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Ohlsson E, Bolay C, Arabulan S, Galler KM, Buchalla W, Schmalz G, Widbiller M. In-vitro-cytotoxicity of self-adhesive dental restorative materials. Dent Mater 2024; 40:739-746. [PMID: 38403539 DOI: 10.1016/j.dental.2024.02.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 01/05/2024] [Accepted: 02/12/2024] [Indexed: 02/27/2024]
Abstract
OBJECTIVES Although the introduction of self-adhesive composites in restorative dentistry is very promising, the innovation of new materials also presents challenges and unknowns. Therefore, the aim of this study was to investigate the cytotoxicity of four different self-adhesive composites (SAC) in vitro and to compare them with resin-modified glass ionomer cements (RM-GIC), a more established group of materials. METHODS Samples of the following materials were prepared according to ISO 7405/10993-12 and eluted in cell culture medium for 24 h at 37 °C: Vertise Flow, Fusio Liquid Dentin, Constic, Surefil One, Photac Fil and Fuji II LC. Primary human pulp cells were obtained from extracted wisdom teeth and cultured for 24 h with the extracts in serial dilutions. Cell viability was evaluated by MTT assay, membrane disruption was quantified by LDH assay and apoptosis was assessed by flow cytometry after annexin/PI staining. RESULTS Two SAC (Constic and Vertise Flow) and one RM-GIC (Photac Fil) significantly reduced cell viability by more than 30% compared to the untreated control (p < 0.001). Disruptive cell morphological changes were observed and the cells showed signs of late apoptosis and necrosis in flow cytometry. Membrane disruption was not observed with any of the investigated materials. CONCLUSION Toxic effects occurred independently of the substance group and need to be considered in the development of materials with regard to clinical implications. CLINICAL SIGNIFICANCE SAC have many beneficial qualities, however, the cytotoxic effects of certain products should be considered when applied in close proximity to the dental pulp, as is often required.
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Affiliation(s)
- Ella Ohlsson
- Department of Operative Dentistry and Periodontology, Friedrich-Alexander-University Erlangen-Nürnberg, Glückstraße 11, 91054 Erlangen, Germany
| | - Carola Bolay
- Department of Conservative Dentistry and Periodontology, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Sevgi Arabulan
- Department of Pedodontics, Ege University, Ege University Campus, 35040 Izmir, Turkey
| | - Kerstin M Galler
- Department of Operative Dentistry and Periodontology, Friedrich-Alexander-University Erlangen-Nürnberg, Glückstraße 11, 91054 Erlangen, Germany
| | - Wolfgang Buchalla
- Department of Conservative Dentistry and Periodontology, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Gottfried Schmalz
- Department of Conservative Dentistry and Periodontology, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany; Department of Periodontology, University of Bern, 3012 Bern, Switzerland
| | - Matthias Widbiller
- Department of Conservative Dentistry and Periodontology, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany.
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Heyder M, Kranz S, Beck J, Wettemann M, Hennig CL, Schulze-Späte U, Sigusch BW, Reise M. Influence of Layer Thickness and Shade on the Transmission of Light through Contemporary Resin Composites. MATERIALS (BASEL, SWITZERLAND) 2024; 17:1554. [PMID: 38612069 PMCID: PMC11012366 DOI: 10.3390/ma17071554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 03/22/2024] [Accepted: 03/26/2024] [Indexed: 04/14/2024]
Abstract
BACKGROUND Material-dependent parameters have an important impact on the efficiency of light polymerization. The present in vitro study aimed to investigate the influence of the increment thickness and shade of nano- and nanohybrid resin composites on the transmission of curing light. METHODS Three contemporary resin composites were evaluated: Tetric EvoCeram® (TEC); Venus Diamond® (VD); and Filtek Supreme XTE® (FS XTE). Light transmission (LT) was recorded in accordance with the sample thickness (0.5 to 2.7 mm) and the shade. Polymerized samples were irradiated for 10 s each using the high-power LED curing light Celalux 2 (1900 mW/cm2). LT was simultaneously recorded using the MARC Patient Simulator (MARC-PS). RESULTS LT was strongly influenced by the composite layer thickness. For 0.5 mm-thick samples, a mean power density of 735 mW/cm2 was recorded at the bottom side. For the 2.7 mm samples, a mean power density of 107 mW/cm2 was measured. Only LT was markedly reduced in the case of darker shades. From A1 to A4, LT decreased by 39.3% for FS XTE and 50.8% for TEC. Dentin shades of FS XTE and TEC (A2, A4) showed the lowest LT. CONCLUSIONS The thickness and shade of resin composite increments strongly influences the transmission of curing light. More precise information about these parameters should be included in the manufacture manual.
