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Räägel H, Turley A, Fish T, Franson J, Rollins T, Campbell S, Jorgensen MR. Medical Device Industry Approaches for Addressing Sources of Failing Cytotoxicity Scores. Biomed Instrum Technol 2021. [PMID: 34043008 DOI: 10.2345/0890-8205-55.2.69] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
To ensure patient safety, medical device manufacturers are required by the Food and Drug Administration and other regulatory bodies to perform biocompatibility evaluations on their devices per standards, such as the AAMI-approved ISO 10993-1:2018 (ANSI/AAMI/ISO 10993-1:2018).However, some of these biological tests (e.g., systemic toxicity studies) have long lead times and are costly, which may hinder the release of new medical devices. In recent years, an alternative method using a risk-based approach for evaluating the toxicity (or biocompatibility) profile of chemicals and materials used in medical devices has become more mainstream. This approach is used as a complement to or substitute for traditional testing methods (e.g., systemic toxicity endpoints). Regardless of the approach, the one test still used routinely in initial screening is the cytotoxicity test, which is based on an in vitro cell culture system to evaluate potential biocompatibility effects of the final finished form of a medical device. However, it is known that this sensitive test is not always compatible with specific materials and can lead to failing cytotoxicity scores and an incorrect assumption of potential biological or toxicological adverse effects. This article discusses the common culprits of in vitro cytotoxicity failures, as well as describes the regulatory-approved methodology for cytotoxicity testing and the approach of using toxicological risk assessment to address clinical relevance of cytotoxicity failures for medical devices. Further, discrepancies among test results from in vitro tests, use of published half-maximal inhibitory concentration data, and the derivation of their relationship to tolerable exposure limits, reference doses, or no observed adverse effect levels are highlighted to demonstrate that although cytotoxicity tests in general are regarded as a useful sensitive screening assays, specific medical device materials are not compatible with these cellular/in vitro systems. For these cases, the results should be analyzed using more clinically relevant approaches (e.g., through chemical analysis or written risk assessment).
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Räägel H, Turley A, Fish T, Franson J, Rollins T, Campbell S, Jorgensen MR. Medical Device Industry Approaches for Addressing Sources of Failing Cytotoxicity Scores. Biomed Instrum Technol 2021; 55:69-84. [PMID: 34043008 PMCID: PMC8641414 DOI: 10.2345/0899-8205-55.2.69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
To ensure patient safety, medical device manufacturers are required by the Food and Drug Administration and other regulatory bodies to perform biocompatibility evaluations on their devices per standards, such as the AAMI-approved ISO 10993-1:2018 (ANSI/AAMI/ISO 10993-1:2018).However, some of these biological tests (e.g., systemic toxicity studies) have long lead times and are costly, which may hinder the release of new medical devices. In recent years, an alternative method using a risk-based approach for evaluating the toxicity (or biocompatibility) profile of chemicals and materials used in medical devices has become more mainstream. This approach is used as a complement to or substitute for traditional testing methods (e.g., systemic toxicity endpoints). Regardless of the approach, the one test still used routinely in initial screening is the cytotoxicity test, which is based on an in vitro cell culture system to evaluate potential biocompatibility effects of the final finished form of a medical device. However, it is known that this sensitive test is not always compatible with specific materials and can lead to failing cytotoxicity scores and an incorrect assumption of potential biological or toxicological adverse effects. This article discusses the common culprits of in vitro cytotoxicity failures, as well as describes the regulatory-approved methodology for cytotoxicity testing and the approach of using toxicological risk assessment to address clinical relevance of cytotoxicity failures for medical devices. Further, discrepancies among test results from in vitro tests, use of published half-maximal inhibitory concentration data, and the derivation of their relationship to tolerable exposure limits, reference doses, or no observed adverse effect levels are highlighted to demonstrate that although cytotoxicity tests in general are regarded as a useful sensitive screening assays, specific medical device materials are not compatible with these cellular/in vitro systems. For these cases, the results should be analyzed using more clinically relevant approaches (e.g., through chemical analysis or written risk assessment).
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Affiliation(s)
- Helin Räägel
- Helin Räägel, PhD, is a senior biocompatibility expert at Nelson Laboratories in Salt Lake City, UT.
| | - Audrey Turley
- Audrey Turley, BS, is a senior biocompatibility expert at Nelson Laboratories in Salt Lake City, UT.
| | - Trevor Fish
- Trevor Fish, MS, is a toxicologist at Nelson Laboratories in Salt Lake City, UT.
| | - Jeralyn Franson
- Jeralyn Franson, MS, is an associate technical consultant at Nelson Laboratories in Salt Lake City, UT.
| | - Thor Rollins
- Thor Rollins, BS, is a director of toxicology and E&L consulting at Nelson Laboratories in Salt Lake City, UT.
| | - Sarah Campbell
- Sarah Campbell, PhD, DABT, is a principal toxicologist at Nelson Laboratories in Salt Lake City, UT, and a title in the College of Pharmacy at the University of Utah, in Salt Lake City, UT.
| | - Matthew R. Jorgensen
- Matthew R Jorgensen, PhD, DABT, is a chemist, materials scientist, and toxicologist at Nelson Laboratories in Salt Lake City, UT.
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Fatigue behaviour of dental crowns made from a novel high-performance polymer PEKK. Clin Oral Investig 2021; 25:4895-4905. [PMID: 33506428 PMCID: PMC8342378 DOI: 10.1007/s00784-021-03797-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 01/13/2021] [Indexed: 11/11/2022]
Abstract
Objectives The aim of this study was, firstly, to analyse the long-time fatigue behaviour of crowns constructed from a novel polyetherketoneketone (PEKK) polymer, using artificial prepared teeth. Secondly, to determine the effect of the material’s stiffness that used as an artificial prepared tooth on the fatigue life of the PEKK crowns in comparison to human prepared teeth. Methods Veneered crowns with a PEKK framework were constructed on three different prepared teeth: artificial polymethyl methacrylate (PMMA) teeth, artificial CoCr teeth and extracted human teeth. As far as applicable, the loading protocol was based on EN ISO 14801:2007 for fatigue testing of dental implants. After initial static fracture tests on three specimens from each group, the remaining crowns were loaded with different force levels until fracture or until 2 × 106 loading cycles were reached. The number of loading cycles until failure was recorded. Wöhler curves were created to display the fatigue limits. Results Static fracture limits as well as fatigue limits differed for all three core materials. The static fracture tests resulted in fracture limits of 1200 (± 293) N for the PMMA group, 1330 (± 219) N for the CoCr group and 899 (± 96) N for the human tooth group. Fatigue limits of 770 N, 840 N and 720 N were determined for the PMMA group, CoCr group and human tooth group, respectively. Conclusions The determined fatigue limit of above 720 N (depending on the core material) is sufficiently high and a good performance of this crown material is expected in the clinical loading life. The results showed that using artificial teeth instead of natural teeth for fatigue testing of crowns might result in an overestimation of the fatigue limits of the crown material. Clinical relevance PEKK-made crowns offer a stable and priceworthy treatment for patients, in particular those that suffer from metal allergy.
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Vasylevskyi S, Holzheu A, Fromm KM. Solid-state structure and antimicrobial and cytotoxicity studies of a cucurbit[6]uril-like Cu 6L 4 constructed from 3,5-bis[(1H-tetrazol-5-yl)methyl]-4H-1,2,4-triazol-4-amine. ACTA CRYSTALLOGRAPHICA SECTION C-STRUCTURAL CHEMISTRY 2018; 74:1413-1419. [PMID: 30398196 DOI: 10.1107/s2053229618013670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 09/25/2018] [Indexed: 11/10/2022]
Abstract
3,5-Bis[(1H-tetrazol-5-yl)methyl]-4H-1,2,4-triazol-4-amine (H2L) associates under deprotonation with CuSO4 in aqueous medium to form a new waisted barrel-shaped M6L4 cluster, namely hexaaquatetrakis{μ4-3,5-bis[(1H-tetrazol-5-yl)methyl]-4H-1,2,4-triazol-4-amine}-μ4-sulfato-hexacopper(II) sulfate hydrate, [Cu6(SO4)(C6H6N12)4(H2O)6]SO4·nH2O (n = ∼23) (1). Cluster 1 resembles concave cucurbit[6]uril and has one disordered sulfate anion trapped inside the cage, which additionally stabilizes the Cu6 unit. The CuII ions have either a square-pyramidal or a distorted octahedral geometry. The equatorial positions are filled by N atoms from the L2- ligand, while the axial positions are occupied by coordinated water molecules and O atoms of the sulfate counter-ion. In the solid state, the Cu6 clusters are connected through a large number of hydrogen bonds formed by uncoordinated water molecules and an additional sulfate anion. The compound shows good antimicrobial activity against E. coli tested with the Kirby Bauer approach. In addition, the cell viability towards HeLa and L-929 cells was studied.
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Affiliation(s)
- Serhii Vasylevskyi
- Chemistry Department, University of Fribourg, Chemin du Musée 9, Fribourg, CH-1700, Switzerland
| | - Anja Holzheu
- Chemistry Department, University of Fribourg, Chemin du Musée 9, Fribourg, CH-1700, Switzerland
| | - Katharina M Fromm
- Chemistry Department, University of Fribourg, Chemin du Musée 9, Fribourg, CH-1700, Switzerland
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Zhao YY, Chu Q, Shi XE, Zheng XD, Shen XT, Zhang YZ. Toxicity testing of four silver nanoparticle-coated dental castings in 3-D LO2 cell cultures. J Zhejiang Univ Sci B 2018; 19:159-167. [PMID: 29405043 DOI: 10.1631/jzus.b1600482] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
To address the controversial issue of the toxicity of dental alloys and silver nanoparticles in medical applications, an in vivo-like LO2 3-D model was constructed within polyvinylidene fluoride hollow fiber materials to mimic the microenvironment of liver tissue. The use of microscopy methods and the measurement of liver-specific functions optimized the model for best cell performances and also proved the superiority of the 3-D LO2 model when compared with the traditional monolayer model. Toxicity tests were conducted using the newly constructed model, finding that four dental castings coated with silver nanoparticles were toxic to human hepatocytes after cell viability assays. In general, the toxicity of both the castings and the coated silver nanoparticles aggravated as time increased, yet the nanoparticles attenuated the general toxicity by preventing metal ion release, especially at high concentrations.
