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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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2
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Sarna-Boś K, Skic K, Boguta P, Adamczuk A, Vodanovic M, Chałas R. Elemental mapping of human teeth enamel, dentine and cementum in view of their microstructure. Micron 2023; 172:103485. [PMID: 37271062 DOI: 10.1016/j.micron.2023.103485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 04/28/2023] [Accepted: 05/21/2023] [Indexed: 06/06/2023]
Abstract
This paper presents a detailed analysis to directly compare the morphology and chemistry of human tooth layers using advanced scanning electron microscopy (SEM) techniques together with supporting data from energy dispersive spectroscopy (EDS) measurements. The aim of this study was to visualise and evaluate the structural and microanalytical differences of the mineralised hard tissues of human teeth. The extracted sound teeth without any pathologies were divided into the following groups: incisors, canines, premolars, and molars. Tooth samples were broken vertically to preserve the primary structures and to visualise individual tooth tissues. Specimens were also used to find variations in the elemental composition of tissues for different tooth groups. The average thickness of the enamel in the tooth groups studied was 1.1 mm and the average width of the enamel prisms was 4.2 µm, with the highest values observed for molars. The analysis of the chemical composition of the enamel showed that Ca and P were among the predominant elements. The average dentine thickness was 1.87 mm, with the highest values determined for molars, and the lowest for canines. The width of the dentinal tubules was less than 2 µm, for molars being significantly smaller. The analysis of the chemical composition of the dentine showed the highest O content of the all tooth tissues analyzed, while a lower P and Ca content was observed compared to the enamel. The cementum thickness averaged 0.14 mm, with the highest values observed for molars and the lowest for incisors. The analysis of the chemical composition of the cementum showed the lowest average O and P content, and the highest average C and N content, compared to the enamel and the dentine. Increasingly accurate imaging and analysis of dental hard tissue structures provides the opportunity for multifactorial evaluation in terms of their clinical application.
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Affiliation(s)
- Katarzyna Sarna-Boś
- Department of Dental Prosthetics, Medical University of Lublin, Chodźki 6, 20-093 Lublin, Poland.
| | - Kamil Skic
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland
| | - Patrycja Boguta
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland
| | - Agnieszka Adamczuk
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland
| | - Marin Vodanovic
- Department of Dental Anthropology, University of Zagreb, School of Dental Medicine, University Hospital Centre Zagreb, Gundulićeva 5, HR-10000 Zagreb, Croatia; Department of Oral Medicine, Medical University of Lublin, Chodźki 6, 20-093 Lublin, Poland
| | - Renata Chałas
- Department of Oral Medicine, Medical University of Lublin, Chodźki 6, 20-093 Lublin, Poland
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Saha S, Roy S. Metallic Dental Implants Wear Mechanisms, Materials, and Manufacturing Processes: A Literature Review. MATERIALS (BASEL, SWITZERLAND) 2022; 16:ma16010161. [PMID: 36614500 PMCID: PMC9821388 DOI: 10.3390/ma16010161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 11/29/2022] [Accepted: 12/13/2022] [Indexed: 06/12/2023]
Abstract
OBJECTIVES From the treatment of damaged teeth to replacing missing teeth, dental biomaterials cover the scientific interest of many fields. Dental biomaterials are one of the implants whose effective life depends vastly on their material and manufacturing techniques. The purpose of this review is to summarize the important aspects for metallic dental implants from biomedical, mechanical and materials science perspectives. The review article will focus on five major aspects as mentioned below. Tooth anatomy: Maximizing the implant performance depends on proper understanding of human tooth anatomy and the failure behavior of the implants. Major parts from tooth anatomy including saliva characteristics are explored in this section. Wear mechanisms: The prominent wear mechanisms having a high impact on dental wear are abrasive, adhesive, fatigue and corrosion wear. To imitate the physiological working condition of dental implants, reports on the broad range of mastication force and various composition of artificial saliva have been included in this section, which can affect the tribo-corrosion behavior of dental implants. Dental implants classifications: The review paper includes a dedicated discussion on major dental implants types and their details for better understanding their applicability and characteristics. Implant materials: As of today, the most established dental implant materials are SS316L, cobalt chrome alloy and titanium. Detailed discussion on their material properties, microstructures, phase transformations and chemical compositions have been discussed here. Manufacturing techniques: In terms of different production methods, the lost wax casting method as traditional manufacturing is considered. Selective Laser Melting (SLM) and Directed Energy Deposition (DED) as additive manufacturing techniques (AM) have been discussed. For AM, the relationships between process-property-performance details have been explored briefly. The effectiveness of different manufacturing techniques was compared based on porosity distribution, mechanical and biomechanical properties. SUMMARY Despite having substantial research available on dental implants, there is a lack of systematic reviews to present a holistic viewpoint combining state-of-the-art from biomedical, mechanical, materials science and manufacturing perspectives. This review article attempts to combine a wide variety of analyzing approaches from those interdisciplinary fields to deliver deeper insights to researchers both in academia and industry to develop next-generation dental implants.
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Soukup JW, Hetzel SJ, Stone DS, Eriten M, Ploeg HL, Henak CR. Structure-function relationships in dog dentin. J Biomech 2022; 141:111218. [PMID: 35834939 PMCID: PMC10041743 DOI: 10.1016/j.jbiomech.2022.111218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 06/07/2022] [Accepted: 07/04/2022] [Indexed: 01/19/2023]
Abstract
Investigations into teeth mechanical properties provide insight into physiological functions and pathological changes. This study sought to 1) quantify the spatial distribution of elastic modulus, hardness and the microstructural features of dog dentin and to 2) investigate quantitative relationships between the mechanical properties and the complex microstructure of dog dentin. Maxillary canine teeth of 10 mature dogs were sectioned in the transverse and vertical planes, then tested using nanoindentation and scanning electron microscopy (SEM). Microstructural features (dentin area fraction and dentinal tubule density) and mechanical properties (elastic modulus and hardness) were quantified. Results demonstrated significant anisotropy and spatial variation in elastic modulus, hardness, dentin area fraction and tubule density. These spatial variations adhered to a consistent distribution pattern; hardness, elastic modulus and dentin area fraction generally decreased from superficial to deep dentin and from crown tip to base; tubule density generally increased from superficial to deep dentin. Poor to moderate correlations between microstructural features and mechanical properties (R2 = 0.032-0.466) were determined. The results of this study suggest that the other constituents may contribute to the mechanical behavior of mammalian dentin. Our results also present several remaining opportunities for further investigation into the roles of organic components (e.g., collagen) and mineral content on dentin mechanical behavior.
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Affiliation(s)
- Jason W Soukup
- Department of Surgical Sciences, University of Wisconsin-Madison, School of Veterinary Medicine, Madison, WI, USA.
| | - Scott J Hetzel
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA
| | - Donald S Stone
- Department of Materials Science and Engineering, University of Wisconsin-Madison, College of Engineering, Madison, WI, USA
| | - Melih Eriten
- Department of Mechanical Engineering, University of Wisconsin-Madison, College of Engineering, Madison, WI, USA
| | - Heidi-Lynn Ploeg
- Department of Mechanical Engineering, University of Wisconsin-Madison, College of Engineering, Madison, WI, USA; Department of Mechanics and Materials Engineering, Queen's University, Kingston, ON, Canada
| | - Corinne R Henak
- Department of Mechanical Engineering, University of Wisconsin-Madison, College of Engineering, Madison, WI, USA; Department of Orthopedics and Rehabilitation, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA
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Shohel M, Ray KK, Tivanski AV, McAdams NEB, Bancroft AM, Cramer BD, Forbes TZ. Nanomechanical variability in the early evolution of vertebrate dentition. Sci Rep 2022; 12:10203. [PMID: 35715512 PMCID: PMC9205932 DOI: 10.1038/s41598-022-14157-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 06/02/2022] [Indexed: 01/28/2023] Open
Abstract
Conodonts are an extinct group of primitive jawless vertebrates whose elements represent the earliest examples of a mineralized feeding apparatus in vertebrates. Their relative relationship within vertebrates remains unresolved. As teeth, conodont elements are not homologous with the dentition of vertebrates, but they exhibit similarities in mineralization, growth patterns, and function. They clearly represent an early evolutionary experiment in mineralized dentition and offer insight into analogous dentition in other groups. Unfortunately, analysis of functional performance has been limited to a handful of derived morphologies and material properties that may inform ecology and functional analysis are virtually unknown. Here we applied a nanoscale approach to evaluate material properties of conodont bioapatite by utilizing Atomic Force Microscopy (AFM) nanoindentation to determine Young's modulus (E) along multiple elements representing different ontogenetic stages of development in the coniform-bearing apparatus of Dapsilodus obliquicostatus. We observed extreme and systematic variation in E along the length (oral to aboral) of each element that largely mirrors the spatial and ontogenetic variability in the crystalline structure of these specimens. Extreme spatial variability of E likely contributed to breakage of elements that were regularly repaired/regrown in conodonts but later vertebrate dentition strategies that lacked the ability to repair/regrow likely required the development of different material properties to avoid structural failure.
