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Yu HP, Zhu YJ. Guidelines derived from biomineralized tissues for design and construction of high-performance biomimetic materials: from weak to strong. Chem Soc Rev 2024; 53:4490-4606. [PMID: 38502087 DOI: 10.1039/d2cs00513a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
Living organisms in nature have undergone continuous evolution over billions of years, resulting in the formation of high-performance fracture-resistant biomineralized tissues such as bones and teeth to fulfill mechanical and biological functions, despite the fact that most inorganic biominerals that constitute biomineralized tissues are weak and brittle. During the long-period evolution process, nature has evolved a number of highly effective and smart strategies to design chemical compositions and structures of biomineralized tissues to enable superior properties and to adapt to surrounding environments. Most biomineralized tissues have hierarchically ordered structures consisting of very small building blocks on the nanometer scale (nanoparticles, nanofibers or nanoflakes) to reduce the inherent weaknesses and brittleness of corresponding inorganic biominerals, to prevent crack initiation and propagation, and to allow high defect tolerance. The bioinspired principles derived from biomineralized tissues are indispensable for designing and constructing high-performance biomimetic materials. In recent years, a large number of high-performance biomimetic materials have been prepared based on these bioinspired principles with a large volume of literature covering this topic. Therefore, a timely and comprehensive review on this hot topic is highly important and contributes to the future development of this rapidly evolving research field. This review article aims to be comprehensive, authoritative, and critical with wide general interest to the science community, summarizing recent advances in revealing the formation processes, composition, and structures of biomineralized tissues, providing in-depth insights into guidelines derived from biomineralized tissues for the design and construction of high-performance biomimetic materials, and discussing recent progress, current research trends, key problems, future main research directions and challenges, and future perspectives in this exciting and rapidly evolving research field.
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Affiliation(s)
- Han-Ping Yu
- State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, P. R. China.
| | - Ying-Jie Zhu
- State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, P. R. China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
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Konsek JP, Knaus J, Avaro J, Sturm EV, Cölfen H. Cross-Linking of Apatite-Gelatin Nanocomposites as the Basis for Dentine Replacement Materials. ACS Biomater Sci Eng 2021; 9:1815-1822. [PMID: 34962771 DOI: 10.1021/acsbiomaterials.1c01071] [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: 11/29/2022]
Abstract
A novel approach for the production of a bioinspired dentine replacement material is introduced. An apatite-gelatin nanocomposite material was cross-linked with various cross-linkers. These nanocomposites have a high resemblance to mammalian dentine regarding its composition and properties. A precipitation reaction was used to produce apatite-gelatin nanocomposites as starting materials. Cross-linking of the gelatin has to be performed to produce dentine-like and thus tough and robust apatite-gelatin nanocomposites. Therefore, the efficacy of various protein cross-linkers was tested, and the resulting materials were characterized by scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, and EXAFS as well as CHNS analysis and tested for their mechanical performance using Vickers hardness measurements as well as for their dissolution stability in EDTA. Especially glutaraldehyde, proanthocyanidins, and transglutaminase gave promising results with hardness values of up to 63 HV0.2. To further improve the material properties, we combined the effective cross-linker transglutaminase with casein, which led to an improved interconnection between the single nanocomposite platelets. By doing so, a cross-linked composite was obtained, which shows even higher hardness values than does human dentine, at 76 HV0.2. The combination of apatite-gelatin nanocomposites with an effective cross-linker resulted in a bioinspired material with composition and properties close to those of human dentine.