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Affiliation(s)
- Yi-Ying Zhao
- Department of Food Science and Nutrition, Zhejiang Key Laboratory for Agro-Food Processing, Fuli Institute of Food Science, Hangzhou 310058, China
| | - Qiang Chu
- Department of Food Science and Nutrition, Zhejiang Key Laboratory for Agro-Food Processing, Fuli Institute of Food Science, Hangzhou 310058, China
| | - Xu-Er Shi
- Department of Food Science and Nutrition, Zhejiang Key Laboratory for Agro-Food Processing, Fuli Institute of Food Science, Hangzhou 310058, China
| | - Xiao-Dong Zheng
- Department of Food Science and Nutrition, Zhejiang Key Laboratory for Agro-Food Processing, Fuli Institute of Food Science, Hangzhou 310058, China
| | - Xiao-Ting Shen
- Huajiachi Dental Center, Stomatology Hospital Affiliated to Zhejiang University of Medicine, Hangzhou 310006, China
| | - Yan-Zhen Zhang
- Department of General Dentistry, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310012, China
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Gollwitzer H, Haenle M, Mittelmeier W, Heidenau F, Harrasser N. A biocompatible sol-gel derived titania coating for medical implants with antibacterial modification by copper integration. AMB Express 2018; 8:24. [PMID: 29460231 PMCID: PMC5818389 DOI: 10.1186/s13568-018-0554-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 06/01/2017] [Indexed: 12/19/2022] Open
Abstract
Implant-associated infections are dangerous complications and may cause dramatic illness with hematogeneous spread of bacteria and secondary infections. Since treatment of these infections remains most challenging and commonly requires implant removal, prevention is of utmost importance. In the present work a titania-sol was equipped with a copper salt resulting after calcination in a titania coating (TiO2) with antibacterial properties combined with good cytocompatibility. In vitro tests with bacteria as well as tissue cells were carried out under corresponding conditions. Mouse fibroblasts and different staphylococcal strains were used for growth inhibition assays with serial dilutions of CuCl2. Cultivation on the surface of bare Ti6Al4V, TiO2-coated and copper-filled TiO2-coated Ti6Al4V samples was performed with both bacteria and tissue cells. Bacterial and cellular proliferation and mitochondrial activity were hereby determined. Coating of Ti6Al4V with pure TiO2 significantly improved cytocompatibility compared to the uncoated alloy. In the growth inhibition assays, fibroblasts tolerated higher concentrations of copper ions than did bacteria. Nevertheless, copper integration reduced fibroblast proliferation and mitochondrial activity on the surface coating. On the other hand, integration of copper into the TiO2-coating significantly reduced adhesion of viable bacteria resulting in a promising combination of cytocompatibility and antibacterial properties. Additionally, significant bacterial growth inhibition by antibacterial amounts of copper was also demonstrated in the supernatant. In conclusion, the copper-loaded TiO2-coatings for medical implants may be a promising approach to reduce the rate of implant-associated infections.
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Affiliation(s)
- Hans Gollwitzer
- Clinic of Orthopedics and Sports Orthopedics, Technische Universität München, Ismaninger Str. 22, 81675 Munich, Germany
- ATOS Klinik München, Effnerstr. 38, 81925 Munich, Germany
| | - Maximilian Haenle
- Klinik für Sportorthopädie und arthroskopische Chirurgie, Orthopädische Fachkliniken der Hessing-Stiftung, Hessingstr. 17, 86199 Augsburg, Germany
| | - Wolfram Mittelmeier
- Department for Orthopaedic Surgery, University Medicine Rostock, Doberaner Str. 142, 18057 Rostock, Germany
| | - Frank Heidenau
- BioCer Entwicklungs GmbH, Birkenstr. 14, 95488 Eckersdorf, Germany
| | - Norbert Harrasser
- Clinic of Orthopedics and Sports Orthopedics, Technische Universität München, Ismaninger Str. 22, 81675 Munich, Germany
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Guttal SS, Nadiger RK, Shetty P. Cytotoxic effect of indigenously fabricated dental magnets for application in prosthodontics. J Indian Prosthodont Soc 2018; 18:29-34. [PMID: 29430139 PMCID: PMC5799965 DOI: 10.4103/jips.jips_114_17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 10/20/2017] [Indexed: 11/04/2022] Open
Abstract
Context Dental magnets are used for retaining removable prostheses such as a removable partial denture, complete denture, and maxillofacial prosthesis. They provide good retention for the prostheses. However, the elements released from the magnets may be cytotoxic for the tissues. Therefore, it is necessary to evaluate their cytotoxic effect on cell lines. Aim The aim of the study is to check the cytotoxic effect of indigenously fabricated dental magnets on animal cell lines. Materials and Methods Neodymium-iron-boron (Nd-Fe-B) magnet was tested for cytotoxicity. The magnet was encased in a teflon cylinder. Magnets were placed in the well tissue-cultured plates together with a suspension containing NIH 3T3 mouse fibroblasts (5 × 105 cells/ml). After 3 days of incubation at 37°C, cell viability was determined by mean transit time (MTT) assay. Cells were subsequently dissolved in 100 μl dimethyl sulfoxide with gentle shaking for 2 h at room temperature followed by measurement of absorbance at 570 nm. Eight replicate wells were used at each point in each of four separate measurements. Measured absorbance values were directly used for calculating percent of viable cells remaining after the respective treatment. Data were analyzed statistically with significance level set at P < 0.05. Results The control group had highest absorbance reading for the MTT assay followed by test group. The lowest values were found with bare Nd-Fe-B magnets. One-way ANOVA test was performed for the data obtained. There was a statistical significant difference seen in the positive control (bare magnets, 44.96) and the test (teflon cased magnets, 96.90) group. Conclusion More number of viable cells was visible in test group cells indicating that the indigenously fabricated dental magnet did not show any cytotoxicity.
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Affiliation(s)
| | - Ramesh K Nadiger
- Department of Prosthodontics, SDM College of Dental Sciences and Hospital, Dharwad, Karnataka, India
| | - Pravinkumar Shetty
- Department of Biochemistry, Central Research Lab, SDM College of Medical Sciences and Hospital, Dharwad, Karnataka, India
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Schmalz G, Galler KM. Biocompatibility of biomaterials – Lessons learned and considerations for the design of novel materials. Dent Mater 2017; 33:382-393. [DOI: 10.1016/j.dental.2017.01.011] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 01/31/2017] [Indexed: 12/14/2022]
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Nierlich J, Papageorgiou SN, Bourauel C, Hültenschmidt R, Bayer S, Stark H, Keilig L. Corrosion behavior of dental alloys used for retention elements in prosthodontics. Eur J Oral Sci 2016; 124:287-94. [PMID: 27061513 DOI: 10.1111/eos.12267] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/12/2016] [Indexed: 11/29/2022]
Abstract
The purpose of this study was to investigate the corrosion behavior of 10 different high noble gold-based dental alloys, used for prosthodontic retention elements, according to ISO 10271. Samples of 10 high-noble and noble gold-based dental alloys were subjected to: (i) static immersion tests with subsequent analysis of ion release for eight different elements using mass spectrometry; (ii) electrochemical tests, including open-circuit potential and potentiodynamic scans; and (iii) scanning electron microscopy, followed by energy-dispersive X-ray microscopy. The results were analyzed using one-way ANOVA and Sidak multiple-comparisons post-hoc test at a level of significance of α = 0.05. Significant differences were found among the 10 alloys studied for all ions (P < 0.001). The potentiodynamic analysis showed values from -82.5 to 102.8 mV for the open-circuit potential and from 566.7 to 1367.5 mV for the breakdown potential. Both the open-circuit and the breakdown potential varied considerably among these alloys. Scanning electron microscopy analysis confirmed the existence of typically small-diameter corrosion defects, whilst the energy-dispersive X-ray analysis found no significant alteration in the elemental composition of the alloys. The results of this study reveal the variability in the corrosive resistance among the materials used for retention elements in prosthodontics.