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Affiliation(s)
- Mohammad Shohel
- grid.214572.70000 0004 1936 8294Department of Chemistry, University of Iowa, Iowa City, IA 52242 USA
| | - Kamal K. Ray
- grid.214572.70000 0004 1936 8294Department of Chemistry, University of Iowa, Iowa City, IA 52242 USA
| | - Alexei V. Tivanski
- grid.214572.70000 0004 1936 8294Department of Chemistry, University of Iowa, Iowa City, IA 52242 USA
| | - Neo E. B. McAdams
- grid.264784.b0000 0001 2186 7496Department of Geosciences, Texas Tech University, Lubbock, TX 79409 USA
| | - Alyssa M. Bancroft
- grid.214572.70000 0004 1936 8294Iowa Geological Survey, University of Iowa, Iowa City, IA 52242 USA
| | - Bradley D. Cramer
- grid.214572.70000 0004 1936 8294Department of Earth and Environmental Sciences, University of Iowa, Iowa City, IA 52242 USA
| | - Tori Z. Forbes
- grid.214572.70000 0004 1936 8294Department of Chemistry, University of Iowa, Iowa City, IA 52242 USA
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The power of weak ion-exchange resins assisted by amelogenin for natural remineralization of dental enamel: an in vitro study. Odontology 2022; 110:545-556. [PMID: 35147809 PMCID: PMC9170625 DOI: 10.1007/s10266-022-00688-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 01/20/2022] [Indexed: 10/28/2022]
Abstract
This study aims to develop an innovative dental product to remineralize dental enamel by a proper combination of ion-exchange resins as controlled release of mineral ions that form dental enamel, in the presence of amelogenin to guide the appropriate crystal growth. The novel product proposed consists of a combination of ion-exchange resins (weak acid and weak base) individually loaded with the remineralizing ions: Ca2+, PO43- and F-, also including Zn2+ in a minor amount as antibacterial, together with the protein amelogenin. Such cocktail provides onsite controlled release of the ions necessary for enamel remineralization due to the weak character of the resins and at the same time, a guiding tool for related crystal growth by the indicated protein. Amelogenin protein is involved in the structural development of natural enamel and takes a key role in controlling the crystal growth morphology and alignment at the enamel surface. Bovine teeth were treated by applying the resins and protein together with artificial saliva. Treated teeth were evaluated with nanoindentation, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The innovative material induces the dental remineralization creating a fluorapatite layer with a hardness equivalent to sound enamel, with the appropriate alignment of corresponding nanocrystals, being the fluorapatite more acid resistant than the original mineral. Our results suggest that the new product shows potential for promoting long-term remineralization leading to the inhibition of caries and protection of dental structures.
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Kumar A, Goyal A, Gauba K, Kapur A, Singh SK, Mehta SK. An evaluation of remineralised MIH using CPP-ACP and fluoride varnish: An in-situ and in-vitro study. Eur Arch Paediatr Dent 2022; 23:79-87. [PMID: 34057698 DOI: 10.1007/s40368-021-00630-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 05/05/2021] [Indexed: 12/16/2022]
Abstract
BACKGROUND Molar incisor hypomineralization (MIH) affected teeth have enamel with altered mineral content like decreased calcium and phosphorus and increased carbon content leading to porous enamel and subsequent post-eruptive breakdown. AIM An in situ study was conducted to evaluate and compare the effects of a Casein Phosphopeptide-Amorphous Calcium Phosphate (CPP-ACP)-based cream and fluoride varnish on the remineralization of MIH affected teeth. METHODS Enamel slabs were prepared from MIH affected teeth that had been extracted for various reasons and inserted in appliances of 30 participants who were undergoing interceptive orthodontic therapy. They were randomly divided into two groups using block randomization technique: Group A-daily single application of CPP-ACP cream (n = 15); Group B-professional application of fluoride varnishes every 3 months (n = 15). After 6 months of regular wear of the appliance, the enamel slabs were placed under Field Emission Scanning Microscope (FESEM) and Energy-Dispersive Spectroscopy (EDS) for evaluation of ultra structure and mineral content, respectively. RESULTS A significant increase in calcium and phosphorus content, and a decrease in carbon content was observed within the 6 months period, suggesting remineralization in both the groups. On comparing the Ca:P and Ca:C ratios, a significant increase in the Ca:C ratio was evident in the two groups. No significant difference was seen in the Ca:P ratio in the CPP-ACP group at six months. The inter-group comparison did not reveal any significant difference between the two groups either at baseline or at 6 months post-intervention. CONCLUSION Remineralization can be achieved in MIH affected teeth with the use of remineralizing agents.
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Affiliation(s)
- A Kumar
- Oral Health Sciences Center, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - A Goyal
- Oral Health Sciences Center, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - K Gauba
- Oral Health Sciences Center, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - A Kapur
- Oral Health Sciences Center, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - S K Singh
- Oral Health Sciences Center, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
| | - S K Mehta
- Punjab University, Chandigarh, India
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Qi H, Gao G, Wang H, Ma Y, Wang H, Wu S, Yu J, Wang Q. Mechanical properties, microstructure and chemical composition of naked mole rat incisors. BIOINSPIRED BIOMIMETIC AND NANOBIOMATERIALS 2021. [DOI: 10.1680/jbibn.21.00004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The naked mole rat incisors (NMRI) exhibit excellent mechanical properties, which make it a good prototype for design and fabrication of bionic mechanical systems and materials. In this work, we characterised the chemical composition, microstructure and mechanical properties of NMRI, and further compared these properties with the laboratory rat incisors (LRI). We found out that (i) Enamel and dentin are composed of organic matter, inorganic matter and water. The ratio of Ca/P in NMRI enamel is higher than that of LRI enamel. (ii) The dentin has a porous structure. The enamel has a three-dimensional reticular structure, which is more complex, regular and denser than the lamellar structure of LRI enamel. (iii) Enamel has anisotropy. Its longitudinal nano-hardness is greater than that of transverse nano-hardness, and both of them are higher than that of LRI enamel. Their nano-hardness and elastic modulus increase with the increase in distance from enamel-dentin boundary. The nano-hardness of dentin is smaller than that of enamel. The chemical composition and microstructure are considered to be the reasons for the excellent properties of NMRI. The chemical composition and unique microstructure can provide inspiration and guide for the design of bionic machinery and materials.
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Affiliation(s)
- Hongyan Qi
- College of Biological and Agricultural Engineering, Jilin University, Changchun, China; Key Laboratory of Bionic Engineering, Ministry of Education, Jilin University, Changchun, China
| | - Guixiong Gao
- College of Biological and Agricultural Engineering, Jilin University, Changchun, China; Ministry of Education, Key Laboratory of Bionic Engineering, Jilin University, Changchun, China
| | - Huixin Wang
- College of Biological and Agricultural Engineering, Jilin University, Changchun, China; Key Laboratory of Bionic Engineering, Ministry of Education, Jilin University, Changchun, China
| | - Yunhai Ma
- College of Biological and Agricultural Engineering, Jilin University, Changchun, China; Key Laboratory of Bionic Engineering, Jilin University, Changchun, China
| | - Hubiao Wang
- College of Biological and Agricultural Engineering, Jilin University, Changchun, China; Key Laboratory of Bionic Engineering, Ministry of Education, Jilin University, Changchun, China
| | - Siyang Wu
- College of Biological and Agricultural Engineering, Jilin University, Changchun, China; Key Laboratory of Bionic Engineering, Ministry of Education, Jilin University, Changchun, China
| | - Jiangtao Yu
- College of Biological and Agricultural Engineering, Jilin University, Changchun, China; Key Laboratory of Bionic Engineering, Ministry of Education, Jilin University, Changchun, China
| | - Qinghua Wang
- School of Mechanical Engineering, Southeast University, Nanjing, China
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Goyal K, Saha SG, Bhardwaj A, Saha MK, Bhapkar K, Paradkar S. A comparative evaluation of the effect of three different concentrations of in-office bleaching agents on microhardness and surface roughness of enamel - An in vitro study. Dent Res J (Isfahan) 2021; 18:49. [PMID: 34429869 PMCID: PMC8351945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 04/23/2020] [Accepted: 09/20/2020] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND To evaluate the changes in the micro-hardness and surface roughness of enamel treated with three different concentrations of in-office bleaching agents. MATERIALS AND METHODS In this in vitro study, 60 human incisors were divided into two groups (Group A and Group B). To obtain the baseline values, a Vickers tester was used to determine the surface microhardness in Group A, and a Surtronic tester was used for evaluation of surface roughness in Group B. Each group was then further subdivided into three subgroups and subjected to bleaching with Dash (Groups A1 and B1), Pola Office (Groups A2 and B2), and Opalescence Boost (Groups A3 and B3) containing 30%, 35%, and 40% hydrogen peroxide (HP), respectively. Samples were again subjected to testing to obtain the postbleaching values. Pre- and postbleaching data were analyzed by paired t-test. Intergroup comparison was carried out using one-way ANOVA (P ≤ 0.05). RESULTS A significant decrease in microhardness values was observed following bleaching in all the three groups, with Group A1 showing maximum percentage decrease (2.58%), followed by Group A2 (1.23%) and Group A3 (0.73%). Furthermore, an increase in surface roughness was observed following bleaching, with Group B1 showing maximum percentage increase (14.80%), followed by Group B2 (8.25%) and Group B3 (5.79%). However, there was no significant difference in either microhardness or surface roughness when comparing the postbleaching values among the three bleaching agents. CONCLUSION In-office bleaching agents may adversely affect the microhardness and roughness of enamel surface which are not related to the concentration of HP used.