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Affiliation(s)
- Julian P Konsek
- Physical Chemistry, University of Konstanz, Universitätsstraße 10, Box 714, Konstanz 78457, Germany
| | - Jennifer Knaus
- Physical Chemistry, University of Konstanz, Universitätsstraße 10, Box 714, Konstanz 78457, Germany.,stimOS GmbH, Fritz-Reichle-Ring 2, Radolfzell 78315, Germany
| | - Jonathan Avaro
- Physical Chemistry, University of Konstanz, Universitätsstraße 10, Box 714, Konstanz 78457, Germany.,EMPA-Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, St. Gallen 9014, Switzerland
| | - Elena V Sturm
- Physical Chemistry, University of Konstanz, Universitätsstraße 10, Box 714, Konstanz 78457, Germany
| | - Helmut Cölfen
- Physical Chemistry, University of Konstanz, Universitätsstraße 10, Box 714, Konstanz 78457, Germany
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Thangadurai S, Brumfeld V, Milgram J, Li L, Shahar R. Osteodentin in the Atlantic wolffish (Anarhichas lupus): Dentin or bone? J Morphol 2021; 283:219-235. [PMID: 34910318 DOI: 10.1002/jmor.21438] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 12/04/2021] [Accepted: 12/11/2021] [Indexed: 11/09/2022]
Abstract
The teeth of actinopterygian fish, like those of mammals, consist of a thin outer hyper-mineralized layer (enamel or enameloid) that surrounds a core of dentin. While all mammalian species have a single type of dentin (called orthodentin), various dentin types have been reported in the teeth of actinopterygian fish. The most common type of actinopterygian fish dentin is orthodentin. However, the second most common type of actinopterygian fish dentin, called osteodentin, found in several teleost species and in many Selachians, is structurally radically different from orthodentin. Osteodentin, comprising denteons and inter-denteonal matrix, is characterized by an appearance that is similar to mammalian osteonal bone, however, it lacks cells and a lacuno-canalicular system. The current consensus is that although osteodentin is morphologically different from orthodentin, it is a true dentinal material, the product of odontoblast cells. We present the results of a study of osteodentin found in the teeth of the Atlantic wolffish, Anarhichas lupus. Using a variety of microscopy techniques, high-resolution microCT scans, and micro-indentation we describe the three-dimensional structure of both its components (denteons and inter-denteonal matrix), as well as their mineral density distribution and mechanical properties, at several length-scales. We show that wolffish osteodentin is remarkably similar to the anosteocytic bone of the swords of several swordfish species. We also describe the three-dimensional network of canals found in mature osteodentin. The high density of these canals in a metabolically inactive, acellular tissue casts doubt upon the accepted paradigm, that the canals house a vascular network.
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Affiliation(s)
- Senthil Thangadurai
- Koret School of Veterinary Medicine, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Vlad Brumfeld
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, Israel
| | - Joshua Milgram
- Koret School of Veterinary Medicine, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Ling Li
- Department of Mechanical Engineering, Virginia Polytechnic Institute and State University, Virginia, USA
| | - Ron Shahar
- Koret School of Veterinary Medicine, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
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Gulabivala K, Azam I, Mahdavi-Izadi S, Palmer G, Georgiou G, Knowles JC, Y-L N. Effect of root canal irrigant (sodium hypochlorite & saline) delivery at different temperatures and durations on pre-load and cyclic-loading surface-strain of anatomically different premolars. J Mech Behav Biomed Mater 2021; 121:104640. [PMID: 34126506 DOI: 10.1016/j.jmbbm.2021.104640] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 06/02/2021] [Accepted: 06/05/2021] [Indexed: 11/25/2022]
Abstract
