. Dental materials possess only little or no property direction dependence. Therefore, a mismatch was found between enamel and dental materials properties. CONCLUSION Since dental materials should possess equal (direction depending) properties, worthwhile properties could be characterized by transferring the directional properties of enamel into a property 'wish list' which future dental materials should fulfil. Hereby the 'perfect dental material' can be characterized.
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Affiliation(s)
- Lars Raue
- Department of Prosthodontics, Center for Dentistry, Oral Medicine and Craniomaxillofacial Surgery, University Clinical Center, Georg-August-University , Goettingen , Germany
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Raue L. input4MAUD: an efficient program for automatic two-dimensional diffraction image series input and/or batch refinement withMAUD. J Appl Crystallogr 2014. [DOI: 10.1107/s1600576714020470] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
In materials science or applied crystallography, X-ray diffraction represents a versatile and useful method with which one can obtain the orientation of single crystals or even the texture of a polycrystalline material. When the investigated sample consists of many phases, or phases of low symmetry, it becomes difficult to measure pole figures from single diffraction peaks. A combined Rietveld–texture analysis with the programMAUDis perfectly suitable to deal with conditions of overlapping diffraction peaks, including those arising from different phases. Even though nearly no alternative toMAUDexists, it is not always easy to use. The input of a file series of two-dimensional diffraction images, for example from a texture measurement, can be time consuming since each individual image must be loaded manually, and only the newest beta version ofMAUDallows semi-automated file input. The new programinput4MAUD, which is presented in this paper, offers a much more efficient way to automate both single and batch file series input intoMAUDas well as the preparation of basic batch refinements withMAUD. input4MAUDis written in Visual C++ and is currently available as a 32-bit statically compiled binary executable file for Windows.
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Dominguez JA, Bittencourt B, Michel M, Sabino N, Gomes JC, Gomes OMM. Ultrastructural evaluation of enamel after dental bleaching associated with fluoride. Microsc Res Tech 2012; 75:1093-8. [DOI: 10.1002/jemt.22035] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2011] [Accepted: 02/07/2012] [Indexed: 11/11/2022]
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New insights in prism orientation within human enamel. Arch Oral Biol 2012; 57:271-6. [DOI: 10.1016/j.archoralbio.2011.08.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 08/10/2011] [Accepted: 08/21/2011] [Indexed: 11/24/2022]
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