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Affiliation(s)
- Markus Heyder
- Department of Conservative Dentistry and Periodontology, Center of Dental Medicine, Jena University Hospitals, 07743 Jena, Germany; (M.H.); (J.B.); (M.R.)
| | - Stefan Kranz
- Department of Conservative Dentistry and Periodontology, Center of Dental Medicine, Jena University Hospitals, 07743 Jena, Germany; (M.H.); (J.B.); (M.R.)
| | - Julius Beck
- Department of Conservative Dentistry and Periodontology, Center of Dental Medicine, Jena University Hospitals, 07743 Jena, Germany; (M.H.); (J.B.); (M.R.)
| | - Marlene Wettemann
- Department of Conservative Dentistry and Periodontology, Center of Dental Medicine, Jena University Hospitals, 07743 Jena, Germany; (M.H.); (J.B.); (M.R.)
| | - Christoph-Ludwig Hennig
- Department of Orthodontics, Center of Dental Medicine, Jena University Hospital, 07743 Jena, Germany;
| | - Ulrike Schulze-Späte
- Section of Geriodontics, Department of Conservative Dentistry and Periodontology, Center of Dental Medicine, Jena University Hospitals, 07743 Jena, Germany;
| | - Bernd W. Sigusch
- Department of Conservative Dentistry and Periodontology, Center of Dental Medicine, Jena University Hospitals, 07743 Jena, Germany; (M.H.); (J.B.); (M.R.)
| | - Markus Reise
- Department of Conservative Dentistry and Periodontology, Center of Dental Medicine, Jena University Hospitals, 07743 Jena, Germany; (M.H.); (J.B.); (M.R.)
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Mokeem LS, Martini Garcia I, Balhaddad AA, Lan Y, Seifu D, Weir MD, Melo MA. Multifunctional Dental Adhesives Formulated with Silane-Coated Magnetic Fe 3O 4@m-SiO 2 Core-Shell Particles to Counteract Adhesive Interfacial Breakdown. ACS APPLIED MATERIALS & INTERFACES 2024; 16:2120-2139. [PMID: 38170561 DOI: 10.1021/acsami.3c15157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
The process of bonding to dentin is complex and dynamic, greatly impacting the longevity of dental restorations. The tooth/dental material interface is degraded by bacterial acids, matrix metalloproteinases (MMPs), and hydrolysis. As a result, bonded dental restorations face reduced longevity due to adhesive interfacial breakdown, leading to leakage, tooth pain, recurrent caries, and costly restoration replacements. To address this issue, we synthesized and characterized a multifunctional magnetic platform, CHX@SiQuac@Fe3O4@m-SiO2, to provide several beneficial functions. The platform comprises Fe3O4 microparticles and chlorhexidine (CHX) encapsulated within mesoporous silica, which was silanized by an antibacterial quaternary ammonium silane (SiQuac). This platform simultaneously targets bacterial inhibition, stability of the hybrid layer, and enhanced filler infiltration by magnetic motion. Comprehensive experiments include X-ray diffraction, FT-IR, VSM, EDS, N2 adsorption-desorption (BET), transmission electron microscopy, scanning electron microscopy, thermogravimetric analysis, and UV-vis spectroscopy. Then, CHX@SiQuac@Fe3O4@m-SiO2 was incorporated into an experimental adhesive resin for dental bonding restorations, followed by immediate and long-term antibacterial assessment, cytotoxicity evaluation, and mechanical and bonding performance. The results confirmed the multifunctional nature of CHX@SiQuac@Fe3O4@m-SiO2. This work outlined a roadmap for (1) designing and tuning an adhesive formulation containing the new platform CHX@SiQuac@Fe3O4@m-SiO2; (2) assessing microtensile bond strength to dentin using a clinically relevant model of simulated hydrostatic pulpal pressure; and (3) investigating the antibacterial outcome performance of the particles when embedded into the formulated adhesives over time. The results showed that at 4 wt % of CHX@SiQuac@Fe3O4@m-SiO2-doped adhesive under the guided magnetic field, the bond strength increased by 28%. CHX@SiQuac@Fe3O4@m-SiO2 enhanced dentin adhesion in the magnetic guide bonding process without altering adhesive properties or causing cytotoxicity. This finding presents a promising method for strengthening the tooth/dental material interface's stability and extending the bonded restorations' lifespan.