AIM To evaluate the effect of NaOCl (5%) and saline (control) irrigant delivery at different temperatures and durations on pre-load and cyclic-loading tooth-surface-strain (TSS) on anatomically different premolars. METHODOLOGY Single-rooted premolars (n = 36), root-canal-prepared in standard manner, were randomly allocated to six irrigation groups: (A1) NaOCl-21 °C; (A2) NaOCl-60 °C; (A3) saline-21 °C then NaOCl-21 °C; (A4) saline-60 °C then NaOCl-21 °C; (A5) saline-21 °C then NaOCl-60 °C; (A6) saline-60 °C then NaOCl-60 °C. A1-2 received nine 10-min irrigation periods (IP) with NaOCl; A3-6 received nine 10-min IP with saline, followed by 9 IP with NaOCl at different temperature combinations. Premolars (n = 56) with single, fused or double roots prepared by standard protocol, were stratified and randomly allocated to: (B1) saline-21 °C; (B2) saline-80 °C; (B3) NaOCl-21 °C; (B4) NaOCl-80 °C. TSS (μє) was recorded pre-irrigation, post-irrigation and pre-load for each IP and during cyclic loading 2 min after each IP, over 30-274 min, using strain-gauges. Generalised linear mixed models were used for analysis. RESULTS Baseline TSS in double-rooted premolars was significantly (p=0.001) lower than in single/fused-rooted-premolars; and affected by mesial-wall-thickness (p=0.005). There was significant increase in loading-TSS (μє) after NaOCl-21 °C irrigation (p=0.01) but decrease after NaOCl-60 °C irrigation (p=0.001). TSS also increased significantly (p = 0.005) after Saline-80 °C irrigation. Pre-load "strain-shift" was noted only upon first saline delivery but every-time with NaOCl. Strain-shift negatively influenced loading-TSS after saline or NaOCl irrigation (A3-6) but was only significant for saline-21 °C. CONCLUSIONS Tooth anatomy significantly affected its strain characteristics, exhibiting limits within which strain changes occurred. Intra-canal introduction of saline or NaOCl caused non-random strain shifts without loading. Irrigation with NaOCl-21 °C increased loading tooth strain, as did saline-80 °C or NaOCl-80 °C but NaOCl-60 °C decreased it. A "chain-link" model was proposed to explain the findings and tooth biomechanics.
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Affiliation(s)
- K Gulabivala
- Unit of Endodontology, Division of Restorative Dental Science, UK.
| | - I Azam
- Unit of Endodontology, Division of Restorative Dental Science, UK
| | - S Mahdavi-Izadi
- Unit of Endodontology, Division of Restorative Dental Science, UK
| | - G Palmer
- Division of Biomaterials & Tissue Engineering; UCL Eastman Dental Institute, UK
| | - G Georgiou
- Division of Biomaterials & Tissue Engineering; UCL Eastman Dental Institute, UK
| | - J C Knowles
- Division of Biomaterials & Tissue Engineering; UCL Eastman Dental Institute, UK; The Discoveries Centre for Regenerative and Precision Medicine, UCL Campus, London, UK; Department of Nanobiomedical Science and BK21 Plus NBM, Global Research Center for Regenerative Medicine, Dankook University, 518-10, Anseo-dong, Dongnam-gu, Cheonan, Chungcheongnam-do, Republic of Korea
| | - Ng Y-L
- Unit of Endodontology, Division of Restorative Dental Science, UK
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Cementum thickening leads to lower whole tooth mobility and reduced root stresses: An in silico study on aging effects during mastication. J Struct Biol 2021; 213:107726. [PMID: 33781897 DOI: 10.1016/j.jsb.2021.107726] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 03/15/2021] [Accepted: 03/17/2021] [Indexed: 11/21/2022]
Abstract
In the course of a lifetime the crowns of teeth wear off, cementum thickens and the pulp closes-in or may stiffen. Little is known about how these changes affect the tooth response to load. Using a series of finite element models of teeth attached to the jawbone, and by comparing these to a validated model of a 'young' pig 3-rooted tooth, the effects of these structural changes were studied. Models of altered teeth show a stiffer response to mastication even when material properties used are identical to those found in 'young' teeth. This stiffening response to occlusal loads is mostly caused by the thicker cementum found in 'old' teeth. Tensile stresses associated with bending of dentine in the roots fall into a narrower distribution range with lower peak values. It is speculated that this is a possible protective adaptation mechanism of the aging tooth to avoid fracture. The greatest reduction in lateral motion was seen in the bucco-lingual direction. We propose that greater tooth motion during mastication is typical for the young growing animal. This motion is reduced in adulthood, favoring less off-axis loading, possibly to counteract natural bone resorption and consequent compromised anchoring.