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Affiliation(s)
- Khushboo Goyal
- Department of Conservative Dentistry and Endodontics, College of Dental Science and Hospital, Indore, Madhya Pradesh, India,Address for correspondence: Dr. Khushboo Goyal, Ganesh Gas Agency, Chick Santar, Morar, Gwalior, Madhya Pradesh, India. E-mail:
| | - Suparna Ganguly Saha
- Department of Conservative Dentistry and Endodontics, College of Dental Science and Hospital, Indore, Madhya Pradesh, India
| | - Anuj Bhardwaj
- Department of Conservative Dentistry and Endodontics, College of Dental Science and Hospital, Indore, Madhya Pradesh, India
| | - Mainak Kanti Saha
- Department of Prosthodontics, Crown and Bridge and oral Implantology, College of Dental Science and Hospital, Indore, Madhya Pradesh, India
| | - Kaustubh Bhapkar
- Department of Prosthodontics, Crown and Bridge and Oral Implantology, Jaipur Dental College, Jaipur, Rajasthan, India
| | - Shrija Paradkar
- Department of Conservative Dentistry and Endodontics, College of Dental Science and Hospital, Indore, Madhya Pradesh, India
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Olek A, Klimek L, Bołtacz-Rzepkowska E. Comparative scanning electron microscope analysis of the enamel of permanent human, bovine and porcine teeth. J Vet Sci 2021; 21:e83. [PMID: 33263230 PMCID: PMC7710455 DOI: 10.4142/jvs.2020.21.e83] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 09/09/2020] [Accepted: 09/14/2020] [Indexed: 12/03/2022] Open
Abstract
Background Bovine and porcine teeth are often used in in vitro experiments as substitutes of human teeth. Objectives The aim of the present study was to perform a comparative analysis of enamel morphology of permanent human, bovine and porcine teeth under the scanning electron microscope. Methods As many as 10 human, 10 bovine, and 10 porcine teeth were studied. All the teeth were sectioned and the halves were randomly divided into 2 groups according to the examined tissue (vestibular enamel at the mid-height of the dental crown and in the cervical area). Human and bovine enamel was etched for 15 sec and porcine enamel for 30 sec. The scanning electron microscope analysis was performed. The length and width of enamel prisms were determined with the “Met-Ilo” 1.1 computer program. Results All enamel samples revealed the same etching pattern—Silverstone's type 2. Bovine enamel showed a similar porosity and the amount of interprismatic enamel compared to human enamel while the amount and width of interprismatic enamel bands in porcine enamel were evidently greater. The shape of the porcine prisms was visually similar to human prisms, although dimensions were significantly different. However, bovine prisms differed in form and appeared to be distinctly elongated. Conclusions Reported findings indicate that the results of experimental studies carried out on bovine and porcine enamel should not be compared with the results obtained on human enamel.
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Affiliation(s)
- Aneta Olek
- Department of Conservative Dentistry, Medical University of Lodz, 92-217 Łódź, Poland.
| | - Leszek Klimek
- Institute of Materials Science and Engineering, University of Technology in Lodz, 90-924 Łódź, Poland
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Stifler CA, Jakes JE, North JD, Green DR, Weaver JC, Gilbert PUPA. Crystal misorientation correlates with hardness in tooth enamels. Acta Biomater 2021; 120:124-134. [PMID: 32711081 DOI: 10.1016/j.actbio.2020.07.037] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 07/14/2020] [Accepted: 07/17/2020] [Indexed: 01/31/2023]
Abstract
The multi-scale hierarchical structure of tooth enamel enables it to withstand a lifetime of damage without catastrophic failure. While many previous studies have investigated structure-function relationships in enamel, the effects of crystal misorientation on mechanical performance have not been assessed. To address this issue, in the present study, we review previously published polarization-dependent imaging contrast (PIC) maps of mouse and human enamel, and parrotfish enameloid, in which crystal orientations were measured and displayed in every 60-nm-pixel. By combining those previous results with the PIC maps of sheep enamel presented here we discovered that, in all enamel(oid)s, adjacent crystals are slightly misoriented, with misorientation angles in the 0°-30° range, and mean 2°-8°. Within this limited range, misorientation is positively correlated with literature hardness values, demonstrating an important structure-property relation, not previously identified. At greater misorientation angles 8°30°, this correlation is expected to reverse direction, but data from different non-enamel systems, with more diverse crystal misorientations, are required to determine if and where this occurs. STATEMENT OF SIGNIFICANCE: We identify a structure-function relationship in tooth enamels from different species: crystal misorientation correlates with hardness, contributing to the remarkable mechanical properties of enamel in diverse animals.
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Affiliation(s)
- Cayla A Stifler
- Department of Physics, University of Wisconsin, Madison, WI 53706, United States
| | - Joseph E Jakes
- Forest Biopolymers Science and Engineering, USDA Forest Service, Forest Products Laboratory, Madison, WI 53726, United States
| | - Jamie D North
- Department of Chemistry, Carleton College, Northfield, MN 55057, United States
| | - Daniel R Green
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA 02138, United States
| | - James C Weaver
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138, United States
| | - Pupa U P A Gilbert
- Department of Physics, University of Wisconsin, Madison, WI 53706, United States; Departments of Chemistry, Geoscience, Materials Science, University of Wisconsin, Madison, WI 53706, United States.
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12
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Goyal K, Saha S, Bhardwaj A, Saha M, Bhapkar K, Paradkar S. A comparative evaluation of the effect of three different concentrations of in-office bleaching agents on microhardness and surface roughness of enamel – An in vitro study. Dent Res J (Isfahan) 2021. [DOI: 10.4103/1735-3327.318944] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Abu-Saq Al Yami A, Al Qahtani S, Shokair N, Al Ghamdi M, Al Bouni R. Effect of home and in-office bleaching systems on the nanomechanical properties of tooth enamel. Saudi Dent J 2020; 32:343-348. [PMID: 33132662 PMCID: PMC7588502 DOI: 10.1016/j.sdentj.2019.10.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 10/20/2019] [Accepted: 10/21/2019] [Indexed: 11/02/2022] Open
Abstract
Objectives The purpose of this in vitro laboratory study was to gauge the nanomechanical properties of the tooth enamel surface using home and in-office bleaching products. Methods Thirty-six extracted lower lateral incisor teeth (sound and without caries, cracks or restorations) were selected. A silicone mould was used to affix the samples in resin after cutting away the roots. Next, the samples were indiscriminately divided into three treatment groups, i.e., 12 teeth in each study group (control, Opalescence Home, and Opalescence Boost), and treated according to their respective group procedures. Surface topography, nano-indentation, and visual analyses were performed. Data were examined statistically using one-way analysis of variance (p < 0.05). Results Both experimental bleaching products enhanced the surface roughness when compared to the samples in the control group. However, the control and Opalescence Boost groups showed insignificant differences. The lowest mean nanohardness (GPa) was observed in the Opalescence Boost group (1.56 GPa ± 0.68 GPa). In contrast, the highest mean nanohardness (GPa) was perceived in the control group (3.53 GPa ± 1.06 GPa). The modulus of elasticity was highly affected using Opalescence Boost (182.63 GPa ± 109.13 GPa) when compared to Control (322.69 GPa ± 168.24 GPa). On visual examination, pronounced roughness was observed in both the Opalescence Home and Opalescence Boost groups. Conclusion Both teeth whitening products damaged the enamel surface either by roughening the tooth surface or by affecting the nanomechanical properties. Therefore, teeth whitening products may be used, but with great caution.
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Affiliation(s)
| | - Saleh Al Qahtani
- Department of Restorative Dentistry, Riyadh Elm University, Riyadh, Saudi Arabia
| | - Nada Shokair
- Department of Restorative Dentistry, Riyadh Elm University, Riyadh, Saudi Arabia
| | - Mohammed Al Ghamdi
- Department of Restorative Dentistry, Riyadh Elm University, Riyadh, Saudi Arabia
| | - Roula Al Bouni
- Department of Restorative Dentistry, Riyadh Elm University, Riyadh, Saudi Arabia
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14
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Li P, Oh C, Kim H, Chen-Glasser M, Park G, Jetybayeva A, Yeom J, Kim H, Ryu J, Hong S. Nanoscale effects of beverages on enamel surface of human teeth: An atomic force microscopy study. J Mech Behav Biomed Mater 2020; 110:103930. [PMID: 32957225 DOI: 10.1016/j.jmbbm.2020.103930] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 05/17/2020] [Accepted: 06/10/2020] [Indexed: 11/17/2022]
Abstract
Dental erosion has become a prevalence disease and attracted increasing attention worldwide. In this research, we quantitatively evaluate the mechanical and morphological changes in the very early stages of softening and weakening of human enamel surfaces induced by soft drinks using atomic force microscopy (AFM). With an increase of the immersion time in soft drinks, we found a significant increase of surface roughness (Rq) of the enamel surface. The prismatic structure of enamel was clearly observed after a 1-h immersion in Coca-Cola®, which shows its strong erosion effect. According to the elastic modulus mapping images obtained by AFM, a considerable decrease of elastic modulus (E) of enamel surface has been found as the enamel surface structures are etched away by soft drinks. A high surface roughness of enamel will result in a high chance of cavities due to easier bacterial adhesion on rougher surface, while a drastic deterioration of the mechanical properties of the enamel will weaken its protection property. Our findings show the serious influence of acidic drinks on enamel surface at the very beginning stage of etching process, which is quite meaningful for people to prevent dental erosion and keep dental health.
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Affiliation(s)
- Panpan Li
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Daejeon, 34141, Republic of Korea
| | - Chungik Oh
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Daejeon, 34141, Republic of Korea
| | - Hongjun Kim
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Daejeon, 34141, Republic of Korea
| | - Melodie Chen-Glasser
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Daejeon, 34141, Republic of Korea
| | - Gun Park
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Daejeon, 34141, Republic of Korea
| | - Albina Jetybayeva
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Daejeon, 34141, Republic of Korea
| | - Jiwon Yeom
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Daejeon, 34141, Republic of Korea
| | - Hoon Kim
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Daejeon, 34141, Republic of Korea
| | - Jeongjae Ryu
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Daejeon, 34141, Republic of Korea
| | - Seungbum Hong
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Daejeon, 34141, Republic of Korea; KAIST Institute for NanoCentury (KINC), Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Daejeon, 34141, Republic of Korea.
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15
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Branco AC, Silva R, Jorge H, Santos T, Lorenz K, Polido M, Colaço R, Serro AP, Figueiredo-Pina CG. Tribological performance of the pair human teeth vs 3D printed zirconia: An in vitro chewing simulation study. J Mech Behav Biomed Mater 2020; 110:103900. [PMID: 32957205 DOI: 10.1016/j.jmbbm.2020.103900] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 05/04/2020] [Accepted: 05/30/2020] [Indexed: 11/17/2022]
Abstract
This study aims to evaluate the tribological performance of the pair human teeth/robocasted zirconia, with a special focus on the enamel wear mechanisms. Zirconia pieces produced by robocasting (RC) and unidirectional compression (UC) were compared in terms of crystalline structure, density, porosity, hardness and toughness. Chewing simulation tests were performed against human dental cusps. The cusps wear was quantified and the wear mechanisms identified. Although most of the properties of UC and RC samples are similar, differences were observed for surface roughness and porosity. Although the samples did not suffer wear, the antagonist cusps worn in a similar way. In conclusion, robocasting seems a promising technique to produce customized zirconia dental pieces, namely in what concerns the overall tribological behaviour.