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Affiliation(s)
- Lamia Sami Mokeem
- Ph.D. Program in Biomedical Sciences, University of Maryland School of Dentistry, Baltimore, Maryland 21201, United States
| | - Isadora Martini Garcia
- Ph.D. Program in Biomedical Sciences, University of Maryland School of Dentistry, Baltimore, Maryland 21201, United States
- Division of Cariology and Operative Dentistry, Department of Comprehensive Dentistry, University of Maryland School of Dentistry, Baltimore, Maryland 21201, United States
| | - Abdulrahman A Balhaddad
- Department of Restorative Dental Sciences, College of Dentistry, Imam Abdulrahman Bin Faisal University, Dammam 31441, Saudi Arabia
| | - Yucheng Lan
- Department of Physics and Engineering Physics, Morgan State University, Baltimore, Maryland 21251, United States
| | - Dereje Seifu
- Department of Physics and Engineering Physics, Morgan State University, Baltimore, Maryland 21251, United States
| | - Michael D Weir
- Ph.D. Program in Biomedical Sciences, University of Maryland School of Dentistry, Baltimore, Maryland 21201, United States
- Division of Biomaterials and Tissue Engineering, Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, Maryland 21201, United States
| | - Mary Anne Melo
- Ph.D. Program in Biomedical Sciences, University of Maryland School of Dentistry, Baltimore, Maryland 21201, United States
- Division of Cariology and Operative Dentistry, Department of Comprehensive Dentistry, University of Maryland School of Dentistry, Baltimore, Maryland 21201, United States
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Çakmak G, Akay C, Donmez MB, Mumcu E, Akan HS, Sasany R, Abou-Ayash S, Yilmaz B. Effect of Potassium Aluminum Sulfate Application on the Viability of Fibroblasts on a CAD-CAM Feldspathic Ceramic before and after Thermocycling. MATERIALS 2022; 15:ma15124232. [PMID: 35744291 PMCID: PMC9228813 DOI: 10.3390/ma15124232] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/11/2022] [Accepted: 06/13/2022] [Indexed: 12/10/2022]
Abstract
Potassium aluminum sulfate (alum) is a known adjuvant, which has been used as a mordant in textile industry for color fixation. This material has potential to be incorporated into dentistry for color stability, yet its toxicity first needs to be evaluated. The present study aimed to evaluate the cytotoxic potential of potassium aluminum sulfate (alum) on fibroblasts when applied onto feldspathic ceramic before and after thermocycling. Forty-eight feldspathic ceramic specimens were divided into four groups (FC: no alum application or thermocycling; FCT: thermocycling without alum application; FA: alum application without thermocycling; FAT: alum application and thermocycling) (n = 12). Cell viability was assessed by using a tetrazolium salt 3-[4,5-dimethylthiazol-2-yl]-2,5-diphnyltetrazolium bromide assay at 24 and 72 h, and cell cultures without any ceramic specimens served as control (C). One sample from each material group was further analyzed with energy dispersive X-ray spectroscopy (EDX). Cell viability at different time intervals within each group was analyzed with Friedman tests, while Kruskal−Wallis tests were used to compare the test groups within each time interval. Pairwise comparisons were further resolved by using Wilcoxon tests (a = 0.05). C had lower (p = 0.01) and FA had higher (p = 0.019) cell viability after 72 h. After 24 h, the highest cell viability was observed in C (p ≤ 0.036). After 72 h, the differences between C and FA, C and FAT, FC and FA, and FCT and FAT were nonsignificant (p > 0.05). Cell viability was not affected by alum application or thermocycling at any time interval (p ≥ 0.631). EDX analysis showed an increase in potassium concentration in FA and FAT when compared with FC and FCT. Regardless of the time interval, alum application onto feldspathic ceramic and thermocycling did not influence the cell viability.