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Affiliation(s)
- Judith Nierlich
- Department of Oral Technology, School of Dentistry, University of Bonn, Bonn, Germany
| | - Spyridon N Papageorgiou
- Department of Oral Technology, School of Dentistry, University of Bonn, Bonn, Germany.,Department of Orthodontics, School of Dentistry, University of Bonn, Bonn, Germany
| | - Christoph Bourauel
- Department of Oral Technology, School of Dentistry, University of Bonn, Bonn, Germany
| | - Robert Hültenschmidt
- Department of Prosthetic Dentistry, Preclinical Education and Materials Science, School of Dentistry, University of Bonn, Bonn, Germany
| | - Stefan Bayer
- Department of Prosthetic Dentistry, Preclinical Education and Materials Science, School of Dentistry, University of Bonn, Bonn, Germany
| | - Helmut Stark
- Department of Prosthetic Dentistry, Preclinical Education and Materials Science, School of Dentistry, University of Bonn, Bonn, Germany
| | - Ludger Keilig
- Department of Oral Technology, School of Dentistry, University of Bonn, Bonn, Germany.,Department of Prosthetic Dentistry, Preclinical Education and Materials Science, School of Dentistry, University of Bonn, Bonn, Germany
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Grillo CA, Alvarez F, Fernández Lorenzo de Mele MA. Degradation of bioabsorbable Mg-based alloys: Assessment of the effects of insoluble corrosion products and joint effects of alloying components on mammalian cells. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2016; 58:372-80. [DOI: 10.1016/j.msec.2015.08.043] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 07/16/2015] [Accepted: 08/22/2015] [Indexed: 02/06/2023]
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Holm C, Morisbak E, Kalfoss T, Dahl JE. In vitro element release and biological aspects of base-metal alloys for metal-ceramic applications. ACTA BIOMATERIALIA ODONTOLOGICA SCANDINAVICA 2015. [PMID: 28642904 PMCID: PMC5433186 DOI: 10.3109/23337931.2015.1069714] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Objective: The aims of this study were to investigate the release of element from, and the biological response in vitro to, cobalt–chromium alloys and other base–metal alloys used for the fabrication of metal-ceramic restorations. Material and methods: Eighteen different alloys were investigated. Nine cobalt–chromium alloys, three nickel–chromium alloys, two cobalt–chromium–iron alloys, one palladium–silver alloy, one high-noble gold alloy, titanium grade II and one type III copper–aluminium alloy. Pure copper served as positive control. The specimens were prepared according to the ISO standards for biological and corrosion testing. Passive leaching of elements was measured by using Inductively Coupled Plasma – Mass Spectrometry (ICP-MS) after incubation in cell culture media, MEM, for 3 days. Corrosion testing was carried out in 0.9% sodium chloride (NaCl) and 1% lactic acid for 7 days, and the element release was measured by Inductively Coupled Plasma – Optical Emission Spectroscopy (ICP-OES). The biological response from the extract solutions was measured though MTT cytotoxicity testing and the Hen's egg test-chorio-allantoic membrane (HET-CAM) technique for irritationt. Results: The corrosion test showed similar element release from base-metal alloys compared to noble alloys such as gold. Apart from the high-copper alloy, all alloys expressed low element release in the immersion test, no cytotoxic effect in the MTT test, and were rated non-irritant in the HET-CAM test. Conclusions: Minimal biological response was observed for all the alloys tested, with the exception of the high-copper alloy.
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Affiliation(s)
- Charlotta Holm
- NIOM, Nordic Institute of Dental MaterialsOsloNorway.,The Swedish National Dental Health ServiceLuleåSweden
| | - Else Morisbak
- NIOM, Nordic Institute of Dental MaterialsOsloNorway
| | - Torill Kalfoss
- Environmental Chemistry, Norwegian University of Life SciencesOsloNorway
| | - Jon E Dahl
- NIOM, Nordic Institute of Dental MaterialsOsloNorway
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Milheiro A, Nozaki K, Kleverlaan CJ, Muris J, Miura H, Feilzer AJ. In vitro cytotoxicity of metallic ions released from dental alloys. Odontology 2014; 104:136-42. [PMID: 25549610 DOI: 10.1007/s10266-014-0192-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 12/15/2014] [Indexed: 10/24/2022]
Abstract
The cytotoxicity of a dental alloy depends on, but is not limited to, the extent of its corrosion behavior. Individual ions may have effects on cell viability that are different from metals interacting within the alloy structure. We aimed to investigate the cytotoxicity of individual metal ions in concentrations similar to those reported to be released from Pd-based dental alloys on mouse fibroblast cells. Metal salts were used to prepare seven solutions (concentration range 100 ppm-1 ppb) of the transition metals, such as Ni(II), Pd(II), Cu(II), and Ag(I), and the metals, such as Ga(III), In(III), and Sn(II). Cytotoxicity on mouse fibroblasts L929 was evaluated using the MTT assay. Ni, Cu, and Ag are cytotoxic at 10 ppm, Pd and Ga at 100 ppm. Sn and In were not able to induce cytotoxicity at the tested concentrations. Transition metals were able to induce cytotoxic effects in concentrations similar to those reported to be released from Pd-based dental alloys. Ni, Cu, and Ag were the most cytotoxic followed by Pd and Ga; Sn and In were not cytotoxic. Cytotoxic reactions might be considered in the etiopathogenesis of clinically observed local adverse reactions.
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Affiliation(s)
- Ana Milheiro
- Department of Dental Materials Science, ACTA, University of Amsterdam and VU University, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands.
| | - Kosuke Nozaki
- Department of Material Biofunctions, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo, 101-0062, Japan
| | - Cornelis J Kleverlaan
- Department of Dental Materials Science, ACTA, University of Amsterdam and VU University, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| | - Joris Muris
- Department of Dental Materials Science, ACTA, University of Amsterdam and VU University, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| | - Hiroyuki Miura
- Department of Fixed Prosthodontics, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Albert J Feilzer
- Department of Dental Materials Science, ACTA, University of Amsterdam and VU University, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
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Real-time cell analysis of the cytotoxicity of orthodontic brackets on gingival fibroblasts. J Appl Biomater Funct Mater 2014; 12:248-55. [PMID: 24425375 DOI: 10.5301/jabfm.5000165] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/27/2012] [Indexed: 11/20/2022] Open
Abstract
PURPOSE The aim of this study was to evaluate the cytotoxic effects of 6 different orthodontic bracket types on human gingival fibroblasts (HGFs) using the xCELLigence system.
METHODS The orthodontic brackets used in this study were gold-plated steel (Apollo Gold), titanium (Rematitan), stainless steel (Equilibrium 2), lucid ice (Inspire ICE), metal-reinforced ceramic (Clarity) and composite (OrthoFlex). Gingival fibroblasts were isolated from human gingival connective tissue of systemically healthy individuals. Tested brackets were incubated in DMEM culture medium for 72 hours according to ISO 10993-5 standards. Gingival fibroblasts were maintained with Dulbecco modified Eagle medium containing 10% fetal bovine serum. The xCELLigence system was used to evaluate cell survival. The statistical analysis used was ANOVA and Tukey-Kramer multiple comparison tests.
RESULTS When the data were evaluated in the 30th hour, Apollo Gold showed significant decreases in cell index (P<0.001). It also showed statistically significant decreases (P<0.001) in the 65th hour, but Clarity and Inspire ICE showed significant increases in cell indices (P<0.001, P<0.01). In the 114th hour, Clarity and Equilibrium 2 showed statistically significant increases in cell indices (P<0.001). Inspire ICE and Rematitan demonstrated significant increases (P<0.05). There were significant decreases in cell index of Apollo Gold (P<0.001).
CONCLUSIONS The tested brackets are suitable for clinical application, but further studies using different test methods are needed for gold-plated brackets.
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Elshahawy W, Watanabe I. Biocompatibility of dental alloys used in dental fixed prosthodontics. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.tdj.2014.07.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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15
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Cellular response to rare earth mixtures (La and Gd) as components of degradable Mg alloys for medical applications. Colloids Surf B Biointerfaces 2014; 117:312-21. [DOI: 10.1016/j.colsurfb.2014.02.030] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 02/18/2014] [Accepted: 02/19/2014] [Indexed: 01/18/2023]
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Martín-Cameán A, Jos A, Calleja A, Gil F, Iglesias A, Solano E, Cameán AM. Validation of a method to quantify titanium, vanadium and zirconium in oral mucosa cells by inductively coupled plasma-mass spectrometry (ICP-MS). Talanta 2014; 118:238-44. [DOI: 10.1016/j.talanta.2013.10.035] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 10/07/2013] [Accepted: 10/15/2013] [Indexed: 11/28/2022]
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Ristic L, Vucevic D, Radovic L, Djordjevic S, Nikacevic M, Colic M. Corrosive and cytotoxic properties of compact specimens and microparticles of Ni-Cr dental alloy. J Prosthodont 2013; 23:221-6. [PMID: 24118161 DOI: 10.1111/jopr.12100] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/23/2013] [Indexed: 11/27/2022] Open
Abstract
PURPOSE Nickel-chromium (Ni-Cr) dental alloys have been widely used in prosthodontic practice, but there is a permanent concern about their biocompatibility due to the release of metal ions. This is especially important when Ni-Cr metal microparticles are incorporated into gingival tissue during prosthodontic procedures. Therefore, the aim of this study was to examine and compare the corrosion and cytotoxic properties of compact specimens and microparticles of Ni-Cr dental alloy. MATERIALS AND METHODS Ni-Cr alloy, Remanium CSe bars (4 mm diameter), were made by the standard casting method and then cut into 0.5-mm-thick disks. Metal particles were obtained by scraping the bars using a diamond instrument for crown preparation. The microstructure was observed by an optical microscope. Quantitative determination and morphological and dimensional characterization of metal particles were carried out by a scanning electron microscope and Leica Application Suite software for image analysis. Corrosion was studied by conditioning the alloy specimens in the RPMI 1640 medium, containing 10% fetal calf serum in an incubator with 5% CO2 for 72 hours at 37°C. Inductively coupled plasma-optical emission spectrometry was used to assess metal ion release. The cytotoxity of conditioning medium (CM) was investigated on L929 cells using an MTT test. One-way ANOVA was used for statistical analysis. RESULTS After casting, the microstructure of the Remanium CSe compact specimen composed of Ni, Cr, Mo, Si, Fe, Al, and Co had a typical dendritic structure. Alloy microparticles had an irregular shape with a wide size range: from less than 1 μm to more than 100 μm. The release of metal ions, especially Ni and Mo from microparticles, was significantly higher, compared to the compact alloy specimen. The CM prepared from compact alloy was not cytotoxic at any tested dilutions, whereas CM from alloy microparticles showed dose-dependent cytotoxicity (90% CM and 45% CM versus control; p < 0.005). CONCLUSION Ni-Cr microparticles showed less corrosion resistance and lower biocompatibility than compact alloy. This could affect health on long-term exposure, especially in sensitized individuals.