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Affiliation(s)
- A C Branco
- CQE, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal; CDP2T, Escola Superior de Tecnologia de Setúbal, Instituto Politécnico de Setúbal, Setúbal, Portugal
| | - R Silva
- CQE, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - H Jorge
- Centro Tecnológico da Cerâmica e Do Vidro (CTCV), Coimbra, Portugal
| | | | - K Lorenz
- INESC-MN, IPFN, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - M Polido
- CiiEM, Escola Superior de Saúde Egas Moniz, Monte de Caparica, Portugal
| | - R Colaço
- IDMEC e Departamento de Engenharia Mecânica, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - A P Serro
- CQE, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal; CiiEM, Escola Superior de Saúde Egas Moniz, Monte de Caparica, Portugal.
| | - C G Figueiredo-Pina
- CDP2T, Escola Superior de Tecnologia de Setúbal, Instituto Politécnico de Setúbal, Setúbal, Portugal; CiiEM, Escola Superior de Saúde Egas Moniz, Monte de Caparica, Portugal; CeFEMA, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
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16
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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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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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Fannin LD, Guatelli-Steinberg D, Geissler E, Morse PE, Constantino PJ, McGraw WS. Enamel chipping in Taï Forest cercopithecids: Implications for diet reconstruction in paleoanthropological contexts. J Hum Evol 2020; 141:102742. [PMID: 32179368 DOI: 10.1016/j.jhevol.2020.102742] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 01/03/2020] [Accepted: 01/04/2020] [Indexed: 12/23/2022]
Abstract
Antemortem enamel chipping in living and fossil primates is often interpreted as evidence of hard-object feeding (i.e., 'durophagy'). Laboratory analyses of tooth fracture have modeled the theoretical diets and loading conditions that may produce such chips. Previous chipping studies of nonhuman primates tend to combine populations into species samples, despite the fact that species can vary significantly in diet across their ranges. Chipping is yet to be analyzed across population-specific species samples for which long-term dietary data are available. Here, we test the association between enamel chipping and diet in a community of cercopithecid primates inhabiting the Taï Forest, Ivory Coast. We examined fourth premolars and first molars (n = 867) from naturally deceased specimens of Cercocebus atys, Colobus polykomos, Piliocolobus badius,Procolobus verus, and three species of Cercopithecus. We found little support for a predictive relationship between enamel chipping and diet across the entire Taï monkey community. Cercocebus atys, a dedicated hard-object feeder, exhibited the highest frequencies of (1) chipped teeth and (2) chips of large size; however, the other monkey with a significant degree of granivory, Co. polykomos, exhibited the lowest chip frequency. In addition, primates with little evidence of mechanically challenging or hard-food diets-such as Cercopithecus spp., Pi. badius, and Pr. verus-evinced higher chipping frequencies than expected. The equivocal and stochastic nature of enamel chipping in the Taï monkeys suggests nondietary factors contribute significantly to chipping. A negative association between canopy preference and chipping suggests a role of exogenous particles in chip formation, whereby taxa foraging closer to the forest floor encounter more errant particulates during feeding than species foraging in higher strata. We conclude that current enamel chipping models may provide insight into the diets of fossil primates, but only in cases of extreme durophagy. Given the role of nondietary factors in chip formation, our ability to reliably reconstruct a range of diets from a gradient of chipping in fossil taxa is likely weak.
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Affiliation(s)
- Luke D Fannin
- Department of Anthropology, 4064 Smith Laboratory, The Ohio State University, 174 West 18th Avenue, Columbus, OH, 43210-1106, USA.
| | - Debbie Guatelli-Steinberg
- Department of Anthropology, 4064 Smith Laboratory, The Ohio State University, 174 West 18th Avenue, Columbus, OH, 43210-1106, USA
| | - Elise Geissler
- Department of Anthropology, University of Florida, Gainesville, FL, 32611-7305, USA
| | - Paul E Morse
- Department of Evolutionary Anthropology, Duke University, Durham, NC, 27708-9976, USA; Florida Museum of Natural History, University of Florida, Gainesville, FL, 32611-7800, USA
| | - Paul J Constantino
- Department of Biology, Saint Michael's College, Colchester, VT, 05439, USA
| | - W Scott McGraw
- Department of Anthropology, 4064 Smith Laboratory, The Ohio State University, 174 West 18th Avenue, Columbus, OH, 43210-1106, USA
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Zhu J, Luo D, Rong Q, Wang X. Effect of biomimetic material on stress distribution in mandibular molars restored with inlays: a three-dimensional finite element analysis. PeerJ 2019; 7:e7694. [PMID: 31565585 PMCID: PMC6745185 DOI: 10.7717/peerj.7694] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 08/19/2019] [Indexed: 11/28/2022] Open
Abstract
Background Although biomimetic material has become increasingly popular in dental cosmetology nowadays, it remains unclear how it would affect the restored teeth during chewing. It is necessary to study the influence of biomimetic material on stress distribution in the restored teeth. Methods Eight three-dimensional finite element (FE) models were constructed and divided into two groups. Group 1 included the FE model of intact molar, and the FE models of inlay-restored molars fabricated from IPS e.max CAD, Lava Ultimate and biomimetic materials individually. Enamel was considered a homogeneous material. Group 2 included the FE models of intact molar and molars restored with inlays using IPS e.max CAD, Lava Ultimate and biomimetic materials individually, considering enamel as an inhomogeneous material. Results In Group 1, compared with that in the intact molar, the maximum tensile stress (MTS) in the occlusal grooves decreased in the inlay-restored molars fabricated from IPS e.max CAD and was concentrated on the cavity floor at the buccal side in the inner dentin around inlay. When Lava Ultimate was selected, MTS decreased in the occlusal grooves and on the cavity floor but increased in the lateral walls. In the restored molar using biomimetic material, the MTS on the cavity floor was distributed more evenly than that in the molar using IPS e.max CAD, and no obvious changes were noted in the lateral walls. The same changes were observed in Group 2. No differences in the stress distribution pattern were noted among the FE models in Groups 1 and 2. Conclusions Molars restored with inlays fabricated from biomimetic material exhibit a more uniform stress distribution in the dentin around restoration. The consideration of enamel as a homogeneous tissue is acceptable for analyzing the maximum principal stress distribution in the inlay-restored molar.
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Affiliation(s)
- Junxin Zhu
- Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing, China
| | - Danmei Luo
- Department of Mechanics and Engineering Science, Peking University, Beijing, China
| | - Qiguo Rong
- Department of Mechanics and Engineering Science, Peking University, Beijing, China
| | - Xiaoyan Wang
- Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing, China
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Hesse B, Stier D, Cotte M, Forien JB, Zaslansky P. Polarization induced contrast X-ray fluorescence at submicrometer resolution reveals nanometer apatite crystal orientations across entire tooth sections. BIOMEDICAL OPTICS EXPRESS 2019; 10:18-28. [PMID: 30775080 PMCID: PMC6363201 DOI: 10.1364/boe.10.000018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 10/11/2018] [Accepted: 11/02/2018] [Indexed: 05/28/2023]
Abstract
For biomedical research, successful imaging of calcified microstructures often relies on absorption differences between features, or on employing dies with selective affinity to areas of interest. When texture is concerned, e.g. for crystal orientation studies, polarization induced contrast is of particular interest. This requires sufficient interaction of the incoming radiation with the volume of interest in the sample to produce orientation-based contrast. Here we demonstrate polarization induced contrast at the calcium K-edge using submicron sized monochromatic synchrotron X-ray beams. We exploit the orientation dependent subtle absorption differences of hydroxyl-apatite crystals in teeth, with respect to the polarization field of the beam. Interaction occurs with the fully mineralized samples, such that differences in density do not contribute to the contrast. Our results show how polarization induced contrast X-ray fluorescence mapping at specific energies of the calcium K-edge reveals the micrometer and submicrometer crystal arrangements in human tooth tissues. This facilitates combining both high spatial resolution and large fields of view, achieved in relatively short acquisition times in reflection geometry. In enamel we observe the varying crystal orientations of the micron sized prisms exposed on our prepared surface. We easily reproduce crystal orientation maps, typically observed in polished thin sections. We even reveal maps of submicrometer mineralization fronts in spherulites in intertubular dentine. This Ca K-edge polarization sensitive method (XRF-PIC) does not require thin samples for transmission nor extensive sample preparation. It can be used on both fresh, moist samples as well as fossilized samples where the information of interests lies in the crystal orientations and where the crystalline domains extend several micrometers beneath the exposed surface.