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Affiliation(s)
- Gülce Çakmak
- Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, 3012 Bern, Switzerland; (G.Ç.); (S.A.-A.); (B.Y.)
| | - Canan Akay
- Department of Prosthodontics, Faculty of Dentistry, University of Osmangazi, 26040 Eskişehir, Turkey; (C.A.); (E.M.)
- Advanced Material Technologies Application and Research Center, University of Osmangazi, 26040 Eskişehir, Turkey
- Translational Medicine Research and Clinical Center, Eskişehir Osmangazi University, 26040 Eskişehir, Turkey
| | - Mustafa Borga Donmez
- Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, 3012 Bern, Switzerland; (G.Ç.); (S.A.-A.); (B.Y.)
- Department of Prosthodontics, Faculty of Dentistry, Istinye University, 34010 İstanbul, Turkey
- Correspondence:
| | - Emre Mumcu
- Department of Prosthodontics, Faculty of Dentistry, University of Osmangazi, 26040 Eskişehir, Turkey; (C.A.); (E.M.)
- Advanced Material Technologies Application and Research Center, University of Osmangazi, 26040 Eskişehir, Turkey
- Translational Medicine Research and Clinical Center, Eskişehir Osmangazi University, 26040 Eskişehir, Turkey
| | - Handan Sevim Akan
- Department of Biology, Faculty of Science, Hacettepe University, 06800 Ankara, Turkey;
| | | | - Samir Abou-Ayash
- Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, 3012 Bern, Switzerland; (G.Ç.); (S.A.-A.); (B.Y.)
| | - Burak Yilmaz
- Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, 3012 Bern, Switzerland; (G.Ç.); (S.A.-A.); (B.Y.)
- Department of Restorative, Preventive, and Pediatric Dentistry, School of Dental Medicine, University of Bern, 3012 Bern, Switzerland
- Division of Restorative and Prosthetic Dentistry, The Ohio State University, Columbus, OH 43210, USA
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Effects of Color Modifier on Degree of Monomer Conversion, Biaxial Flexural Strength, Surface Microhardness, and Water Sorption/Solubility of Resin Composites. Polymers (Basel) 2021; 13:polym13223902. [PMID: 34833200 PMCID: PMC8622833 DOI: 10.3390/polym13223902] [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: 09/17/2021] [Revised: 11/02/2021] [Accepted: 11/08/2021] [Indexed: 12/05/2022] Open
Abstract
Color modifiers can be mixed with resin composites to mimic the shade of severely discolored tooth. The aim of this study was to assess the effects of a color modifier on the physical and mechanical properties of a resin composite. The composite was mixed with a color modifier at 0 wt% (group 1), 1 wt% (group 2), 2.5 wt% (group 3), or 5 wt% (group 4). The degree of monomer conversion (DC) was examined after light curing for 20 or 40 s. Biaxial flexural strength (BFS)/modulus (BFM), surface microhardness (SH), and water sorption (Wsp)/solubility (Wsl) were also tested. The DC of group 1 was significantly higher than that of groups 3 and 4. The increase in curing time from 20 to 40 s increased the DC by ~10%. The BFS, BFM, Wsp, and Wsl of all the groups were comparable. A negative correlation was detected between the concentration of color modifier and the BFS and DC, while a positive correlation was observed with Wsp. In conclusion, the color modifier reduced the DC of composites, but the conversion was improved by extending the curing time. The increase in color modifier concentration also correlated with a reduction in strength and the increase in the water sorption of the composites.