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Affiliation(s)
- Ljubisa Ristic
- Dental Clinic, Military Medical Academy, Belgrade, Serbia
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Park YJ, Song YH, An JH, Song HJ, Anusavice KJ. Cytocompatibility of pure metals and experimental binary titanium alloys for implant materials. J Dent 2013; 41:1251-8. [PMID: 24060476 DOI: 10.1016/j.jdent.2013.09.003] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 09/11/2013] [Accepted: 09/13/2013] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVE This study was performed to evaluate the biocompatibility of nine types of pure metal ingots (Ag, Al, Cr, Cu, Mn, Mo, Nb, V, Zr) and 36 experimental titanium (Ti) alloys containing 5, 10, 15, and 20 wt% of each alloying element. METHODS The cell viabilities for each test group were compared with that of CP-Ti using the WST-1 test and agar overlay test. RESULTS The ranking of pure metal cytotoxicity from most potent to least potent was as follows: Cu>Al>Ag>V>Mn>Cr>Zr>Nb>Mo>CP-Ti. The mean cell viabilities for pure Cu, Al, Ag, V, and Mn were 21.6%, 25.3%, 31.7%, 31.7%, and 32.7%, respectively, which were significantly lower than that for the control group (p<0.05). The mean cell viabilities for pure Zr and Cr were 74.1% and 60.6%, respectively (p<0.05). Pure Mo and Nb demonstrated good biocompatibility with mean cell viabilities of 93.3% and 93.0%, respectively. The mean cell viabilities for all the Ti-based alloy groups were higher than 80% except for Ti-20 Nb (79.6%) and Ti-10 V (66.9%). The Ti-10 Nb alloy exhibited the highest cell viability (124.8%), which was higher than that of CP-Ti. Based on agar overlay test, pure Ag, Cr, Cu, Mn, and V were ranked as 'moderately cytotoxic', whereas the rest of the tested pure metals and all Ti alloys, except Ti-10 V (mild cytotoxicity), were ranked as 'noncytotoxic'. SIGNIFICANCE The results obtained in this study can serve as a guide for the development of new Ti-based alloy implant systems.
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Affiliation(s)
- Yeong-Joon Park
- Department of Dental Materials and MRC for Biomineralization Disorders, School of Dentistry, Chonnam National University, Gwangju 500-757, South Korea.
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Zingler S, Erber R, Lux CJ, Seeberger R, Bister D, Ludwig B. Biocompatibility of gold and stainless steel chains used for forced eruption of impacted teeth – an in vitro investigation. Oral Surg Oral Med Oral Pathol Oral Radiol 2013; 116:159-68. [DOI: 10.1016/j.oooo.2013.02.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 02/06/2013] [Accepted: 02/19/2013] [Indexed: 02/01/2023]
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Grillo CA, Morales ML, Mirífico MV, Fernández Lorenzo de Mele MA. Synergistic cytotoxic effects of ions released by zinc–aluminum bronze and the metallic salts on osteoblastic cells. J Biomed Mater Res A 2013; 101:2129-40. [DOI: 10.1002/jbm.a.34503] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 10/11/2012] [Accepted: 10/17/2012] [Indexed: 11/07/2022]
Affiliation(s)
- Claudia A. Grillo
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA, CCT La Plata‐CONICET), Facultad de Ciencias Exactas, Departamento de Química, Universidad Nacional de La Plata, Casilla de Correo 16, Sucursal 4, 1900 La Plata, Argentina
| | - María L. Morales
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA, CCT La Plata‐CONICET), Facultad de Ciencias Exactas, Departamento de Química, Universidad Nacional de La Plata, Casilla de Correo 16, Sucursal 4, 1900 La Plata, Argentina
| | - María V. Mirífico
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA, CCT La Plata‐CONICET), Facultad de Ciencias Exactas, Departamento de Química, Universidad Nacional de La Plata, Casilla de Correo 16, Sucursal 4, 1900 La Plata, Argentina
- Facultad de Ingeniería, Áreas Departamentales Ingeniería Química y Mecánica, Universidad Nacional de La Plata, Calle 1 esq. 47, 1900 La Plata, Argentina
| | - Mónica A. Fernández Lorenzo de Mele
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA, CCT La Plata‐CONICET), Facultad de Ciencias Exactas, Departamento de Química, Universidad Nacional de La Plata, Casilla de Correo 16, Sucursal 4, 1900 La Plata, Argentina
- Facultad de Ingeniería, Áreas Departamentales Ingeniería Química y Mecánica, Universidad Nacional de La Plata, Calle 1 esq. 47, 1900 La Plata, Argentina
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Wu J, Wang L, He J, Zhu C. In vitro cytotoxicity of Cu2+, Zn2+, Ag+ and their mixtures on primary human endometrial epithelial cells. Contraception 2012; 85:509-18. [DOI: 10.1016/j.contraception.2011.09.016] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 09/15/2011] [Accepted: 09/29/2011] [Indexed: 11/28/2022]
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Wagner W, Sachrajda I, Pułaski Ł, Hałatek T, Dastych J. Application of cellular biosensors for analysis of bioactivity associated with airborne particulate matter. Toxicol In Vitro 2011; 25:1132-42. [DOI: 10.1016/j.tiv.2011.03.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2010] [Revised: 02/28/2011] [Accepted: 03/25/2011] [Indexed: 10/18/2022]
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Passariello C, Puttini M, Virga A, Gigola P. Microbiological and host factors are involved in promoting the periodontal failure of metaloceramic crowns. Clin Oral Investig 2011; 16:987-95. [PMID: 21720749 DOI: 10.1007/s00784-011-0585-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2010] [Accepted: 06/16/2011] [Indexed: 11/27/2022]
Abstract
This study was aimed at looking into the microbiological/inflammatory parameters predicting the periodontal success/failure of fixed prostheses. Microbiological and inflammatory patterns were studied at 102 sites having metaloceramic crowns in place from 3 to 6 years and divided in healthy sites (HS), gingivitis affected (MG), and periodontitis affected (PB). Total bacterial flora and selected indicator species in subgingival plaque were quantified by quantitative real-time PCR. The concentrations of IL-1β, IL-6, and TNF-α were determined in gingival crevicular fluid (GCF) by enzyme-linked immunosorbent assays. The experimental sites showed no significant difference with respect to the age and gender of the patients and to the position of the crown margins. Poor marginal adaptation was significantly higher in MG and PB. The total amounts of bacteria per probing depth showed no significant differences among the three groups and their controls, while both MG and PB sites showed altered patterns in the distribution of specific bacteria. Both MG and PB sites showed significantly higher levels of inflammatory cytokines in GCF. The control teeth of PB subjects showed significantly higher levels of IL-1β as compared to other control sites. Data confirm that the application of metaloceramic crowns is a factor of risk for the development of gingival/periodontal inflammation. This risk is possibly associated with microbiological and host factors that predispose to the onset of periodontal alterations at sites reconstructed with metaloceramic crowns. These factors, once their role is confirmed by longitudinal studies, could be used to set up rapid tests to early predict the onset of periodontal disease at reconstructed sites.
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Affiliation(s)
- Claudio Passariello
- Dipartimento di Sanità Pubblica e Malattie Infettive, Università La Sapienza, Piazzale Aldo Moro 5, 00185 Rome, Italy.
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Reddy NR, Abraham AP, Murugesan K, Matsa V. An invitro analysis of elemental release and cytotoxicity of recast nickel-chromium dental casting alloys. J Indian Prosthodont Soc 2011; 11:106-12. [PMID: 22654350 DOI: 10.1007/s13191-011-0075-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2010] [Accepted: 05/22/2011] [Indexed: 10/18/2022] Open
Abstract
Recasting of the casting alloys affects the composition and elemental release which may have cytotoxic effect different from the pure alloy in the surrounding tissues. An Invitro study was conducted to investigate the elemental release and their cytotoxic effects from commercially available Ni-Cr dental casting alloys, commonly used for fabricating fixed partial dentures. Three Ni-Cr alloys [Wiron 99(A), Ceramet (B), and Hi Nickel CB (C)] were tested. Alloy specimens (disks 3 × 5 mm) were casted and grouped as follows: Group I (A(1)/B(1)/C(1)): 100% pure alloy; Group II (A(2)/B(2)/C(2)): 50% new with 50% recast; and Group III (A(3)/B(3)/C(3)): 100% recast. Disks of each alloy type from each group were transferred to Dulbecco's modified eagle medium and left for 3 days at 37°C in an atmosphere of 5% CO(2). Ni, Cr, Co, Cu and Mo elemental release from metal alloys into culture medium was investigated using Inductively Coupled Plasma Mass Spectrometry. Cytotoxicity was tested using mouse fibroblast cells and MTT Assay. Controls consisted of 6 wells containing cells with no alloy specimens. Data were analyzed by two-way analysis of variance followed by t-test. The total amount of elements released in parts per billion for various casting groups were Group I, A(1)-6.572, B(1)-6.732, C(1)-8.407; Group II, A(2)-22.046, B(2)-26.450, C(2)-29.189; Group III, A(3)-84.554, B(3)-88.359, C(3)-92.264. More amounts of elements were released in Hi Nickel CB than Ceramet and Wiron 99 in all the three test groups. Percentage of viable cells from MTT analysis were Group I, A(1)-62.342, B(1)-61.322 C(1)-60.593, Group II, A(2)-58.699, B(2)-56.494, C(2)-52.688, Group III, A(3)-53.101, B(3)-52.195, C(3)-47.586. The viable cells present in the culture media were more in Wiron 99 than Ceramet and Hi Nickel CB. Elemental release increased with amount of recast alloy. Amongst the three alloys tested Hi Nickel CB had significantly higher elements released compared to Ceramet and Wiron 99 in 100% pure alloys, 50% recast and 100% recast alloys. Wiron 99 showed least element release in 100% pure alloy, 50% recast and 100% recast specimens. 100% pure alloys of all three alloys are less cytotoxic, but their cytotoxicity is more on 50% and 100% re-casted alloys. Out of all three variations of casting Wiron 99 was least cytotoxic, followed by Ceramet and Hi Nickel CB. Recasting of alloys significantly increased the elements released and their cytotoxicity.