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Affiliation(s)
- Bernhard Hesse
- European Synchrotron Radiation Facility, Grenoble, France
- Xploraytion GmbH, Berlin, Germany
| | - Deborah Stier
- European Synchrotron Radiation Facility, Grenoble, France
- B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, Germany
| | - Marine Cotte
- European Synchrotron Radiation Facility, Grenoble, France
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR 8220, Laboratoire d'Archéologie Moléculaire et Structurale (LAMS), Paris, France
| | - Jean-Baptiste Forien
- Materials Science Division, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - Paul Zaslansky
- Department for Operative and Preventive Dentistry, Charité - Universitätsmedizin Berlin, Aßmannshauser Str. 4-6 Berlin 14197, Germany
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21
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Min J, Yu P, Xu Z, Li Z, Zhang Q, Yu H, Gao S. Investigation on the Gradient Nanomechanical Behavior of Dental Fluorosis Enamel. NANOSCALE RESEARCH LETTERS 2018; 13:347. [PMID: 30377848 PMCID: PMC6207606 DOI: 10.1186/s11671-018-2768-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 10/18/2018] [Indexed: 02/05/2023]
Abstract
This study aims to investigate the gradient nanomechanical behavior of dental fluorosis enamel and provide appropriate selection criteria for restorative materials. The nanomechanical properties of the outer, middle, and inner layers of normal tooth enamel, mild dental fluorosis enamel, and severe dental fluorosis enamel were tested by nanoindentation under an applied load of 2000 μN and holding time of 30 s. The nanotribological properties were then evaluated through nanoscratch tests under an applied load of 1000 μN. In addition, the nanotribological property of the outer layer of dental fluorosis enamel was compared with that of four restorative materials, namely, lithium disilicate glass-ceramic (IPS e.max CAD), polymer-infiltrated-ceramic network (PICN), composite resin block (Lava™ ultimate), and conventional composite resin (Fltek™ Z350XT). The nanohardness and elastic modulus of mild dental fluorosis enamel increased from the outer to the middle layers and then decreased from the middle to the inner layers. By contrast, the changed displacement, friction coefficient, and nanoscratch depth and width decreased from the outer to the middle layers and then increased from the middle to the inner layers. In severe dental fluorosis enamel, nanohardness and elastic modulus increased from the outer to the inner layers, but the changed displacement, friction coefficient, and nanoscratch depth and width decreased from the outer to the inner layers. The nanoscratch depth and width of Lava™ ultimate were similar to those of the outer layer of the mild dental fluorosis enamel. The gradient nanomechanical behavior of dental fluorosis enamel significantly differed from that of normal tooth enamel. Dental materials with a wear resistance similar to that of the opposing enamel are a good choice for restoring dental fluorosis (trial registration: WCHSIRB-D-2014-126, registered 25 December 2014).
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Affiliation(s)
- Jie Min
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Ping Yu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Zhou Xu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Zhi Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Qianqian Zhang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Haiyang Yu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Shanshan Gao
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
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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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Kaiser TM, Braune C, Kalinka G, Schulz-Kornas E. Nano-indentation of native phytoliths and dental tissues: implications for herbivore-plant combat and dental wear proxies. EVOLUTIONARY SYSTEMATICS 2018. [DOI: 10.3897/evolsyst.2.22678] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Tooth wear induced by abrasive particles is a key process affecting dental function and life expectancy in mammals. Abrasive particles may be plant endogenous opal phytoliths, exogene wind-blown quartz dust or rain borne mineral particles ingested by mammals. Nano-indentation hardness of abrasive particles and dental tissues is a significant yet not fully established parameter of this tribological system. We provide consistent nano-indentation hardness data for some of the major antagonists in the dental tribosystem (tooth enamel, tooth dentine and opaline phytoliths from silica controlled cultivation). All indentation data were gathered from native tissues under stable and controlled conditions and thus maximize comparability to natural systems. Here we show that native (hydrated) wild boar enamel exceeds any hardness measures known for dry herbivore tooth enamel by at least 3 GPa. The native tooth enamel is not necessarily softer then environmental quartz grit, although there is little overlap. The native hardness of the tooth enamel exceeds that of any silica phytolith hardness recently published. Further, we find that native reed phytoliths equal native suine dentine in hardness, but does not exceed native suine enamel. We also find that native suine enamel is significantly harder than dry enamel and dry phytoliths are harder than native phytoliths. Our data challenge the claim that the culprit of tooth wear may be the food we chew, but suggest instead that wear may relates more to exogenous than endogenous abrasives.
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Warkentin M, Freyse C, Specht O, Behrend D, Maletz R, Janda R, Ottl P. Correlation of ultrasound microscopy and Vickers hardness measurements of human dentin and enamel - A pilot study. Dent Mater 2018; 34:1036-1040. [PMID: 29678330 DOI: 10.1016/j.dental.2018.03.020] [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: 02/18/2018] [Accepted: 03/24/2018] [Indexed: 10/17/2022]
Abstract
OBJECTIVE To investigate if Vickers microhardness of dentin and enamel correlated with acoustic velocity c(l) or acoustic reflection from the sample's top (amplitude). METHODS Eight transversal sections of a sound human tooth were investigated with scanning acoustic microscopy (SAM) and Vickers microhardness measurements. Longitudinal acoustic velocity c(l), amplitude and microhardness MHV were evaluated and for each c(l) test point corresponding amplitude and MHV were linearly interpolated and graphically analyzed. Spearman rank order correlation (rS) was calculated (p<0.05). RESULTS c(l) was predominantly 6100-7000ms-1 in enamel and 3800-4600ms-1 in dentin and correlated significantly with MHV with 27-420 in enamel and 20-90 in dentin (rs=0,57). Amplitudes significantly correlated with MHV, too, but even better (rs=0,77). SIGNIFICANCE Acoustic velocity and amplitudes were appropriate to detect microhardness differences of dentin and enamel and certain value ranges of both could be assigned to certain MHV ranges. Further research is needed to differentiate more precisely between the different hard tooth tissues.
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Affiliation(s)
- Mareike Warkentin
- Department of Materials Science and Medical Engineering, Friedrich-Barnewitz-Strasse 4, 18119 Rostock, University of Rostock, Germany
| | - Cora Freyse
- Department of Prosthodontics and Materials Science, Strempelstrasse 13, 18057 Rostock, University of Rostock, Germany
| | - Olaf Specht
- Institute of ImplantTechnology and Biomaterials e.V., Rostock, Friedrich-Barnewitz-Strasse 4, 18119 Rostock, Germany
| | - Detlef Behrend
- Department of Materials Science and Medical Engineering, Friedrich-Barnewitz-Strasse 4, 18119 Rostock, University of Rostock, Germany
| | - Reinhard Maletz
- Department of Materials Science and Medical Engineering, Friedrich-Barnewitz-Strasse 4, 18119 Rostock, University of Rostock, Germany
| | - Ralf Janda
- Dept. of Operative and Preventive Dentistry and Endodontics, Centre of Dentistry, Medical Faculty, Heinrich-Heine-University, Moorenstraße 5, Geb. 18.13, D-40225 Düsseldorf, Germany.
| | - Peter Ottl
- Department of Prosthodontics and Materials Science, Strempelstrasse 13, 18057 Rostock, University of Rostock, Germany
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Anastasiou A, Strafford S, Thomson C, Gardy J, Edwards T, Malinowski M, Hussain S, Metzger N, Hassanpour A, Brown C, Brown A, Duggal M, Jha A. Exogenous mineralization of hard tissues using photo-absorptive minerals and femto-second lasers; the case of dental enamel. Acta Biomater 2018; 71:86-95. [PMID: 29462711 DOI: 10.1016/j.actbio.2018.02.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 02/05/2018] [Accepted: 02/09/2018] [Indexed: 11/29/2022]
Abstract
A radical new methodology for the exogenous mineralization of hard tissues is demonstrated in the context of laser-biomaterials interaction. The proposed approach is based on the use of femtosecond pulsed lasers (fs) and Fe3+-doped calcium phosphate minerals (specifically in this work fluorapatite powder containing Fe2O3 nanoparticles (NP)). A layer of the synthetic powder is applied to the surface of eroded bovine enamel and is irradiated with a fs laser (1040 nm wavelength, 1 GHz repetition rate, 150 fs pulse duration and 0.4 W average power). The Fe2O3 NPs absorb the light and may act as thermal antennae, dissipating energy to the vicinal mineral phase. Such a photothermal process triggers the sintering and densification of the surrounding calcium phosphate crystals thereby forming a new, dense layer of typically ∼20 μm in thickness, which is bonded to the underlying surface of the natural enamel. The dispersed iron oxide NPs, ensure the localization of temperature excursion, minimizing collateral thermal damage to the surrounding natural tissue during laser irradiation. Simulated brushing trials (pH cycle and mechanical force) on the synthetic layer show that the sintered material is more acid resistant than the natural mineral of enamel. Furthermore, nano-indentation confirms that the hardness and Young's modulus of the new layers are significantly more closely matched to enamel than current restorative materials used in clinical dentistry. Although the results presented herein are exemplified in the context of bovine enamel restoration, the methodology may be more widely applicable to human enamel and other hard-tissue regenerative engineering. STATEMENT OF SIGNIFICANCE In this work we provide a new methodology for the mineralisation of dental hard tissues using femtosecond lasers and iron doped biomaterials. In particular, we demonstrate selective laser sintering of an iron doped fluorapatite on the surface of eroded enamel under low average power and mid-IR wavelength and the formation of a new layer to substitute the removed material. The new layer is evaluated through simulated brushing trials and nano-indentation. From the results we can conclude that is more acid resistant than natural enamel while, its mechanical properties are superior to that of current restorative materials. To the best of our knowledge this is the first time that someone demonstrated, laser sintering and bonding of calcium phosphate biomaterials on hard tissues. Although we here we discuss the case of dental enamel, similar approach can be adopted for other hard tissues, leading to new strategies for the fixation of bone/tooth defects.
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Kallistová A, Skála R, Šlouf M, Čejchan P, Matulková I, Horáček I. Enamel apatite crystallinity significantly contributes to mammalian dental adaptations. Sci Rep 2018; 8:5544. [PMID: 29615748 PMCID: PMC5882951 DOI: 10.1038/s41598-018-23826-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 03/20/2018] [Indexed: 11/09/2022] Open
Abstract
The monophyodont molar teeth, prismatic enamel and the complexity of enamel microarchitecture are regarded as essential dental apomorphies of mammals. As prominent background factors of feeding efficiency and individual longevity these characters are crucial components of mammalian adaptive dynamics. Little is known, however, to which degree these adaptations are influenced by the crystallographic properties of elementary hydroxyapatite crystallites, the only inorganic component of enamel. In a miniature pig where individual molars differ significantly in duration of their development and in enamel resistance to attrition stress, we found highly significant differences between the molars in the size of crystallites, amount of microstrain, crystallinity and in enamel stiffness and elasticity, all clearly scaled with the duration of tooth calcification. The same pattern was found also in red deer bearing different molar type. The results suggest that the prolongation of tooth development is associated with an increase of crystallinity, i.e. the atomic order of enamel hydroxyapatite, an obvious component of micromechanical property of mature enamel. This relation could contribute to prolongation of dental development, characteristic of mammals in general. The aspects of enamel crystallinity, omitted in previous studies on mammalian and vertebrate dental evolution, are to be taken in account in these topics.
