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Nommeots-Nomm A, Houaoui A, Pradeepan Packiyanathar A, Chen X, Hokka M, Hill R, Pauthe E, Petit L, Boissière M, Massera J. Phosphate/oxyfluorophosphate glass crystallization and its impact on dissolution and cytotoxicity. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2020; 117:111269. [PMID: 32919633 DOI: 10.1016/j.msec.2020.111269] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 07/03/2020] [Accepted: 07/04/2020] [Indexed: 11/19/2022]
Abstract
The role of fluorine in bioactive glasses is of interest due to the potential of precipitating fluorapatite, a phase with higher chemical resistance than the typical hydroxyapatite precipitated from oxide bioactive glasses. However, the introduction of fluorine in silicate bioactive glasses was found deleterious to the bioactivity of the glass. Here, phosphate glasses with the composition 75NaPO3-(25-x) CaO-xCaF2 (in mol%), with x = 0-20 and glass-ceramics were investigated to evaluate their potential as substitutes to the traditional silicate bioactive glass. An increase in CaF2 substitution for CaO led to an increase in the glass solubility, due to an increase in highly soluble F(M)n species (where M is a cation) and to an increased polymerization of the phosphate network. Structural analysis reveals the formation of FP bonds, in addition to the F(M)n species, in the glass with the higher CaF2 content. Furthermore, with heat treatment, CaF2 crystals precipitate within the bulk in the newly developed glass, when x = 20. This bulk crystallization reduces the glass dissolution without compromising the precipitation of a reactive layer at the glass surface. Finally, in vitro cell tests were performed using MC3T3 pre-osteoblastic cells. While the substitution of CaF2 for CaO led to an increased cytotoxicity, the controlled crystallization of the fluorine containing glasses decreased such cytotoxicity to similar values than traditional bioactive phosphate glass (x0). This study reports on new oxyfluorophosphate glass and glass-ceramics able, not only, to precipitate a Ca-P reactive layer but also to be processed into glass-ceramics with controlled crystal size, density and cellular activity. STATEMENT OF SIGNIFICANCE: Uncontrolled crystallization of bioactive glasses has negative effect on the materials' bioactivity. While in silicate glass the bioactivity is solely reduced, in phosphate glasses it is often completely suppressed. Furthermore, the need for fluorine containing bioactive glasses, not only for use in bone reconstruction but also in toothpaste as emerged. The addition of F in both silicate and phosphate has led to challenges due the lack of Si-F or P-F bonds, generally leading to a decrease in bioactivity. Here, we developed a bioactive invert phosphate glass where up to 20 mol% of CaO was replaced with CaF2. In the new developed glasses, NMR demonstrated formation of P-F bonds. The content of fluorine was tailored to induce CaF2 bulk crystallization. Overall an increase in F was associated with an increase network connectivity. In turns it led to an increased dissolution rate which was linked to a higher cytotoxicity. Upon (partial to full) surface crystallization of the F-free glass, the bioactivity (ability to form a reactive layer) was loss and the cytotoxicity again increased due to the rapid dissolution of one crystal phase and of the remaining amorphous phase. On another hand, the controlled bulk precipitation of CaF2 crystals, in the F-containing glass, was associated with a reduced cytotoxicity. The new oxyfluorophosphate glass-ceramic developed is promising for application in the biomedical field.
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Affiliation(s)
- A Nommeots-Nomm
- Tampere University, Faculty of Medicine and Health Technology, Laboratory of Biomaterials and Tissue Engineering, Korkeakoulunkatu 3, 33720 Tampere, Finland
| | - A Houaoui
- Biomaterials for Health Research Group, ERRMECe, Equipe de recherche sur les Relations Matrice Extracellulaire-Cellules (EA1391), Institut des matériaux I-MAT (FD4122), CY Tech, CY Cergy Paris University, Maison Internationale de la Recherche (MIR), rue Descartes, 95001 Neuville sur Oise cedex, France
| | - A Pradeepan Packiyanathar
- Biomaterials for Health Research Group, ERRMECe, Equipe de recherche sur les Relations Matrice Extracellulaire-Cellules (EA1391), Institut des matériaux I-MAT (FD4122), CY Tech, CY Cergy Paris University, Maison Internationale de la Recherche (MIR), rue Descartes, 95001 Neuville sur Oise cedex, France
| | - X Chen
- Hunan Key Laboratory of Oral Health Research & Hunan 3D Printing Engineering Research Center of Oral Care Xiangya Stomatological Hospital & Xiangya School of Stomatology, Central South University, Changsha, 410008, Hunan, China
| | - M Hokka
- Tampere University of Technology, Laboratory of Material Sciences, Korkeakoulunkatu 3, 33720 Tampere, Finland
| | - R Hill
- Dental Physical Sciences, Institute of Dentistry, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - E Pauthe
- Biomaterials for Health Research Group, ERRMECe, Equipe de recherche sur les Relations Matrice Extracellulaire-Cellules (EA1391), Institut des matériaux I-MAT (FD4122), CY Tech, CY Cergy Paris University, Maison Internationale de la Recherche (MIR), rue Descartes, 95001 Neuville sur Oise cedex, France
| | - L Petit
- Tampere University of Technology, Laboratory of Photonics, Korkeakoulunkatu 3, 33720 Tampere, Finland
| | - M Boissière
- Biomaterials for Health Research Group, ERRMECe, Equipe de recherche sur les Relations Matrice Extracellulaire-Cellules (EA1391), Institut des matériaux I-MAT (FD4122), CY Tech, CY Cergy Paris University, Maison Internationale de la Recherche (MIR), rue Descartes, 95001 Neuville sur Oise cedex, France
| | - J Massera
- Tampere University, Faculty of Medicine and Health Technology, Laboratory of Biomaterials and Tissue Engineering, Korkeakoulunkatu 3, 33720 Tampere, Finland.