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HJALMARSSON L, SMEDBERG JI, WENNERBERG A. Material degradation in implant-retained cobalt-chrome and titanium frameworks. J Oral Rehabil 2010; 38:61-71. [DOI: 10.1111/j.1365-2842.2010.02127.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Huan ZG, Leeflang MA, Zhou J, Fratila-Apachitei LE, Duszczyk J. In vitro degradation behavior and cytocompatibility of Mg-Zn-Zr alloys. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2010; 21:2623-35. [PMID: 20532960 PMCID: PMC2935537 DOI: 10.1007/s10856-010-4111-8] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Accepted: 05/25/2010] [Indexed: 05/09/2023]
Abstract
Zinc and zirconium were selected as the alloying elements in biodegradable magnesium alloys, considering their strengthening effect and good biocompatibility. The degradation rate, hydrogen evolution, ion release, surface layer and in vitro cytotoxicity of two Mg-Zn-Zr alloys, i.e. ZK30 and ZK60, and a WE-type alloy (Mg-Y-RE-Zr) were investigated by means of long-term static immersion testing in Hank's solution, non-static immersion testing in Hank's solution and cell-material interaction analysis. It was found that, among these three magnesium alloys, ZK30 had the lowest degradation rate and the least hydrogen evolution. A magnesium calcium phosphate layer was formed on the surface of ZK30 sample during non-static immersion and its degradation caused minute changes in the ion concentrations and pH value of Hank's solution. In addition, the ZK30 alloy showed insignificant cytotoxicity against bone marrow stromal cells as compared with biocompatible hydroxyapatite (HA) and the WE-type alloy. After prolonged incubation for 7 days, a stimulatory effect on cell proliferation was observed. The results of the present study suggested that ZK30 could be a promising material for biodegradable orthopedic implants and worth further investigation to evaluate its in vitro and in vivo degradation behavior.
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Affiliation(s)
- Z. G. Huan
- Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands
| | - M. A. Leeflang
- Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands
| | - J. Zhou
- Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands
| | - L. E. Fratila-Apachitei
- Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands
| | - J. Duszczyk
- Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands
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Čolić M, Rudolf R, Stamenković D, Anžel I, Vučević D, Jenko M, Lazić V, Lojen G. Relationship between microstructure, cytotoxicity and corrosion properties of a Cu-Al-Ni shape memory alloy. Acta Biomater 2010; 6:308-17. [PMID: 19540942 DOI: 10.1016/j.actbio.2009.06.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Revised: 06/12/2009] [Accepted: 06/16/2009] [Indexed: 10/20/2022]
Abstract
Cu-Al-Ni shape memory alloys (SMAs) have been investigated as materials for medical devices, but their biomedical application is still limited. The aim of this work was to compare the microstructure, corrosion and cytotoxicity in vitro of a Cu-Al-Ni SMA. Rapidly solidified (RS) thin ribbons, manufactured via melt spinning, were used for the tests. The control alloy was a permanent mould casting of the same composition, but without shape memory effect. The results show that RS ribbons are significantly more resistant to corrosion compared with the control alloy, as judged by the lesser release of Cu and Ni into the conditioning medium. These results correlate with the finding that RS ribbons were not cytotoxic to L929 mouse fibroblasts and rat thymocytes. In addition, the RS ribbon conditioning medium inhibited cellular proliferation and IL-2 production by activated rat splenocytes to a much lesser extent. The inhibitory effects were almost completely abolished by conditioning the RS ribbons in culture medium for 4 weeks. Microstructural analysis showed that RS ribbons are martensitic, with boron particles as a minor phase. In contrast, the control Cu-Al-Ni alloy had a complex multiphase microstructure. Examination of the alloy surfaces after conditioning by energy dispersive X-ray and Auger electron spectroscopy showed the formation of Cu and Al oxide layers and confirmed that the metals in RS ribbons are less susceptible to oxidation and corrosion compared with the control alloy. In conclusion, these results suggest that rapid solidification significantly improves the corrosion stability and biocompatibility in vitro of Cu-Al-Ni SMA ribbons.
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Čolić M, Tomić S, Rudolf R, Anžel I, Lojen G. The Response of Macrophages to a Cu-Al-Ni Shape Memory Alloy. J Biomater Appl 2009; 25:269-86. [DOI: 10.1177/0885328209354613] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cu—Al—Ni shape memory alloys (SMAs) have been investigated as materials for medical devices, but little is known about their biocompatibility. The aim of this work was to study the response of rat peritoneal macrophages (PMØ) to a Cu—Al—Ni SMA in vitro, by measuring the functional activity of mitochondria, necrosis, apoptosis, and production of proinflammatory cytokines. Rapidly solidified (RS) thin ribbons were used for the tests. The control alloy was a permanent mold casting of the same composition, but without the shape memory effect. Our results showed that the control alloy was severely cytotoxic, whereas RS ribbons induced neither necrosis nor apoptosis of PMØ. These findings correlated with the data that RS ribbons are significantly more resistant to corrosion compared to the control alloy, as judged by the lesser release of Cu and Ni in the conditioning medium. However, the ribbons generated intracellular reactive oxygen species and upregulated the production of IL-6 by PMØ. These effects were almost completely abolished by conditioning the RS ribbons for 5 weeks. In conclusion, RS significantly improves the corrosion stability and biocompatibility of Cu—Al—Ni SMA. The biocompatibility of this functional material could be additionally enhanced by conditioning the ribbons in cell culture medium.
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Affiliation(s)
- Miodrag Čolić
- Institute of Medical Research, MMA, Crnotravska 17, 11002 Belgrade, Serbia,
| | - Sergej Tomić
- Institute of Medical Research, MMA, Crnotravska 17, 11002 Belgrade, Serbia
| | - Rebeka Rudolf
- University of Maribor, Faculty of Mechanical Engineering Smetanova 17, SI- 2000 Maribor, Slovenia
| | - Ivan Anžel
- University of Maribor, Faculty of Mechanical Engineering Smetanova 17, SI- 2000 Maribor, Slovenia
| | - Gorazd Lojen
- University of Maribor, Faculty of Mechanical Engineering Smetanova 17, SI- 2000 Maribor, Slovenia
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Elshahawy W, Watanabe I, Koike M. Elemental ion release from four different fixed prosthodontic materials. Dent Mater 2009; 25:976-81. [PMID: 19303629 DOI: 10.1016/j.dental.2009.02.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Revised: 02/12/2009] [Accepted: 02/14/2009] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Elemental release is important because it plays a significant role in material biocompatibility. The aim of this study was to investigate the release of metal ions from four fixed prosthodontic materials. METHODS Specimens were prepared using the conventional lost wax technique for gold and nickel-chromium (Ni-Cr) alloys, and by cutting blocks and bar for CAD-CAM ceramic and stainless-steel (St-St) alloy, respectively. All specimens were polished (600grit SiC paper), and ultrasonically cleaned with ethanol for 5min. After they were immersed in 0.9% sodium chloride (NaCl) and 1% lactic acid, and were kept at 37 degrees C for 7 days, the elemental release (mug/cm(2)) from each material was analyzed by using inductively coupled plasma mass spectroscopy. The rate (n=5) was statistically analyzed by ANOVA/Tukey test (p<0.05). Two immersion blank solutions were used as a negative control group. RESULTS Higher elemental release (mean+/-S.D.) of all elements from all materials was evident into the lactic acid solution except for Ag. In the gold alloy, there was significant difference (p<0.05) between Zn and other released elements in the NaCl solution, and it also revealed significant difference between Pd or Ag and Cu which detection value was more than Zn (but no statistical difference) into lactic acid solution. The Ni was significantly more released from Ni-Cr alloy than the other elements into both NaCl and lactic acid solutions. The same was observed for Fe released from St-St alloy. There was more significant release of K than Al from CAD-CAM ceramic in only NaCl solution. SIGNIFICANCE Transient exposure of tested materials to an acidic environment is likely to significantly increase the elemental release from them. The significant higher release of Ni from Ni-Cr alloy, and Zn, Cu from gold alloy was evident.
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Affiliation(s)
- Waleed Elshahawy
- Department of Biomaterials Science, Baylor College of Dentistry, Texas A&M Health Science Center, 3302 Gaston Ave., Dallas, TX 75246, USA.
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Ardlin BI, Lindholm-Sethson B, Dahl JE. Corrosion of dental nickel-aluminum bronze with a minor gold content-mechanism and biological impact. J Biomed Mater Res B Appl Biomater 2009; 88:465-73. [DOI: 10.1002/jbm.b.31143] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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In vitro corrosion and biocompatibility of binary magnesium alloys. Biomaterials 2008; 30:484-98. [PMID: 19000636 DOI: 10.1016/j.biomaterials.2008.10.021] [Citation(s) in RCA: 507] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Accepted: 10/21/2008] [Indexed: 12/11/2022]
Abstract
As bioabsorbable materials, magnesium alloys are expected to be totally degraded in the body and their biocorrosion products not deleterious to the surrounding tissues. It's critical that the alloying elements are carefully selected in consideration of their cytotoxicity and hemocompatibility. In the present study, nine alloying elements Al, Ag, In, Mn, Si, Sn, Y, Zn and Zr were added into magnesium individually to fabricate binary Mg-1X (wt.%) alloys. Pure magnesium was used as control. Their mechanical properties, corrosion properties and in vitro biocompatibilities (cytotoxicity and hemocompatibility) were evaluated by SEM, XRD, tensile test, immersion test, electrochemical corrosion test, cell culture and platelet adhesion test. The results showed that the addition of alloying elements could influence the strength and corrosion resistance of Mg. The cytotoxicity tests indicated that Mg-1Al, Mg-1Sn and Mg-1Zn alloy extracts showed no significant reduced cell viability to fibroblasts (L-929 and NIH3T3) and osteoblasts (MC3T3-E1); Mg-1Al and Mg-1Zn alloy extracts indicated no negative effect on viabilities of blood vessel related cells, ECV304 and VSMC. It was found that hemolysis and the amount of adhered platelets decreased after alloying for all Mg-1X alloys as compared to the pure magnesium control. The relationship between the corrosion products and the in vitro biocompatibility had been discussed and the suitable alloying elements for the biomedical applications associated with bone and blood vessel had been proposed.