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Substantial regional differences in the biomechanical behavior of molar treated with selective caries tissue removal technique: a finite element study. Dent Mater 2021; 37:e162-e175. [PMID: 33358015 DOI: 10.1016/j.dental.2020.11.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 08/07/2020] [Accepted: 11/13/2020] [Indexed: 12/27/2022]
Abstract
OBJECTIVES Selective caries removal (SCR) is recommended over non-selective removal for managing deep carious lesions to avoid pulp exposure and maintain pulp vitality. During SCR, residual carious dentin is left behind and sealed beneath the restoration. The biomechanical effects of such residual lesions on the restored tooth remain unclear and were assessed using finite element modeling (FEM). METHODS Based on μ-CT images of a healthy permanent human third molar, we developed five finite element models. Generic class I and II cavity restorations were modeled where residual lesions of variable sizes were either left or fully removed on occlusal and proximal surfaces. The cavities were restored with adhesive composite. All 3D-FE models were compared with a model of a healthy, non-treated molar. A vertical load of 100 N was applied onto the occlusal surface. RESULTS Regardless of the lesion size, in molars with occlusal lesions higher mean stresses were predicted along the filling-lesion interface than in all other models. The smallest occlusal lesion (Ø1 = 1 mm) resulted in the highest maximum stresses at the filling-lesion interface with large stress concentrations at the filling walls indicating failure risk. In conclusion, lesion site and extent are influencing parameters affecting the filling-lesion interactions and thus the biomechanical behavior of the tooth after SCR. SIGNIFICANCE Retaining carious lesions around the pulpal floor affects the deformation and stress states in tooth-filling complexes. The higher stresses observed in molars with occlusal lesions may affect restoration stability and longevity. Suprisingly, more extended occlusal lesions may provide a more favorable tooth performance than less extended ones. In contrast, in molars with proximal lesions the residual lesion had only limited effect on the tooth's biomechanical condition.
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Prates Soares A, Blunck U, Bitter K, Paris S, Rack A, Zaslansky P. Hard X-ray phase-contrast-enhanced micro-CT for quantifying interfaces within brittle dense root-filling-restored human teeth. JOURNAL OF SYNCHROTRON RADIATION 2020; 27:1015-1022. [PMID: 33566011 PMCID: PMC7336175 DOI: 10.1107/s1600577520005603] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 04/21/2020] [Indexed: 05/28/2023]
Abstract
Bonding of resin composite fillings, for example following root-canal treatment, is a challenge because remaining gaps grow and lead to failure. Here, phase-contrast-enhanced micro-computed tomography (PCE-CT) is used to explore methods of non-destructive quantification of the problem, so that countermeasures can be devised. Five human central incisors with damaged crowns were root-filled followed by restoration with a dental post. Thereafter, the crowns were rebuilt with a resin composite that was bonded conventionally to the tooth with a dental adhesive system (Futurabond U). Each sample was imaged by PCE-CT in a synchrotron facility (ID19, European Synchrotron Radiation Facility) with a pixel size of 650 nm. The reconstructed datasets from each sample were segmented and analysed in a semi-automated manner using ImageJ. PCE-CT at sub-micrometre resolution provided images with an impressive increased contrast and detail when compared with laboratory micro-computed tomography. The interface between the dental adhesive and the tooth was often strongly disrupted by the presence of large debonded gaps (on average 34% ± 15% on all surfaces). The thickness of the gaps spanned 2 µm to 16 µm. There was a large variability in the distribution of gaps within the bonding area in each sample, with some regions around the canal exhibiting up to 100% discontinuity. Although only several micrometres thick, the extensive wide gaps may serve as gateways to biofilm leakage, leading to failure of the restorations. They can also act as stress-raising `cracks' that are likely to expand over time in response to cyclic mechanical loading as a consequence of mastication. The observations here show how PCE-CT can be used as a non-destructive quantitative tool for understanding and improving the performance of clinically used bonded dental restorations.