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Lopes-Rocha L, Ribeiro-Gonçalves L, Henriques B, Özcan M, Tiritan ME, Souza JCM. An integrative review on the toxicity of Bisphenol A (BPA) released from resin composites used in dentistry. J Biomed Mater Res B Appl Biomater 2021; 109:1942-1952. [PMID: 33834604 DOI: 10.1002/jbm.b.34843] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 03/02/2021] [Accepted: 03/28/2021] [Indexed: 11/11/2022]
Abstract
The main aim of this study was to perform an integrative review on the release of bisphenol A (BPA) from resin-matrix composites and potential toxic effects. A bibliographic search was performed on the PubMed platform using the following keywords: "Bisphenol A" OR "BPA" AND "resin composite" OR "composite resin" AND "toxicity" OR "cytotoxicity" OR "release". Inclusion criteria involved in vitro and in vivo studies on the release and toxicity of BPA. Results highlighted the release of BPA from resin-matrix composites due to insufficient polymerization and/or degradation of the polymeric matrix. BPA is part of the organic matrix of resin-matrix composites and may be hydrolysed in human saliva, although studies report that low doses might not be detected by traditional chemical analysis. Studies exposing zebrafish embryos to different concentrations of Bis-GMA, showed 55% mortality at 10 μM Bis-GMA while 30% mortality was recorded at 1 μM Bis-GMA. In patients, a BPA concentration of around 2.09 × 10-2 μg/ml was found in the saliva after placement of lingual orthodontic retainers with resin-matrix composites. Also, the BPA molecule can be swallowed and absorbed by the oral/gastrointestinal mucosa, which might result in systemic toxicity. The degradation of resin-matrix composites and release of BPA in oral environment are dependent on the organic matrix content and on the polymerization method. A increased release of BPA can lead to the absorption into oral and gastrointestinal mucosa with high risks of local and systemic toxicity.
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Affiliation(s)
- Lígia Lopes-Rocha
- Department of Dental Sciences, University Institute of Health Sciences (IUCS), CESPU, Gandra, PRD, Portugal.,Institute for Research and Advanced Training in Health Sciences and Technologies (IINFACTS), CESPU, Gandra PRD, Portugal
| | - Lara Ribeiro-Gonçalves
- Department of Dental Sciences, University Institute of Health Sciences (IUCS), CESPU, Gandra, PRD, Portugal
| | - Bruno Henriques
- Ceramic and Composite Materials Research Group (CERMAT), Dept. of Mechanical Engineering (EMC), Federal University of Santa Catarina (UFSC), Florianópolis, Brazil.,Centre for Microelectromechanical Systems (CMEMS-UMINHO), University of Minho, Campus Azurém, Guimarães, Braga, Portugal
| | - Mutlu Özcan
- Division of Dental Biomaterials, Clinic for Reconstructive Dentistry, Center of Dental Medicine, University of Zürich, Zürich, Switzerland
| | - Maria Elizabeth Tiritan
- Institute for Research and Advanced Training in Health Sciences and Technologies (IINFACTS), CESPU, Gandra PRD, Portugal.,Laboratory of Organic and Pharmaceutical Chemistry (LQOF), Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - Júlio C M Souza
- Department of Dental Sciences, University Institute of Health Sciences (IUCS), CESPU, Gandra, PRD, Portugal.,Centre for Microelectromechanical Systems (CMEMS-UMINHO), University of Minho, Campus Azurém, Guimarães, Braga, Portugal