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Affiliation(s)
- Anna Kallistová
- Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Albertov 6, Prague, 2, Czech Republic. .,Institute of Geology of the CAS, v.v.i., Rozvojová 269, Prague, 6, Czech Republic.
| | - Roman Skála
- Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Albertov 6, Prague, 2, Czech Republic.,Institute of Geology of the CAS, v.v.i., Rozvojová 269, Prague, 6, Czech Republic
| | - Miroslav Šlouf
- Institute of Macromolecular Chemistry of the CAS v.v.i., Heyrovského náměstí 2, Prague, 6, Czech Republic
| | - Petr Čejchan
- Institute of Geology of the CAS, v.v.i., Rozvojová 269, Prague, 6, Czech Republic
| | - Irena Matulková
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030/8, Prague, 2, Czech Republic
| | - Ivan Horáček
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, Prague, 2, Czech Republic.
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Deang JF, Persons AK, Oppedal AL, Rhee H, Moser RD, Horstemeyer MF. Structure, property, and function of sheepshead (Archosargus probatocephalus) teeth. Arch Oral Biol 2018; 89:1-8. [PMID: 29407634 DOI: 10.1016/j.archoralbio.2018.01.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 12/14/2017] [Accepted: 01/17/2018] [Indexed: 11/30/2022]
Abstract
OBJECTIVES This paper studies A. probatocephalus teeth and investigates the mechanical properties and chemical composition of the enameloid and dentin. DESIGN Nanoindentation tests with a max load of 1000 μN and X-ray Energy Dispersive Spectroscopy (EDS) were performed along the diameter of the polished sample. Microstructural analysis of the dentin tubules was performed from SEM images. RESULTS From nanoindentation testing, the dentin of the sheepshead teeth has a nanoindentation hardness of 0.89 ± 0.21 (mean ± S.D.) GPa and a reduced Young's modulus of 23.29 ± 5.30 GPa. The enameloid of A. probatocephalus has a hardness of 4.36 ± 0.44 GPa and a mean reduced Young's modulus of 98.14 ± 6.91 GPa. Additionally, nanoindentation tests showed that the enameloid's hardness and modulus increased closer to the surface of the tooth. X-ray Energy Dispersive Spectroscopy (EDS) data further suggests that the gradient may be a result of the wt% fluoride within the enameloid, where an increase in fluoride results in an increase in reduced Young's modulus and hardness. CONCLUSION The microstructural characterization of the number density and area of the dentin tubules were used to address the porosity effect in the dentin to achieve the experimentally validated microhardness. The mechanical properties of the sheepshead teeth were also compared with previous nanoindentation tests from other aquatic species. The sheepshead teeth exhibit a greater reduced Young's modulus and hardness compared to shark and piranha teeth.
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Affiliation(s)
- J F Deang
- Department of Mechanical Engineering, Mississippi State University, Mississippi State, MS 39762, USA; Center for Advanced Vehicular Systems, Mississippi State University, Mississippi State, MS 39762, USA.
| | - A K Persons
- Department of Mechanical Engineering, Mississippi State University, Mississippi State, MS 39762, USA; Center for Advanced Vehicular Systems, Mississippi State University, Mississippi State, MS 39762, USA
| | - A L Oppedal
- Center for Advanced Vehicular Systems, Mississippi State University, Mississippi State, MS 39762, USA
| | - H Rhee
- Department of Mechanical Engineering, Mississippi State University, Mississippi State, MS 39762, USA; Center for Advanced Vehicular Systems, Mississippi State University, Mississippi State, MS 39762, USA
| | - R D Moser
- US Army Engineer Research and Development Center, Geotechnical and Structures Laboratory, 3909 Halls Ferry Rd., Vicksburg, MS 39180, USA
| | - M F Horstemeyer
- Department of Mechanical Engineering, Mississippi State University, Mississippi State, MS 39762, USA; Center for Advanced Vehicular Systems, Mississippi State University, Mississippi State, MS 39762, USA
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Prajapati S, Ruan Q, Mukherjee K, Nutt S, Moradian-Oldak J. The Presence of MMP-20 Reinforces Biomimetic Enamel Regrowth. J Dent Res 2017; 97:84-90. [PMID: 28846464 DOI: 10.1177/0022034517728504] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Biomimetic synthesis of artificial enamel is a promising strategy for the prevention and restoration of defective enamel. We have recently reported that a hydrogel system composed of chitosan-amelogenin (CS-AMEL) and calcium phosphate is effective in forming an enamel-like layer that has a seamless interface with natural tooth surfaces. Here, to improve the mechanical system function and to facilitate the biomimetic enamel regrowth, matrix metalloproteinase-20 (MMP-20) was introduced into the CS-AMEL hydrogel. Inspired by our recent finding that MMP-20 prevents protein occlusion inside enamel crystals, we hypothesized that addition of MMP-20 to CS-AMEL hydrogel could reinforce the newly grown layer. Recombinant human MMP-20 was added to the CS-AMEL hydrogel to cleave full-length amelogenin during the growth of enamel-like crystals on an etched enamel surface. The MMP-20 proteolysis of amelogenin was studied, and the morphology, composition, and mechanical properties of the newly grown layer were characterized. We found that amelogenin was gradually degraded by MMP-20 in the presence of chitosan. The newly grown crystals in the sample treated with MMP-20-CS-AMEL hydrogel showed more uniform orientation and greater crystallinity than the samples treated with CS-AMEL hydrogel without MMP-20. Stepwise processing of amelogenin by MMP-20 in the CS-AMEL hydrogel prevented undesirable protein occlusion within the newly formed crystals. As a result, both the modulus and hardness of the repaired enamel were significantly increased (1.8- and 2.4-fold, respectively) by the MMP-20-CS-AMEL hydrogel. Although future work is needed to further incorporate other enamel matrix proteins into the system, this study brings us one step closer to biomimetic enamel regrowth.
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Affiliation(s)
- S Prajapati
- 1 Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - Q Ruan
- 1 Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - K Mukherjee
- 1 Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
| | - S Nutt
- 2 Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, USA
| | - J Moradian-Oldak
- 1 Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA
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Thiery G, Lazzari V, Ramdarshan A, Guy F. Beyond the Map: Enamel Distribution Characterized from 3D Dental Topography. Front Physiol 2017; 8:524. [PMID: 28785226 PMCID: PMC5519568 DOI: 10.3389/fphys.2017.00524] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 07/07/2017] [Indexed: 11/24/2022] Open
Abstract
Enamel thickness is highly susceptible to natural selection because thick enamel may prevent tooth failure. Consequently, it has been suggested that primates consuming stress-limited food on a regular basis would have thick-enameled molars in comparison to primates consuming soft food. Furthermore, the spatial distribution of enamel over a single tooth crown is not homogeneous, and thick enamel is expected to be more unevenly distributed in durophagous primates. Still, a proper methodology to quantitatively characterize enamel 3D distribution and test this hypothesis is yet to be developed. Unworn to slightly worn upper second molars belonging to 32 species of anthropoid primates and corresponding to a wide range of diets were digitized using high resolution microcomputed tomography. In addition, their durophagous ability was scored from existing literature. 3D average and relative enamel thickness were computed based on the volumetric reconstruction of the enamel cap. Geometric estimates of their average and relative enamel-dentine distance were also computed using 3D dental topography. Both methods gave different estimations of average and relative enamel thickness. This study also introduces pachymetric profiles, a method inspired from traditional topography to graphically characterize thick enamel distribution. Pachymetric profiles and topographic maps of enamel-dentine distance are combined to assess the evenness of thick enamel distribution. Both pachymetric profiles and topographic maps indicate that thick enamel is not significantly more unevenly distributed in durophagous species, except in Cercopithecidae. In this family, durophagous species such as mangabeys are characterized by an uneven thick enamel and high pachymetric profile slopes at the average enamel thickness, whereas non-durophagous species such as colobine monkeys are not. These results indicate that the distribution of thick enamel follows different patterns across anthropoids. Primates might have developed different durophagous strategies to answer the selective pressure exerted by stress-limited food.
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Affiliation(s)
- Ghislain Thiery
- iPHEP UMR Centre National de la Recherche Scientifique 7262 INEE, Université de PoitiersPoitiers, France
- School of Sociology and Anthropology, Sun Yat-Sen UniversityGuangzhou, China
| | - Vincent Lazzari
- iPHEP UMR Centre National de la Recherche Scientifique 7262 INEE, Université de PoitiersPoitiers, France
| | - Anusha Ramdarshan
- iPHEP UMR Centre National de la Recherche Scientifique 7262 INEE, Université de PoitiersPoitiers, France
| | - Franck Guy
- iPHEP UMR Centre National de la Recherche Scientifique 7262 INEE, Université de PoitiersPoitiers, France
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Sivapriya E, Sridevi K, Periasamy R, Lakshminarayanan L, Pradeepkumar AR. Remineralization ability of sodium fluoride on the microhardness of enamel, dentin, and dentinoenamel junction: An in vitro study. J Conserv Dent 2017; 20:100-104. [PMID: 28855756 PMCID: PMC5564234 DOI: 10.4103/jcd.jcd_353_16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Aim: Dental tissues such as enamel, dentinoenamel junction (DEJ), dentin, and root dentin can react differently to demineralization and remineralization. The aim of this study was to evaluate the remineralization ability of sodium fluoride on the microhardness of enamel, dentin, and dentinoenamel junction. Materials and Methods: Ten extracted third molar teeth were sectioned mesiodistally to form control and test groups. For the test group, initial demineralization was done with acetic acid for 24 h followed by remineralization for 28 days by application of sodium fluoride (226 ppm) for 2 min twice a day. Vickers microhardness test was done to control and test groups at different sites after initial demineralization and on the 3rd, 5th, 7th, 14th, and 28th day of remineralization. Statistical Analysis Used: Data were analyzed with one-way analysis of variance and post hoc test with a significance level of P < 0.001 with SPSS (21) software. Results: Microhardness values in the demineralization group were significantly lower than controls (P < 0.001). Evaluation of remineralization samples showed that microhardness similar to control values were achieved at the 3rd day in root predentin and on the 5th day in coronal dentin and coronal predentin. On the 7th day, remineralization coronal predentin was significantly higher than the control (P < 0.001). On the 14th day, DEJ axial zone and root dentin were similar to control and coronal dentin was significantly higher than the control (P < 0.001). Enamel was similar to control on the 28th day. Microhardness of DEJ-cusp tip and DEJ-center of the fissure was significantly lower than control even at the 28th day (P < 0.001). Conclusion: Long-term repeated application of sodium fluoride (226 ppm) can improve the microhardness of demineralized dental tissues on enamel, dentin, and DEJ-axial zone, except in the DEJ-cusp tip and DEJ-center of fissure.