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Taira M, Toguchi MS, Hamada Y, Okazaki M, Takahashi J, Ito R, Toyosawa S, Ijyuin N. Studies on cytotoxicity of nickel ions using C3H10T1/2 fibroblast cells. J Oral Rehabil 2008. [DOI: 10.1111/j.1365-2842.2000.00608.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Brushing-induced surface roughness of nickel-, palladium-, and gold-based dental casting alloys. J Prosthet Dent 2008; 99:455-60. [DOI: 10.1016/s0022-3913(08)60107-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Suguro H, Asano M, Kaneko Y, Omagari D, Ogiso B, Moro I, Komiyama K. Characterization of human dental pulp-derived cell lines. Int Endod J 2008; 41:609-16. [PMID: 18479370 DOI: 10.1111/j.1365-2591.2008.01409.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
AIM To establish and characterize different types of fibroblastic cell lines derived from dental pulp tissue. METHODOLOGY Human dental pulp tissue-derived cells were transfected with SV40 large T antigen by Lipofectamine transfection method. Geneticin (G418)-resistant cells were selected and different cell lines were established by a limiting dilution method. To characterize the lineages of cells, each clone was immunofluorescently stained by anti-fibroblast, anti-vimentin, anti-collagen type I and type III antibodies. Total RNA was extracted from each clone and subjected to a differential display experiment. RESULTS By transfecting SV40 large T antigen, nine different cell clones were obtained. All these cell clones were positively stained by anti-fibroblast, anti-vimentin, anti-collagen type I and type III antibodies. With differential display experiment, eight different genes, the expression levels of these genes were varied amongst each cell clone, were detected. After sequencing and database search, one gene was revealed to be identical to T-cell marker, Thy-1. Thy-1 expression in dental pulp tissue was confirmed by immunohistochemical staining. CONCLUSION Fibroblastic cell lines derived from human dental pulp tissue possessed different gene expression profiles suggesting the existence of subpopulations.
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Affiliation(s)
- H Suguro
- Department of Endodontics, Dental Research Center, Nihon University School of Dentistry, Nihon Univeristy, Chiyoda-ku, Tokyo, Japan
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Relationship between radial diffusion of copper ions released from a metal disk and cytotoxic effects. Comparison with results obtained using extracts. Bioelectrochemistry 2007; 72:94-101. [PMID: 18191620 DOI: 10.1016/j.bioelechem.2007.11.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Revised: 08/16/2007] [Accepted: 11/18/2007] [Indexed: 11/22/2022]
Abstract
The extended use of metallic biomaterials yields to increasing sources of metal ions within the human body and may result in inflammation of the surrounding tissues, cell damage, and cancer. The aim of this study was to investigate the relationship between the radial diffusion of metal ions released from a metal disk by the corrosion process and the toxic effect on a cell line that grew around it. Results obtained with the metal disks (direct contact) were compared with assays made with extracts obtained from the dissolution of a metallic sample ex situ and then added to the cell culture to elucidate the cause of apparent inconsistencies in previous reports. The change of copper concentration due to corrosion and transient diffusion of copper ions from the copper disks into the cell line was evaluated according to Fick's 2nd law. Surviving cells distribution was interpreted considering the radial and time-dependence of copper concentration. We concluded that the toxic effect on those cells close to metallic biomaterials may be underestimated when only the extract methodology is employed for cytotoxic tests or when during the experiments with disks the presence of concentration gradients and the non-homogeneous distribution of dead cells are disregarded.
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Geurtsen W. Biocompatibility of dental casting alloys. CRITICAL REVIEWS IN ORAL BIOLOGY AND MEDICINE : AN OFFICIAL PUBLICATION OF THE AMERICAN ASSOCIATION OF ORAL BIOLOGISTS 2007; 13:71-84. [PMID: 12097239 DOI: 10.1177/154411130201300108] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Most cast dental restorations are made from alloys or commercially pure titanium (cpTi). Many orthodontic appliances are also fabricated from metallic materials. It has been documented in vitro and in vivo that metallic dental devices release metal ions, mainly due to corrosion. Those metallic components may be locally and systemically distributed and could play a role in the etiology of oral and systemic pathological conditions. The quality and quantity of the released cations depend upon the type of alloy and various corrosion parameters. No general correlation has been observed between alloy nobility and corrosion. However, it has been documented that some Ni-based alloys, such as beryllium-containing Ni alloys, exhibit increased corrosion, specifically at low pH. Further, microparticles are abraded from metallic restorations due to wear. In sufficient quantities, released metal ions-particularly Cu, Ni, Be, and abraded microparticles-can also induce inflammation of the adjacent periodontal tissues and the oral mucosa. While there is also some in vitro evidence that the immune response can be altered by various metal ions, the role of these ions in oral inflammatory diseases such as gingivitis and periodontitis is unknown. Allergic reactions due to metallic dental restorations have been documented. Ni has especially been identified as being highly allergenic. Interestingly, from 34% to 65.5% of the patients who are allergic to Ni are also allergic to Pd. Further, Pd allergy always occurrs with Ni sensitivity. In contrast, no study has been published which supports the hypothesis that dental metallic materials are mutagenic/genotoxic or might be a carcinogenic hazard to man. Taken together, very contradictory data have been documented regarding the local and systemic effects of dental casting alloys and metallic ions released from them. Therefore, it is of critical importance to elucidate the release of cations from metallic dental restorations in the oral environment and to determine the biological interactions of released metal components with oral and systemic tissues.
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Affiliation(s)
- Werner Geurtsen
- Department of Conservative Dentistry and Periodontology, Medical University Hannover, Hannover, Germany.
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Imai K, Nakamura M. In vitro embryotoxicity testing of metals for dental use by differentiation of embryonic stem cell test. Congenit Anom (Kyoto) 2006; 46:34-8. [PMID: 16643597 DOI: 10.1111/j.1741-4520.2006.00099.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We examined embryotoxicity using the embryonic stem cell test (EST) protocol. Tests were conducted using standard reagents for the atomic absorption measurement of 11 metal ions, silver, cobalt, chromium, copper, mercury, nickel, palladium, antimony, tin, vanadium, and zinc from among metals comprising dental alloys. In addition, for four metals like silver, cobalt, chromium, and nickel, the tests were also conducted using a test solution extracted from powder in the cell culture medium. The embryotoxic potential was obtained from a biostatistics-based prediction model, which was calculated from three endpoints, the ID50, IC50ES and IC(50)3T3. Data with the standard reagents showed that chromium and mercury ions corresponded to class 3, that is, having a strong embryotoxicity, while antimony, tin, and vanadium ions exhibited a weak embryotoxicity. The other metal ions demonstrated no embryotoxicity. On the other hand, when extracts of metal powder in cell culture solutions were used, silver exhibited a weak embryotoxicity while all other metals exhibited no embryotoxicity. In the future, it will be important to clarify the embryotoxicity of the many dental materials that are in use today. In addition, it is necessary to develop substances to ensure they have no toxicity before use in dental applications.
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Affiliation(s)
- Koichi Imai
- Department of Biomaterials, Osaka Dental University, Hirakata-city, Osaka, Japan.
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Venugopalan R, Messer RLW. The effect of a microcarrier suspension cell culture system on polarization measurements from Ni–Cr dental casting alloys. Dent Mater 2005; 21:993-8. [PMID: 16181670 DOI: 10.1016/j.dental.2005.01.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2004] [Accepted: 01/12/2005] [Indexed: 11/22/2022]
Abstract
OBJECTIVES Recent research has demonstrated that cells/cellular components can influence the corrosion or degradation of the implant material in addition to being challenged by the cytotoxic by-products the implant material may release. The overall objective of this research was to modify a microcarrier suspension cell culture system to incorporate an active corrosion experimental capacity. METHODS The ability to conduct polarization experiments on two Ni-Cr dental casting alloys under the following environmental conditions: media only, media plus serum, media plus serum and antibiotics (complete media), complete media with microcarriers, and complete media with cells grown on microcarriers; was evaluated during this initial study. RESULTS Results obtained were reproducible within sample groups (95% confidence level) indicating the precision of the corrosion set-up under all environmental conditions. These studies also show that media with serum and antibiotics (complete media) induced a significantly higher corrosion rate (95% confidence level) for both materials compared to the other test conditions. SIGNIFICANCE Future experiments will focus on cytotoxic effects caused by parametrically controlled corrosion experiments on the suspension cell cultures, including co-cultures.
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Affiliation(s)
- Ramakrishna Venugopalan
- Neuro-Modulation R&D, Codman and Shurtleff, A J&J Company, 325 Paramount Drive, Raynham, MA 02767, USA
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Abstract
The expansion of the European Union is bringing new types of metal-ceramic alloys to the market, i.e. alloys probably unknown in Western-European dentistry. The aim of this study was to investigate recent developments and "classic" alloy compositions (one iron and two cobalt alloys, unalloyed titanium and an experimental titanium-zirconium alloy, and one gold alloy containing copper and zinc). The alloys and titanium were subject to static immersion in a 0.1 mol l(-1) solution of saline lactic acid before and after oxidation, hence simulating the temperature cycles for the application of ceramic to metal. The greatest amounts of released metal ions were found in the electrolytes of the oxidized gold alloy and of a cobalt alloy not exposed to high-temperature oxidation. Corrosion of the titanium and alloy surfaces was related to the condition of the specimen. The irritation potentials of some metal ions found in the electrolyte were investigated by performing the hen's egg test-chorio-allantoic membrane (HET-CAM) procedure with 1 mmol l(-1) solutions of Ce(3+), Co(2+), Cu(2+), Zn(2+), Fe(2+), and Ti(4+) ions. The irritation potential of the electrolyte of the oxidized gold alloy with a high concentration of metal elements was also investigated. Of these solutions, only the 1 mmol l(-1) Cu(2+) solution was graded as slightly irritating.