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Affiliation(s)
- Ana Prates Soares
- Department of Operative and Preventive Dentistry, Charité Universitätsmedizin Berlin, Aßmannshauser Straße 4-6, 14197 Berlin, Germany
| | - Uwe Blunck
- Department of Operative and Preventive Dentistry, Charité Universitätsmedizin Berlin, Aßmannshauser Straße 4-6, 14197 Berlin, Germany
| | - Kerstin Bitter
- Department of Operative and Preventive Dentistry, Charité Universitätsmedizin Berlin, Aßmannshauser Straße 4-6, 14197 Berlin, Germany
| | - Sebastian Paris
- Department of Operative and Preventive Dentistry, Charité Universitätsmedizin Berlin, Aßmannshauser Straße 4-6, 14197 Berlin, Germany
| | - Alexander Rack
- ESRF – The European Synchrotron, CS 40220, Grenoble Cedex 9, Grenoble 38043, France
| | - Paul Zaslansky
- Department of Operative and Preventive Dentistry, Charité Universitätsmedizin Berlin, Aßmannshauser Straße 4-6, 14197 Berlin, Germany
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Fleck C, Burke M, Ganzosch G, Müller C, Currey JD, Zaslansky P. Breaking crown dentine in whole teeth: 3D observations of prevalent fracture patterns following overload. Bone 2020; 132:115178. [PMID: 31816420 DOI: 10.1016/j.bone.2019.115178] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 11/04/2019] [Accepted: 11/26/2019] [Indexed: 12/19/2022]
Abstract
Teeth with intact crowns rarely split or fracture, despite decades of cyclic loading and occasional unexpected overload. This is largely attributed to the presence of dentine, since cracking and fracture of enamel have been frequently reported. Dentine is similar to bone, comprising mineralised collagen fibres as a main constituent. Unlike cortical bone, however, where microcracking and damage arrest are essential for re/modelling and healing, dentine can neither remodel nor regenerate. This raises questions regarding the evolutionary benefits of toughening, leading to uncertainty whether cracks actually appear in dentine in situ. Here we study the notion that circumpulpal dentine is usually protected against, rather than damaged by severe overloads, even though it is not much more massive or stronger than it needs to be. To address this, we examined hydrated teeth still within whole jawbones of freshly-slaughtered skeletally mature pigs, mechanically loaded until fracture. Force displacement curves, optical and electron microscopy combined with 3D microstructural analysis by conventional micro-computed tomography (μCT) revealed mostly brittle fracture paths in circumpulpal crown dentine. Once overload cracks reach this mass of dentine they propagate rapidly along straight paths often parallel to the enamel flanks of the oblong shovel shaped premolars. We find infrequent signs of active toughening mechanisms with minimal crack diversion, ligament bridging and microcracking. When such toughening is seen, it mainly appears in softer dentine in the root, or near the dentine-enamel-junction (DEJ) in mantle dentine. We observed shear bands in overloaded circumpulpal dentine, due to mutual gliding of upper and lower segments. These shear bands are formed as periodic arrays of rotated dentine fragments. The 3D data consistently demonstrate the importance of the layered tooth structure, containing a stiff outer enamel shell, a soft sub-DEJ interlayer and a stiff circumpulpal dentine bulk, for deflecting cracks from splitting the tooth.
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Affiliation(s)
- Claudia Fleck
- Technische Universität Berlin, Chair of Materials Science and Engineering, Institute of Materials Science and Technologies, Str. des 17. Juni 136 - Sekr. EB13, 10623 Berlin, Germany.
| | - Martin Burke
- Technische Universität Berlin, Chair of Materials Science and Engineering, Institute of Materials Science and Technologies, Str. des 17. Juni 136 - Sekr. EB13, 10623 Berlin, Germany; Charité - Universitätsmedizin Berlin, Department for Operative and Preventive Dentistry, Aßmannshauser Str. 4-6, 14297 Berlin, Germany
| | - Gregor Ganzosch
- Technische Universität Berlin, Institute of Mechanics, Chair of Continuum Mechanics and Materials Theory, Einsteinufer 5 - Sekr. MS2, 10587 Berlin, Germany
| | - Cecilia Müller
- Technische Universität Berlin, Chair of Materials Science and Engineering, Institute of Materials Science and Technologies, Str. des 17. Juni 136 - Sekr. EB13, 10623 Berlin, Germany
| | - John D Currey
- The University of York, Department of Biology, Wentworth Way, York YO10 5DD, United Kingdom
| | - Paul Zaslansky
- Charité - Universitätsmedizin Berlin, Department for Operative and Preventive Dentistry, Aßmannshauser Str. 4-6, 14297 Berlin, Germany.