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Affiliation(s)
- Elangovan Sivapriya
- Department of Conservative Dentistry and Endodontics, Thai Moogambigai Dental College and Hospital, Dr. M. G. R. University, Educational and Research Institute, Chennai, Tamil Nadu, India
| | - Krishnamoorthy Sridevi
- Department of Conservative Dentistry and Endodontics, Thai Moogambigai Dental College and Hospital, Dr. M. G. R. University, Educational and Research Institute, Chennai, Tamil Nadu, India
| | - Ravishankar Periasamy
- Department of Conservative Dentistry and Endodontics, Thai Moogambigai Dental College and Hospital, Dr. M. G. R. University, Educational and Research Institute, Chennai, Tamil Nadu, India
| | - Lakshmikanthanbharathi Lakshminarayanan
- Department of Conservative Dentistry and Endodontics, Thai Moogambigai Dental College and Hospital, Dr. M. G. R. University, Educational and Research Institute, Chennai, Tamil Nadu, India
| | - Angambakkam Rajasekaran Pradeepkumar
- Department of Conservative Dentistry and Endodontics, Thai Moogambigai Dental College and Hospital, Dr. M. G. R. University, Educational and Research Institute, Chennai, Tamil Nadu, India
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Weng Z, Liu Z, Ritchie R, Jiao D, Li D, Wu H, Deng L, Zhang Z. Giant panda׳s tooth enamel: Structure, mechanical behavior and toughening mechanisms under indentation. J Mech Behav Biomed Mater 2016; 64:125-38. [DOI: 10.1016/j.jmbbm.2016.07.029] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 07/12/2016] [Accepted: 07/24/2016] [Indexed: 10/21/2022]
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Segarra MS, Shimada Y, Sadr A, Sumi Y, Tagami J. Three-Dimensional Analysis of Enamel Crack Behavior Using Optical Coherence Tomography. J Dent Res 2016; 96:308-314. [PMID: 27872333 DOI: 10.1177/0022034516680156] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The aim of this study was to nondestructively analyze enamel crack behavior on different areas of teeth using 3D swept source-optical coherence tomography (SS-OCT). Ten freshly extracted human teeth of each type on each arch ( n = 80 teeth) were inspected for enamel crack patterns on functional, contact and nonfunctional, or noncontact areas using 3D SS-OCT. The predominant crack pattern for each location on each specimen was noted and analyzed. The OCT observations were validated by direct observations of sectioned specimens under confocal laser scanning microscopy (CLSM). Cracks appeared as bright lines with SS-OCT, with 3 crack patterns identified: Type I - superficial horizontal cracks; Type II - vertically (occluso-gingival) oriented cracks; and Type III - hybrid or complicated cracks, a combination of a Type I and Type III cracks, which may or may not be confluent with each other. Type II cracks were predominant on noncontacting surfaces of incisors and canines and nonfunctional cusps of posterior teeth. Type I and III cracks were predominant on the contacting surfaces of incisors, cusps of canines, and functional cusps of posterior teeth. Cracks originating from the dental-enamel junction and enamel tufts, crack deflections, and the initiation of new cracks within the enamel (internal cracks) were observed as bright areas. CLSM observations corroborated the SS-OCT findings. We found that crack pattern, tooth type, and the location of the crack on the tooth exhibited a strong correlation. We show that the use of 3D SS-OCT permits for the nondestructive 3D imaging and analysis of enamel crack behavior in whole human teeth in vitro. 3D SS-OCT possesses potential for use in clinical studies for the analysis of enamel crack behavior.
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Affiliation(s)
- M S Segarra
- 1 Department of Cariology and Operative Dentistry, Tokyo Medical and Dental University, Japan.,2 Section of Operative Dentistry, College of Dentistry, University of the Philippines, Manila, Philippines
| | - Y Shimada
- 1 Department of Cariology and Operative Dentistry, Tokyo Medical and Dental University, Japan
| | - A Sadr
- 1 Department of Cariology and Operative Dentistry, Tokyo Medical and Dental University, Japan.,3 Restorative Dentistry, University of Washington, Seattle, WA, USA
| | - Y Sumi
- 4 Advanced Medicine, National Center for Geriatrics and Gerontology, Obu, Japan
| | - J Tagami
- 1 Department of Cariology and Operative Dentistry, Tokyo Medical and Dental University, Japan
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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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Abou Neel EA, Aljabo A, Strange A, Ibrahim S, Coathup M, Young AM, Bozec L, Mudera V. Demineralization-remineralization dynamics in teeth and bone. Int J Nanomedicine 2016; 11:4743-4763. [PMID: 27695330 PMCID: PMC5034904 DOI: 10.2147/ijn.s107624] [Citation(s) in RCA: 313] [Impact Index Per Article: 39.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Biomineralization is a dynamic, complex, lifelong process by which living organisms control precipitations of inorganic nanocrystals within organic matrices to form unique hybrid biological tissues, for example, enamel, dentin, cementum, and bone. Understanding the process of mineral deposition is important for the development of treatments for mineralization-related diseases and also for the innovation and development of scaffolds. This review provides a thorough overview of the up-to-date information on the theories describing the possible mechanisms and the factors implicated as agonists and antagonists of mineralization. Then, the role of calcium and phosphate ions in the maintenance of teeth and bone health is described. Throughout the life, teeth and bone are at risk of demineralization, with particular emphasis on teeth, due to their anatomical arrangement and location. Teeth are exposed to food, drink, and the microbiota of the mouth; therefore, they have developed a high resistance to localized demineralization that is unmatched by bone. The mechanisms by which demineralization-remineralization process occurs in both teeth and bone and the new therapies/technologies that reverse demineralization or boost remineralization are also scrupulously discussed. Technologies discussed include composites with nano- and micron-sized inorganic minerals that can mimic mechanical properties of the tooth and bone in addition to promoting more natural repair of surrounding tissues. Turning these new technologies to products and practices would improve health care worldwide.
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Affiliation(s)
- Ensanya Ali Abou Neel
- Division of Biomaterials, Operative Dentistry Department, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
- Biomaterials Department, Faculty of Dentistry, Tanta University, Tanta, Egypt
- Department of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London, UK
| | - Anas Aljabo
- Department of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London, UK
| | - Adam Strange
- Department of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London, UK
| | - Salwa Ibrahim
- Department of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London, UK
| | - Melanie Coathup
- UCL Institute of Orthopaedics and Musculoskeletal Sciences, Royal National Orthopaedic Hospital, Stanmore, London, UK
| | - Anne M Young
- Department of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London, UK
| | - Laurent Bozec
- Department of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London, UK
| | - Vivek Mudera
- UCL Institute of Orthopaedics and Musculoskeletal Sciences, Royal National Orthopaedic Hospital, Stanmore, London, UK
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Yahyazadehfar M, Zhang D, Arola D. On the importance of aging to the crack growth resistance of human enamel. Acta Biomater 2016; 32:264-274. [PMID: 26747980 DOI: 10.1016/j.actbio.2015.12.038] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 12/03/2015] [Accepted: 12/30/2015] [Indexed: 11/28/2022]
Abstract
With improvements in oral health and an overall increase in quality of life, the percentage of fully or largely dentate seniors is increasing. Understanding the effects of aging on the mechanical properties of teeth is essential to the maintenance of lifelong oral health. In this investigation the effects of aging on the fracture toughness of human enamel were evaluated from incremental crack growth experiments performed on tissue of donor teeth representing "young" (17 ⩽ age ⩽ 25) and "old" (age ⩾ 55) age groups. Results showed that the old enamel exhibited significantly lower resistance to fracture than that of the young tissue in two orthogonal directions of crack growth. For crack growth transverse to the enamel rods, the fracture toughness of the old enamel (0.37 ± 0.15 MPa m(0.5)) was nearly 70% lower than that of tissue from the young teeth (1.23 ± 0.20 MPa m(0.5)). Based on results from a mechanistic analysis of crack growth, the reduction in fracture resistance is attributed to a decrease in the degree of extrinsic toughening. The practice of restorative dentistry should account for these changes in tooth tissues in the treatment of senior patients. STATEMENT OF SIGNIFICANCE The mechanical behavior of enamel has been studied for over 3 decades. Due to the limited volume of tissue available for evaluation, past work has been largely based on indentation methods. In this investigation we have evaluated the resistance to fracture of human enamel using a conventional fracture mechanics approach and incremental crack growth. We compared the fracture resistance of cuspal enamel obtained from the teeth of representative "young" and "old" donor groups. Our results show that there is a substantial reduction in the resistance to fracture with age, that it is anisotropic, and that the degradation is more severe than that which occurs to dentin. As such, we feel this work is a significant contribution to the field.