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Chen X, Karpukhina N, Brauer DS, Hill RG. High chloride content calcium silicate glasses. Phys Chem Chem Phys 2018; 19:7078-7085. [PMID: 28225127 DOI: 10.1039/c6cp07905a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Chloride is known to volatilize from silicate glass melts and until now, only a limited number of studies on oxychloride silicate glasses have been reported. In this paper we have synthesized silicate glasses that retain large amounts of CaCl2. The CaCl2 has been added to the calcium metasilicate composition (CaO·SiO2). Glasses were produced via a melt quench route and an average of 70% of the chloride was retained after melting. Up to 31.6 mol% CaCl2 has been successfully incorporated into these silicate glasses without the occurrence of crystallization. 29Si MAS-NMR spectra showed the silicon being present mainly as a Q2 silicate species. This suggests that chloride formed Cl-Ca(n) species, rather than Si-Cl bonds. Upon increasing the CaCl2 content, the Tg reduced markedly from 782 °C to 370 °C. Glass density and glass crystallization temperature decreased linearly with an increase in the CaCl2 content. However, both linear regressions revealed a breakpoint at a CaCl2 content just below 20 mol%. This might be attributed to a significant change in the structure and is also correlated with the nature of the crystallizing phases formed upon heat treatment. The glasses with less than 19.2 mol% CaCl2 crystallized to wollastonite, whilst the compositions with CaCl2 content equal to or greater than 19.2 mol% are thought to crystallize to CaCl2. In practice, the crystallization of CaCl2 could not occur until the crystallization temperature fell below the melting point of CaCl2. The implications of the results along with the high chloride retention are discussed.
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Affiliation(s)
- Xiaojing Chen
- Dental Physical Sciences, Institute of Dentistry, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Mile End Road, London E1 4NS, UK.
| | - Natalia Karpukhina
- Dental Physical Sciences, Institute of Dentistry, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Mile End Road, London E1 4NS, UK.
| | - Delia S Brauer
- Otto-Schott-Institut, Friedrich-Schiller-Universität, Fraunhoferstr. 6, Jena 07743, Germany
| | - Robert G Hill
- Dental Physical Sciences, Institute of Dentistry, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Mile End Road, London E1 4NS, UK.
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Montazerian M, Zanotto ED. Bioactive and inert dental glass-ceramics. J Biomed Mater Res A 2016; 105:619-639. [PMID: 27701809 DOI: 10.1002/jbm.a.35923] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 09/14/2016] [Accepted: 10/03/2016] [Indexed: 02/07/2023]
Abstract
The global market for dental materials is predicted to exceed 10 billion dollars by 2020. The main drivers for this growth are easing the workflow of dentists and increasing the comfort of patients. Therefore, remarkable research projects have been conducted and are currently underway to develop improved or new dental materials with enhanced properties or that can be processed using advanced technologies, such as CAD/CAM or 3D printing. Among these materials, zirconia, glass or polymer-infiltrated ceramics, and glass-ceramics (GCs) are of great importance. Dental glass-ceramics are highly attractive because they are easy to process and have outstanding esthetics, translucency, low thermal conductivity, high strength, chemical durability, biocompatibility, wear resistance, and hardness similar to that of natural teeth, and, in certain cases, these materials are bioactive. In this review article, we divide dental GCs into the following two groups: restorative and bioactive. Most restorative dental glass-ceramics (RDGCs) are inert and biocompatible and are used in the restoration and reconstruction of teeth. Bioactive dental glass-ceramics (BDGCs) display bone-bonding ability and stimulate positive biological reactions at the material/tissue interface. BDGCs are suggested for dentin hypersensitivity treatment, implant coating, bone regeneration and periodontal therapy. Throughout this paper, we elaborate on the history, processing, properties and applications of RDGCs and BDGCs. We also report on selected papers that address promising types of dental glass-ceramics. Finally, we include trends and guidance on relevant open issues and research possibilities. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 619-639, 2017.