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Affiliation(s)
- Berit I Ardlin
- Scandinavian Institute of Dental Materials, Haslum, Norway.
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Abstract
STATEMENT OF PROBLEM Cytotoxicity of cast alloys depends on their composition and element release, which may be affected by recasting of the alloy. PURPOSE This study investigated the effect of recasting on the element release and cytotoxicity of 5 base metal alloys. MATERIAL AND METHODS The alloys tested consisted of: 2 Ni-Cr (Remanium CS and Wiron 99); a Ni-Cr with Cu (CB Soft); a Co-Cr (Wirobond C); and a Cu-base (Thermobond). Alloy specimens (disks 3 x 5 mm) were cast as follows: 100% new alloy; 50% new with 50% recast; and 100% recast (n = 6). Cytotoxicity was tested using Balb/C 3T3 fibroblasts and the MTT assay. Six replicates were tested for each alloy, and the controls consisted of 6 wells containing cells with no alloy specimens. The release of elements from the alloys into culture medium was also investigated. The data were analyzed by 2-way analysis of variance (ANOVA) followed by the Tukey Honestly Significant Difference test (family error rate =.05). RESULTS At all 3 variations of casting, Remanium CS and Wiron 99 were the least cytotoxic, followed by Wirobond C, CB Soft, and Thermobond. ANOVA revealed significant differences between the groups (P <.001). Post hoc analysis showed that overall, Thermobond was significantly more cytotoxic than all of the other alloys tested (P <.05). For the 100% new alloy groups the cytotoxicity of Co-Cr alloy Wirobond C was similar to that of the Ni-Cr alloys Remanium CS and Wiron 99; however, when the alloys were recast, Wirobond C became significantly more cytotoxic and as toxic as the Ni-Cr alloy containing Cu (CB Soft). Moreover, recasting significantly increased the cytotoxicity of all the alloys (P <.05) and the amounts of elements released from them. CONCLUSION The Cu content in an alloy increased its cytotoxicity level remarkably. Recasting of alloys significantly increased their cytotoxicity level. The Co-Cr alloy was more adversely affected by the recasting than the Ni-Cr alloys.
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Affiliation(s)
- Ahmad S Al-Hiyasat
- Department of Restorative Dentistry, Jordan University of Science and Technology, Irbid 22110, Jordan.
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Abstract
Metallic medical devices undergo degradation in vivo and the degradation products affect the chemistry and biological responses of cells and tissues in the immediate vicinity. The responses vary with the metal and cell type. In the current study, we examined the effects of several metals on a human monocytic cell line. Monocytes are important effector cells capable of responding rapidly to inflammatory and immune stimuli in a variety of ways, including production of inflammatory proteins, differential expression of surface adhesion molecules, enhanced phagocytic activity, and activation and differentiation to macrophages. Cells were exposed in the presence of (14)C-acetate to titanium, nickel, chromium, copper, or cobalt or vanadium at concentrations that were subinhibitory or inhibitory based on cellular mitochondrial dehydrogenase activity. Cell lipids were then extracted, separated by thin layer chromatography, and quantitated by liquid scintillation spectrometry. Total cell protein also was measured. Titanium reduced cell protein content at concentrations that were noninhibitory to mitochondrial dehydrogenase activity, whereas neither chromium nor cobalt affected protein amounts at dehydrogenase-inhibitory concentrations. In cells exposed to vanadium, the protein- and dehydrogenase-inhibitory concentrations were similar. The major effects on cell lipids appeared to occur in the neutral lipids, although chromium, cobalt, and titanium produced changes in some major phospholipids. These results suggest that metals differentially affect various metabolic pathways in THP-1 cells, perhaps related to their abilities to enter the cells or interact with the membrane. These alterations to the cells may affect the cells' abilities to respond to various stimuli that can damage the tissues.
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Affiliation(s)
- George S Schuster
- Department of Oral Biology and Maxillofacial Pathology, Medical College of Georgia, School of Dentistry, Augusta, Georgia 30912-1126, USA.
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Kao CT, Ding SJ, Chen YC, Huang TH. The anticorrosion ability of titanium nitride (TiN) plating on an orthodontic metal bracket and its biocompatibility. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2003; 63:786-92. [PMID: 12418025 DOI: 10.1002/jbm.10484] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Typically, an orthodontic metal bracket is made from stainless steel. It has been shown that such metal may corrode in an acid- and chloride-rich environment. The purpose of the current study was to investigate a titanium nitride (TiN) ion-plated stainless steel orthodontic bracket's anticorrosion properties and compare its biocompatibility with that of non-TiN-plated brackets. The stainless-steel brackets studied here were tested in acidic artificial saliva. The plated metal bracket was produced by the titanium nitride (TiN) ion-plating method. The TiN-plating on the bracket surface was demonstrated to be successful by EDX analysis. The quantity of metallic-ion release under test immersion solutions was analyzed by atomic absorption spectrophotometry. Both TiN- and non-TiN-plated brackets may release detectable ions into the test solution, including nickel, chromium, manganese, copper, and iron (ferric). The anticorrosion ability of the plated bracket was analyzed by means of inductively coupled plasma atomic emission spectroscopy. The results revealed that the TiN-plated metal bracket did not increase the anticorrosion ability of the standard bracket. The biocompatibility of the TiN plating versus the standard bracket material resulting from bracket immersion in the test solution revealed no toxicity on U2OS cells using a methylthiazole tetrazolium (MTT) colorimetric assay. Clearly, the search for an improved technique for enhancing the anticorrosion ability of the normal metal orthodontic bracket should be continued.
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Affiliation(s)
- Chia-Tze Kao
- Institute of Stomatology, Chung Shan Medical and Dental College, 110, Section 1, Chien Kuo N Road, Taichung, Taiwan, PO 402
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Wataha JC, Lockwood PE, Bouillaguet S, Noda M. In vitro biological response to core and flowable dental restorative materials. Dent Mater 2003; 19:25-31. [PMID: 12498893 DOI: 10.1016/s0109-5641(02)00012-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVES In vitro cytotoxicities of commercially available core and flowable dental restorative materials were assessed and compared to traditional resin composites. Our hypothesis was that the increased resin diluents added to achieve higher flow in flowables would increase cytotoxicities, whereas the higher filler content of core materials would decrease cytotoxicities relative to traditional resin composites. METHODS Specimens were made under aseptic conditions, then extracted into an artificial saliva solution for 0-4 weeks, to assess the effect of aging on cytotoxicity. After extraction, specimens were tested for cytotoxicity in vitro using Balb/c fibroblasts in direct contact format. Cells were exposed to the materials for 48h, after which the mitochondrial activity of the cells was measured (MTT method). Cellular activity was normalized to Teflon negative controls. RESULTS Core materials were uniformly and severely (<50% of Teflon cellular activity) cytotoxic initially, but several materials (Corepaste, Definite core) improved somewhat with aging in artificial saliva. Flowable materials were uniformly and severely cytotoxic with no trend toward improvement with aging. The Definite-flow was the least cytotoxic of the flowable materials, but it too was severely cytotoxic. SIGNIFICANCE Commercially available core and flowable restorative materials showed severe in vitro cytotoxicities that are worse than some traditional composites and most dental casting alloys and amalgams used today. Of particular note was the persistent cytotoxicity of these materials after 4 weeks of extraction with artificial saliva. These cytotoxicities indicate a continuing release of mass from these materials at levels that have biological relevance in vitro. In vivo relevance of these cytotoxicities is less clear, but these results indicate a higher biological risk for these materials compared to traditional materials that exhibit less initial toxicity and improve with aging time.
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Affiliation(s)
- John C Wataha
- Department of Oral Rehabilitation, School of Dentistry, Medical College of Georgia, Augusta, GA 30912-1260, USA.
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Wataha JC, Lockwood PE, Noda M, Nelson SK, Mettenburg DJ. Effect of toothbrushing on the toxicity of casting alloys. J Prosthet Dent 2002; 87:94-8. [PMID: 11807490 DOI: 10.1067/mpr.2002.121237] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
STATEMENT OF PROBLEM The biological properties of casting alloys have been assessed largely under passive conditions. The effect of common intraoral stresses such as brushing, toothpastes, and low pH on alloy toxicity are not known. PURPOSE This study assessed the toxicity of 5 types of casting alloys commonly used in prosthodontics after toothbrushing, brushing in an acidic environment, or brushing with toothpaste. These toxicities were compared with those observed without any brushing. MATERIAL AND METHODS Au-Pt, Au-Pd, Pd-Cu-Ga, Ni-Cr-Be, and Ni-Cr (no Be) alloys were brushed for 48 hours in a toothbrushing machine at 90 strokes/minute and 200g force. Alloys were brushed with either saline at pH 7, saline at pH 4 (acidified with sodium lactate), or saline with 1:7 (wt/wt) toothpaste. After the brushing regimen, the cytotoxicity of the alloys was assessed in a standard in vitro test. Cytotoxicities of the alloys after different brushing treatments were compared with unbrushed (control) specimens. Analysis of variance (ANOVA) and Tukey multiple comparison intervals (alpha=.05) were used to identify significant differences among brushing conditions. RESULTS Brushing at pH 7 significantly increased the toxicity of the Pd-Cu-Ga alloy (15% to 20% over unbrushed specimens). Brushing at pH 4 increased the toxicity of the Au-Pt and Au-Pd alloys by 30% and the Pd-Cu-Ga alloy by >40%. The Ni-based alloys were not affected by acid. After being brushed with toothpaste, both Ni-based alloys were significantly more toxic, but Ni-Cr-Be was the worst, increasing more than 60% in toxicity over the controls. The toxicity of the Au-Pd alloy also increased significantly (15%). CONCLUSION Brushing dental casting alloys may increase their cytotoxicity in vitro, but the increase depends heavily on the alloy type and brushing condition.
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Affiliation(s)
- John C Wataha
- Department of Oral Rehabilitation, School of Dentistry, Medical College of Georgia, Augusta, 30912-1260, USA.