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Affiliation(s)
- Mobin Yahyazadehfar
- Department of Material Science and Engineering, University of Washington, Seattle, WA, USA; Department of Mechanical Engineering, University of Maryland Baltimore County, Baltimore, MD, USA
| | - Dongsheng Zhang
- Department of Mechanics, Shanghai University, Shanghai 200444, PR China
| | - Dwayne Arola
- Department of Material Science and Engineering, University of Washington, Seattle, WA, USA; Department of Restorative Dentistry, School of Dentistry, University of Washington, Seattle, WA, USA; Department of Oral Health Sciences, School of Dentistry, University of Washington, Seattle, WA, USA.
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38
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Galo R, Contente MMMG, Galafassi D, Borsatto MC. Hardness and modulus of elasticity of primary and permanent teeth after wear against different dental materials. Eur J Dent 2016; 9:587-593. [PMID: 26929700 PMCID: PMC4745243 DOI: 10.4103/1305-7456.172635] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Objectives: The purpose of this study was to determine the Young's modulus and the hardness of deciduous and permanent teeth following wear challenges using different dental materials. Materials and Methods: Wear challenges were performed against four dental materials: A resin-based fissure sealant (Fluoroshield®), a glass ionomer based fissure sealant (Vitremer®), and two microhybrid composite resins (Filtek Z250 and P90®). Using the pin-on-plate design, a deciduous or a permanent tooth was made into a pin (4 mm × 4 mm × 2 mm) working at a 3 N vertical load, 1 Hz frequency, and 900 cycles (15 min) with Fusayama artificial saliva as a lubricant. Before and after the tribological tests, the hardness and elasticity modulus of the tooth samples were measured by creating a nanoindentation at load forces up to 50 mN and 150 mN. All of the results were statistically analyzed using ANOVA and post-hoc Duncan's tests (P < 0.05). Results: No difference in hardness was encountered between deciduous and permanent teeth (P < 0.05) or modulus of elasticity (P < 0.05) before or after the wear challenges for all of the dental materials tested. Conclusions: Wear challenges against the studied dental materials did not alter the properties of permanent or deciduous teeth after the application of a 3 N load.
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Affiliation(s)
- Rodrigo Galo
- Departament of Dentistry, Federal University of Valleys of Jequitinhonha and Mucuri, Diamantina, MG, 39100-000, Brasil
| | | | - Daniel Galafassi
- Department of Pediatric Clinics, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14040-904, Brazil
| | - Maria Cristina Borsatto
- Department of Pediatric Clinics, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14040-904, Brazil
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Lucas PW, Philip SM, Al-Qeoud D, Al-Draihim N, Saji S, van Casteren A. Structure and scale of the mechanics of mammalian dental enamel viewed from an evolutionary perspective. Evol Dev 2015; 18:54-61. [DOI: 10.1111/ede.12169] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Peter W. Lucas
- Department of Bioclinical Sciences; Faculty of Dentistry; Kuwait University; Jabriya, Kuwait, P.O. Box 24923 Safat 13110 Kuwait
| | - Swapna M. Philip
- Department of Bioclinical Sciences; Faculty of Dentistry; Kuwait University; Jabriya, Kuwait, P.O. Box 24923 Safat 13110 Kuwait
| | - Dareen Al-Qeoud
- Department of Bioclinical Sciences; Faculty of Dentistry; Kuwait University; Jabriya, Kuwait, P.O. Box 24923 Safat 13110 Kuwait
| | - Nuha Al-Draihim
- Department of Bioclinical Sciences; Faculty of Dentistry; Kuwait University; Jabriya, Kuwait, P.O. Box 24923 Safat 13110 Kuwait
| | - Sreeja Saji
- Department of Bioclinical Sciences; Faculty of Dentistry; Kuwait University; Jabriya, Kuwait, P.O. Box 24923 Safat 13110 Kuwait
| | - Adam van Casteren
- Max Planck Weizmann Center for Integrative Archaeology and Anthropology; Max Planck Institute for Evolutionary Anthropology; Deutscher Platz 6 D-04103 Leipzig Germany
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Hua L, Ungar P, Zhou Z, Ning Z, Zheng J, Qian L, Rose J, Yang D. Dental development and microstructure of bamboo rat incisors. BIOSURFACE AND BIOTRIBOLOGY 2015. [DOI: 10.1016/j.bsbt.2015.11.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Tolcachir BR, Crohare L, Gallará RV. Measuring color change of tooth enamel by in vitro remineralization of white spot lesion. JOURNAL OF ORAL RESEARCH 2015. [DOI: 10.17126/joralres.2015.072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Jia Y, Xuan FZ, Yang F. Viscoplastic response of tooth enamel under cyclic microindentation. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2015; 55:448-56. [PMID: 26117776 DOI: 10.1016/j.msec.2015.05.074] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 05/08/2015] [Accepted: 05/28/2015] [Indexed: 10/23/2022]
Abstract
Cyclic microindentations were performed on the occlusal surface and axial section of tooth enamel, using the Berkovich indenter. Under the action of a cyclic indentation load, the indenter continuously penetrated into the tooth enamel and reached a quasi-steady state at which the penetration depth per cycle was a constant. At the quasi-steady state, both the amplitude of the indentation depth and the penetration depth per cycle for the cyclic indentation of the axial section are larger than those for the indentation of the occlusal section under the same loading condition. The energy dissipation per cycle consists of two contributions; one is the plastic energy dissipated per cycle due to the propagation of the plastic zone underneath the indentation and the other is the energy dissipation due to the viscous flow during the cyclic indentation. Both the penetration depth and the plastic energy dissipated per cycle at the quasi-steady state are independent of the maximum applied load and increase with increasing the amplitude of the cyclic indentation load.
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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
| | - 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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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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Tostes MA, Santos E, Camargo SA. Effect of resin infiltration on the nanomechanical properties of demineralized bovine enamel. Indian J Dent 2015; 5:116-22. [PMID: 25565739 PMCID: PMC4213871 DOI: 10.4103/0975-962x.140819] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Objective: The aim of the present study was to evaluate the efficacy of resin infiltration in preventing in vitro lesion progression. Materials and Methods: Buccal surfaces of bovine incisors were divided into mesial and distal regions and, at the center, nail varnish was applied (1.0 mm width) to protect the enamel surface against any further treatment. In order to create artificial enamel lesions in the unprotected areas, each specimen was soaked in a demineralizing solution. After that, specimens had two enamel lesions. One lesion in each sample was etched with 15% HCl for 120 s and infiltrated with a commercial infiltrating resin for 3 min, while the other lesion was not treated (control). Each specimen was cross-sectionally halved and randomly allocated to two groups: Group 1 was immediately processed and Group 2 was submitted to a new demineralization process. The samples were analyzed by means of cross-sectional hardness measurements using a nanoindenter equipment. Hardness data were statistically analyzed by non-parametric Kruskal-Wallis and MannWhitney tests (α = 0.05). Results: The findings showed statistical difference between treatments at the same analyzed distance range from the outer surface of the enamel (P < 0.05). Conclusion: The untreated lesion showed lower hardness values for distances near the outer surface of the enamel. The resin infiltration was efficient in preventing further in vitro demineralization of bovine enamel lesions.
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Affiliation(s)
- Mônica Almeida Tostes
- Department of Pediatric Dentistry, School of Dentistry, Fluminense Federal University, Niterói, RJ, Brazil
| | - Emanuel Santos
- Department of Metallurgical and Materials Engineering, COPPE, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Sérgio Alvaro Camargo
- Department of Metallurgical and Materials Engineering, COPPE, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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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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Abstract
‘Bronze teeth' reflect the mechanical properties of natural teeth to a certain extent. Their mechanical properties resemble those of a tough metal, and the gradient of these properties lies in the direction from outside to inside. These attributes confer human teeth with effective mastication ability. Understanding the various mechanical properties of human teeth and dental materials is the basis for the development of restorative materials. In this study, the elastic properties, dynamic mechanical properties (visco-elasticity) and fracture mechanical properties of enamel and dentin were reviewed to provide a more thorough understanding of the mechanical properties of human teeth.
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Nogueira BC, Fernandes PM, Paiva AC, Fagundes NC, Teixeira FB, Lima RR. Avaliação comparativa da ultraestrutura e propriedades físicas do esmalte bovino, bubalino e humano. PESQUISA VETERINÁRIA BRASILEIRA 2014. [DOI: 10.1590/s0100-736x2014000500017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Este estudo teve como finalidade comparar a morfologia e propriedades físicas da estrutura do esmalte dos dentes bovinos, bubalinos e humanos. A análise deste tecido foi realizada por meio de microscopia eletrônica de varredura, composição mineral, microdureza e rugosidade superficial do esmalte em 41 incisivos bubalinos (Bos taurus indicus), 41 incisivos bovinos (Pelorovis antiques) e 30 incisivos permanentes de humanos. Os resultados mostraram que a ultraestrutura do esmalte revela uma significativa similaridade das espécies estudadas com a encontrada em amostras humanas. No esmalte bovino e bubalino os elementos químicos que apresentaram maior concentração foram: O, Ca e P, justamente os que formam os cristais de hidroxiapatita - Ca10(PO4)6(OH)2. Na microdureza Knoop não houve diferença estatisticamente significante entre as três espécies. Porém, a rugosidade superficial do esmalte bubalino (2,16µm ±0,23) foi significativamente maior quando comparada aos dentes humano (0,36µm ±0,05) e bovino (0,41µm ±0,07). Conclui-se que as características e propriedades do esmalte bovino e bubalino, por meio de análises e testes, apresentou uma morfologia semelhante à de humanos, arquitetura ultraestrutural similar, microdureza e composição mineral equivalente ao tecido dental humano, tornando-se modelos de referência para pesquisas.
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Dumont M, Tütken T, Kostka A, Duarte M, Borodin S. Structural and functional characterization of enamel pigmentation in shrews. J Struct Biol 2014; 186:38-48. [DOI: 10.1016/j.jsb.2014.02.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 02/06/2014] [Accepted: 02/11/2014] [Indexed: 10/25/2022]
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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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