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Ng Y, Reddington LP, Berman A, Knowles JC, Nazhat SN, Gulabivala K. Viscoelastic and chemical properties of dentine after different exposure times to sodium hypochlorite, ethylenediaminetetraacetic acid and calcium hydroxide. AUST ENDOD J 2020; 46:234-243. [DOI: 10.1111/aej.12397] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/26/2020] [Indexed: 11/28/2022]
Affiliation(s)
- Yuan‐Ling Ng
- Unit of Endodontology Division of Restorative Dental Science UCL Eastman Dental Institute University College London London UK
| | - Liam P. Reddington
- Unit of Endodontology Division of Restorative Dental Science UCL Eastman Dental Institute University College London London UK
| | - Antony Berman
- Unit of Endodontology Division of Restorative Dental Science UCL Eastman Dental Institute University College London London UK
| | - Jonathan C. Knowles
- Division of Biomaterials & Tissue Engineering UCL Eastman Dental Institute University College London London UK
- Department of Nanobiomedical Science & Institute for Tissue Regeneration Engineering Dankook University Cheonan Korea
- Discoveries Centre for Regenerative and Precision Medicine UCL Campus London UK
| | - Showan N. Nazhat
- Department of Mining and Materials Engineering McGill University Montreal Quebec Canada
| | - Kishor Gulabivala
- Unit of Endodontology Division of Restorative Dental Science UCL Eastman Dental Institute University College London London UK
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Browne JT, Ng Y, Odlyha M, Gulabivala K, Bozec L. Influence of root maturity or periodontal involvement on dentinal collagen changes following Na
OC
l irrigation: an
ex vivo
study. Int Endod J 2019; 53:97-110. [DOI: 10.1111/iej.13200] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 08/05/2019] [Indexed: 11/29/2022]
Affiliation(s)
- J. T. Browne
- Unit of Endodontology Divisions of Restorative Dental Science UCL Eastman Dental Institute University College London LondonUK
| | - Y.‐L. Ng
- Unit of Endodontology Divisions of Restorative Dental Science UCL Eastman Dental Institute University College London LondonUK
| | - M. Odlyha
- Department of Biological Sciences Birkbeck University of LondonLondon UK
| | - K. Gulabivala
- Unit of Endodontology Divisions of Restorative Dental Science UCL Eastman Dental Institute University College London LondonUK
| | - L. Bozec
- Biomaterials & Tissue Engineering UCL Eastman Dental Institute University College London London UK
- Faculty of Dentistry University of Toronto Toronto Canada
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Karunanayake G, Ng YL, Knowles JC, Delgado AHS, Young AM, Gulabivala K, Nazhat SN. The effect of NaOCl and heat treatment on static and dynamic mechanical properties and chemical changes of dentine. J Mech Behav Biomed Mater 2019; 97:330-338. [PMID: 31153114 DOI: 10.1016/j.jmbbm.2019.05.042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 05/23/2019] [Accepted: 05/27/2019] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To determine the effect of heat on flexural strength (FS), maximum strain (MS), storage modulus (SM), tan delta (TD) and chemical changes through micro-Raman spectroscopy of dentine exposed to 2.5% NaOCl or saline. METHOD ology: Dentine bars were randomly allocated to 8 test groups. Half (groups 2,4,6,8) were treated with NaOCl for 20 min; the rest (groups 1,3,5,7) remained in saline. FS/MS were measured in groups 1-4 (n = 15) (3/4 were also heated to 200 °C & re-hydrated in saline). Micro-Raman spectroscopy was performed on bars from groups 1-4. SM/TD were measured in 5-8: in 5/6 (n = 10), repeated after heating (200 °C), then following re-hydration; in 7/8 (n = 3) after heating to 25-185 °C. RESULTS Increase in MS on heat and FS/MS on heat + NaOCl was not significant (P > 0.05). SM increased (P = 0.06) after heat treatment but reduced to initial state after rehydration (P = 0.03). TD did not change (P = 0.4) after heat (200 °C) treatment but rehydration increased it compared with pre-treatment state (P = 0.001). For dentine bars pre-treated with NaOCl, SM did not change (P = 0.6) after heat (200 °C) treatment or rehydration but TD significantly increased (P = 0.02) upon re-hydration compared with pre- (P=0.007), or post- (P = 0.03) heat-treatment states. SM and TD varied between 25-185 °C with no consistent trend amongst the NaOCl pre-treated bars. Micro-Raman only detected chemical changes following NaOCl treatment in the mineral phase. CONCLUSIONS Exposure of dentine bars to heat and NaOCl produced only moderate changes to quasi-static but marked changes to viscoelastic properties, which may be explained by chemical alterations.