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Affiliation(s)
- Maziar Montazerian
- Department of Materials Engineering (DEMa), Center for Research, Technology and Education in Vitreous Materials (CeRTEV), Federal University of São Carlos (UFSCar), São Carlos, SP, 13.565-905, Brazil
| | - Edgar Dutra Zanotto
- Department of Materials Engineering (DEMa), Center for Research, Technology and Education in Vitreous Materials (CeRTEV), Federal University of São Carlos (UFSCar), São Carlos, SP, 13.565-905, Brazil
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Fathi HM, Miller C, Stokes C, Johnson A. The effect of ZrO2 and TiO 2 on solubility and strength of apatite-mullite glass-ceramics for dental applications. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2014; 25:583-594. [PMID: 24249630 DOI: 10.1007/s10856-013-5096-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 11/11/2013] [Indexed: 06/02/2023]
Abstract
The effect of ZrO2 and TiO2 on the chemical and mechanical properties of apatite-mullite glass-ceramics was investigated after sample preparation according to the ISO (2768:2008) recommendations for dental ceramics. All materials were characterized using differential thermal analysis, X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. X-ray fluorescence spectroscopy was used to determine the concentrations of elements present in all materials produced. The chemical solubility test and the biaxial flexural strength (BFS) test were then carried out on all the samples. The best solubility value of 242 ± 61 μg/cm(2) was obtained when HG1T was heat-treated for 1 h at the glass transition temperature plus 20 °C (Tg + 20 °C) followed by 5 h at 1200 °C. The highest BFS value of 174 ± 38 MPa was achieved when HG1Z and HG1Z+T were heat-treated for 1 h at the Tg + 20 °C followed by 7 h at 1200 °C. The present study has demonstrated that the addition of TiO2 to the reference composition showed promise in both the glass and heat-treated samples. However, ZrO2 is an effective agent for developing the solubility or the mechanical properties of an apatite-mullite glass-ceramic separately but does not improve the solubility and the BFS simultaneously.
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Affiliation(s)
- Hawa M Fathi
- Academic Unit of Restorative Dentistry, School of Clinical Dentistry, University of Sheffield, Claremont Crescent, Sheffield, S10 2TA, UK,
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Abstract
BACKGROUND There are many different ceramic systems available on the market for dental restorations. Glass-ceramics are a popular choice due to their excellent esthetics and ability to bond to tooth structure allowing a more conservative approach. However, at present, these materials have insufficient strength to be used reliably in posterior regions of the mouth. PURPOSE The aim of this review article is to discuss the types of novel glass-ceramic currently be investigated including composition, microstructure and properties. CONCLUSION Current research in glass-ceramics focuses on the quest for a highly esthetic material along with sufficient strength to enable crowns and bridgework to be reliably placed in these areas. CLINICAL SIGNIFICANCE There is a gap in the market for a machinable resin bonded glass-ceramic with sufficient strength as well as excellent esthetics.
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Affiliation(s)
- Sarah Pollington
- Academic Unit of Restorative Dentistry, School of Clinical Dentistry, Claremont Crescent, Sheffield S10 2TA, UK.
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Lee SH, Kim HE, Kim HW. Improvement in crystallinity of apatite coating on titanium with the insertion of CaF2 buffer layer. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2008; 19:1905-11. [PMID: 17914616 DOI: 10.1007/s10856-007-3260-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2006] [Accepted: 07/09/2007] [Indexed: 05/17/2023]
Abstract
In the apatite coatings on Ti the heat treatment process is necessary to crystallize the apatite structure for improved chemical stability and biological properties. However, the heat treatment normally degrades the mechanical strength of the coating layer associated with thermally induced stress. In this study, we aimed to improve the crystallization of apatite coating by using calcium fluoride (CaF2) as a buffer layer. The insertion of a thin layer of CaF2 (0.2-1 microm) between apatite and Ti significantly improved the crystallization behavior of apatite. Moreover, this crystallization was more enhanced as the thickness of CaF2 was increased. When a 1 microm-thick CaF2 was inserted, the crystallization of apatite initiated at a temperature as low as 320 degrees C, being a dramatic improvement in the crystallization when considering the crystallization initiation temperature of a bare apatite coating on Ti was approximately 450 degrees C. As a result of this crystallization enhancement, the dissolution behavior of CaF2-inserted apatite coatings was more stable than that of the bare apatite coating, showing much reduced initial-burst effect. Preliminary cellular assay showed the CaF2-inserted apatite coating provided a substrate for cells to spread and grow favorably, as being similar to the bare apatite coating. This novel way of apatite coating on Ti using CaF2 buffer layer may be useful in the coating systems particularly requiring low temperature processing and increased crystallinity with high chemical stability.
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Affiliation(s)
- Su-Hee Lee
- School of Materials Science and Engineering, Seoul National University, Seoul, 151-744, Korea
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