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45
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Wataha JC, Nelson SK, Lockwood PE. Elemental release from dental casting alloys into biological media with and without protein. Dent Mater 2001; 17:409-14. [PMID: 11445208 DOI: 10.1016/s0109-5641(00)00099-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE The objective of this study was to determine the role of proteins in affecting elemental release from a variety of clinically available dental casting alloys. An important role for proteins was suspected based on previous reports about the corrosion of stainless steel and the cytotoxicity of alloys after exposure to a saline-protein solution. METHODS Clinically available alloys with compositions ranging from 0 to 94at.% noble elements were exposed for 1 week to either saline, saline with 3% bovine serum albumin (BSA), or complete cell-culture medium with 3% serum. Atomic absorption spectrophotometry was used to measure the release of elements from the alloys. Elemental release was normalized for the exposed surface area of the alloys. RESULTS In general, more elemental release occurred into the saline-BSA solution compared to saline alone for all released elements (Ag, Cu, Pd, and Zn) except for Ni. Ni release from the NiCr alloy was lower in the presence of BSA. Each element responded somewhat differently with Pd being the least predictable in its behavior. Elemental release was less in the cell-culture medium than in the saline-BSA solution for most elements. For alloys which released multiple elements, all elements responded similarly but not identically to the presence of protein. A high elemental release during exposure to the saline-BSA solution correlated with a low alloy cytotoxicity post-exposure to the saline-BSA. SIGNIFICANCE This study demonstrates the importance of defining exactly the composition of biological solutions used to assess in vitro corrosion and biocompatibility of dental casting alloys. Other molecules in addition to proteins appeared to be critical to the corrosion of these alloys in vitro.
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Affiliation(s)
- J C Wataha
- Medical College of Georgia School of Dentistry, Augusta, GA 30912-1260, USA.
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46
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Schuster U, Schmalz G, Thonemann B, Mendel N, Metzl C. Cytotoxicity testing with three-dimensional cultures of transfected pulp-derived cells. J Endod 2001; 27:259-65. [PMID: 11485263 DOI: 10.1097/00004770-200104000-00004] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
SV40 large T-antigen-transfected bovine pulp-derived cells were grown three-dimensionally on polyamide meshes. For optimal cell growth, various cell numbers and mesh coatings were tested. Next the three-dimensional cultures were used in a dentin barrier test device, and the system was evaluated by testing a set of dental filling materials. After 24 hr exposure with or without perfusion of the pulpal part of the test device, cell survival was evaluated using an MTT assay. In all experiments pulp-derived cells transfected with SV40 large T-antigen grew three-dimensionally on polyamide meshes and showed growth kinetics similar to those on cell culture plates with lag, log, and plateau phases (reached after about 14 days of incubation). Cross-sections of the three-dimensional cell cultures revealed about 15 to 20 cell layers. In vitro cytotoxicity tests resulted in cell survival rates which are in good agreement with in vivo data and with results obtained from cytotoxicity tests with three-dimensional cultures of human foreskin fibroblasts.
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Affiliation(s)
- U Schuster
- Department of Operative Dentistry and Periodontology, University of Regensburg, Germany
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Locci P, Lilli C, Marinucci L, Calvitti M, Belcastro S, Bellocchio S, Staffolani N, Guerra M, Becchetti E. In vitro cytotoxic effects of orthodontic appliances. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2000; 53:560-7. [PMID: 10984705 DOI: 10.1002/1097-4636(200009)53:5<560::aid-jbm16>3.0.co;2-j] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The objective of this study was to evaluate the effects of an orthodontic appliance and of its components (brackets, bands, and arch wires) on some cell functions. Fibroblasts were cultured either in the presence of one unwashed orthodontic appliance, or one orthodontic appliance immersed in MEM for 28 days before use (washed appliance), or in the presence of MEM in which the appliances had been immersed. At the end of in vitro maintenance, morphological studies were carried out with SEM and TEM. Cell proliferation and GAG synthesis and secretion by radio-labeled precursors were assessed. The data indicated that unwashed appliances were more cytotoxic than washed ones. Moreover, the arch wire was the most biocompatible component of the orthodontic appliance, and the bracket was the least biocompatible. A comparative study into the effects on cell proliferation of the most common metal ions released by the appliances was also carried out. At the concentration released by one orthodontic appliance immersed for 28 days, the highest reduction in DNA synthesis was observed in the presence of Cu(++).
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Affiliation(s)
- P Locci
- Department of Experimental Medicine and Biochemical Sciences, University of Perugia, Italy.
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48
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Koch MJ, García-Godoy F. The clinical performance of laboratory-fabricated crowns placed on first permanent molars with developmental defects. J Am Dent Assoc 2000; 131:1285-90. [PMID: 10986829 DOI: 10.14219/jada.archive.2000.0382] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Young permanent molars with developmental enamel defects commonly are treated with stainless steel crowns. However, allergic reactions to nickel and chromium have been reported by some patients. The literature contains no evaluations of alternative treatments. METHODS In a retrospective study, the authors evaluated the clinical performance of cast gold crowns and tooth-colored composite or ceramic crowns placed on first permanent molars with developmental defects in children 6 to 8 years of age. A total of 41 molars were prepared. After crown preparation, an impression was made, and crowns of cast gold, Artglass (J.F. Jelenko & Co.) composite or Empress (Ivoclar) leucite-containing ceramic were fabricated and clinically evaluated every six months for a period ranging from two to five years postoperatively (mean three years). RESULTS After two to five years, all crowns were fully retained. The marginal adaptation of 39 of the 41 crowns was rated excellent, and the marginal adaptation of the remaining two crowns (both gold) received acceptable ratings. In two cast gold crowns, the margins were subgingival at cementation; the remaining 39 crowns had supragingival margins at the time of luting. By the end of the second year, all margins were supragingival. All teeth were vital and asymptomatic at all evaluation points. No secondary caries was recorded. Neither gingival inflammation nor loss of vertical dimension was recorded in any case. All crowns were well-accepted by the patients and their parents. CONCLUSIONS Laboratory-fabricated crowns can be used for the treatment of young permanent molars with developmental defects. CLINICAL IMPLICATIONS Cast gold, composite or ceramic crowns can be used successfully to treat developmental defects of first permanent molars in children.
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Affiliation(s)
- M J Koch
- Department of Conservative Dentistry and Periodontology, Dental School, University of Heidelberg, Germany
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49
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Abstract
STATEMENT OF PROBLEM Dental casting alloys are widely used in applications that place them into contact with oral tissues for many years. With the development of new dental alloys over the past 15 years, many questions remain about their biologic safety. Practitioners must choose among hundreds of alloy compositions, often without regard to biologic properties. PURPOSE This article is an evidence-based tutorial for clinicians. Concepts and current issues relevant to the biologic effects of dental casting alloys are presented. SUMMARY The single most relevant property of a casting alloy to its biologic safety is its corrosion. Systemic and local toxicity, allergy, and carcinogenicity all result from elements in the alloy being released into the mouth during corrosion. Little evidence supports concerns of casting alloys causing systemic toxicity. The occurrence of local toxic effects (adjacent to the alloy) is not well documented, but is a higher risk, primarily because local tissues are exposed to much higher concentrations of released metal ions. Several elements such as nickel and cobalt have relatively high potential to cause allergy, but the true risk of using alloys containing these elements remains undefined. Prudence dictates that alloys containing these elements be avoided if possible. Several elements in casting alloys are known mutagens, and a few such as beryllium and cadmium are known carcinogens in different chemical forms. Despite these facts, carcinogenic effects from dental casting alloys have not been demonstrated. Prudent practitioners should avoid alloys containing these known carcinogens. CONCLUSION To minimize biologic risks, dentists should select alloys that have the lowest release of elements (lowest corrosion). This goal can be achieved by using high-noble or noble alloys with single-phase microstructures. However, there are exceptions to this generality, and selection of an alloy should be made on a case-by-case basis using corrosion and biologic data from dental manufacturers.
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Affiliation(s)
- J C Wataha
- Medical College of Georgia, School of Dentistry, Augusta, Ga., USA.
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50
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Wataha JC, Lockwood PE, Frazier KB, Khajotia SS. Effect of toothbrushing on elemental release from dental casting alloys. J Prosthodont 1999; 8:245-51. [PMID: 10895676 DOI: 10.1111/j.1532-849x.1999.tb00046.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
PURPOSE This study assessed the effect of toothbrushing on the elemental release from common dental casting alloys. MATERIALS AND METHODS A Au-Pt high-noble alloy, a Au-Pd high-noble alloy, a Pd-Cu-Ga noble alloy, and a Ni-Cr base-metal alloy were placed into a biological medium for 1 week to allow equilibration of elemental release, then brushed for 30 minutes at 90 strokes/min under 200 g of force with a soft toothbrush. The brushing was performed in neutral saline or lactic acid at pH 4 with or without toothpaste. The alloys were then transferred back into a biological medium for 1 week. Atomic absorption spectroscopy was used to measure the mass lost from each alloy during and in the week after brushing. Mass loss was expressed as micrograms per square centimeter of alloy surface, and the various brushing conditions were compared by analysis of variance and Tukey multiple comparison intervals (alpha = 0.05). RESULTS During brushing, element release increased significantly over nonbrushed controls for all alloys except the Ni-Cr. Toothpastes, acidic solutions, or combinations of these conditions with toothbrushing further enhanced elemental release, but Ni release from the Ni-Cr alloy increased the most (30-fold). In the week after brushing, brushing alone increased elemental release only from the Ni-Cr alloy. However, toothpastes and acidic solutions increased elemental release for all alloys significantly, except for the Au-Pd alloy. In general, elemental release during brushing was far greater than in the week after brushing. CONCLUSIONS Under the conditions of this study, toothbrushing increased the elemental release from dental casting alloys.
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Affiliation(s)
- J C Wataha
- Department of Oral Rehabilitation, Medical College of Georgia, Augusta 30912-1260, USA.
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