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Affiliation(s)
- G Karunanayake
- Unit of Endodontology, Division of Restorative Dental Science, UCL Eastman Dental Institute, University College London, London, UK
| | - Y-L Ng
- Unit of Endodontology, Division of Restorative Dental Science, UCL Eastman Dental Institute, University College London, London, UK.
| | - J C Knowles
- Biomaterials & Tissue Engineering, UCL Eastman Dental Institute, University College London, London, UK; Institute of Tissue Regeneration Engineering (ITREN) and Department of NanobiomedicalScience and BK21 Plus NBM, Global Research Center for Regenerative Medicine, DankookUniversity, 518-10, Anseo-dong, Dongnam-gu, Cheonan, Chungcheongnam-do, South Korea; The Discoveries Centre for Regenerative and Precision Medicine, UCL Campus, GowerStreet, London, WC1E 6BT, UK
| | - A H S Delgado
- Biomaterials & Tissue Engineering, UCL Eastman Dental Institute, University College London, London, UK
| | - A M Young
- Biomaterials & Tissue Engineering, UCL Eastman Dental Institute, University College London, London, UK
| | - K Gulabivala
- Unit of Endodontology, Division of Restorative Dental Science, UCL Eastman Dental Institute, University College London, London, UK
| | - S N Nazhat
- Department of Mining and Materials Engineering, McGill University, Montreal, Qc, H3A 0C5, Canada
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Gulabivala K, Ng YL. Value of root-filled teeth in maintaining a functional dentition for life. Br Dent J 2019; 226:769-784. [DOI: 10.1038/s41415-019-0313-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Seknazi E, Pokroy B. Residual Strain and Stress in Biocrystals. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1707263. [PMID: 29766594 DOI: 10.1002/adma.201707263] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 03/07/2018] [Indexed: 06/08/2023]
Abstract
The development of residual strains within a material is a valuable engineering technique for increasing the material's strength and toughness. Residual strains occur naturally in some biominerals and are an important feature that is recently highlighted in biomineral studies. Here, manifestations of internal residual strains detected in biominerals are reviewed. The mechanisms by which they develop, as well as their impact on the biominerals' mechanical properties, are described. The question as to whether they can be utilized in multiscale strengthening and toughening strategies for biominerals is discussed.
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Affiliation(s)
- Eva Seknazi
- Department of Materials Science and Engineering and the Russell Berrie Nanotechnology Institute, Technion - Israel Institute of Technology, 32000, Haifa, Israel
| | - Boaz Pokroy
- Department of Materials Science and Engineering and the Russell Berrie Nanotechnology Institute, Technion - Israel Institute of Technology, 32000, Haifa, Israel
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Fratzl P, Speck T, Gorb S. Function by internal structure-preface to the special issue on bioinspired hierarchical materials. BIOINSPIRATION & BIOMIMETICS 2016; 11:060301. [PMID: 27897134 DOI: 10.1088/1748-3190/11/6/060301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Affiliation(s)
- Peter Fratzl
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Research Campus Golm, 14424 Potsdam, Germany
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