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Bhadila G, Menon D, Wang X, Vila T, Melo MAS, Montaner S, Arola DD, Weir MD, Sun J, Hockin H K, Xu. Long-term antibacterial activity and cytocompatibility of novel low-shrinkage-stress, remineralizing composites. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2021; 32:886-905. [PMID: 33482702 DOI: 10.1080/09205063.2021.1878805] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A low-shrinkage-stress (LSS), antibacterial and remineralizing nanocomposite was recently developed; however, validation of its long-term antibacterial potency in modulating human salivary-derived biofilm is an unmet need. This study aimed to evaluate the antibacterial effect of the bioactive LSS composite before and after aging in acidic solution for 90 days using a multi-species biofilm model, and to evaluate its cytotoxicity. The LSS composite consisted of urethane dimethacrylate (UDMA) and triethylene glycol divinylbenzyl ether (TEG-DVBE), 3% dimethylaminohexadecyl methacrylate (DMAHDM) and 20% nanoparticles of amorphous calcium phosphate (NACP). Biofilm colony-forming units (CFU), lactic acid production, and confocal laser scanning microscopy (3D biofilm) were evaluated before and after three months of aging. Cytotoxicity was assessed against human gingival fibroblasts (HGF). The new LSS composite presented the lowest biofilm CFU, lactic acid and biofilm biomass, compared to controls (n = 6, p < 0.05). Importantly, the new composite exhibited no significant difference in antibacterial performance before and after 90-day-aging, demonstrating long-term antibacterial activity (p > 0.1). The LSS antibacterial and remineralizing composite presented a low cell viability at original extract that has increased with further dilutions. In conclusion, this study spotlighted that the new bioactive composite not only had a low shrinkage stress, but also down-regulated the growth of oral biofilms, reduced acid production, maintained antibacterial activity after the 90-day-aging, and did not compromise the cytocompatibility.
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Affiliation(s)
- Ghalia Bhadila
- Ph.D. Program in Dental Biomedical Sciences, Biomaterials and Tissue Engineering Division, University of Maryland School of Dentistry, Baltimore, MD, USA.,Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, MD, USA.,Department of Pediatric Dentistry, Faculty of Dentistry, King AbdulAziz University, Jeddah, Saudi Arabia
| | - Deepak Menon
- Department of Oncology and Diagnostic Sciences, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Xiaohong Wang
- Volpe Research Center, American Dental Association Foundation, Frederick, MD, USA
| | - Taissa Vila
- Department of Oncology and Diagnostic Sciences, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Mary Ann S Melo
- Division of Operative Dentistry, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Silvia Montaner
- Department of Oncology and Diagnostic Sciences, University of Maryland School of Dentistry, Baltimore, MD, USA.,Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Dwayne D Arola
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA
| | - Michael D Weir
- Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Jirun Sun
- Volpe Research Center, American Dental Association Foundation, Frederick, MD, USA
| | | | - Xu
- Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, MD, USA.,Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA.,Center for Stem Cell Biology & Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
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Correlation of the mechanical and biological response in light-cured RBCs to receiving a range of radiant exposures: Effect of violet light. J Dent 2020; 105:103568. [PMID: 33385531 DOI: 10.1016/j.jdent.2020.103568] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/11/2020] [Accepted: 12/23/2020] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVE This study correlates the mechanical and biological response of commercially available resin-based composites (RBCs) to clinically relevant light-curing conditions. METHODS Two RBCs (Venus and Venus Pearl; Kulzer) that use different monomer and photo-initiator systems, but have a similar filler volume and shade, were exposed to either just blue light, or violet and blue light from two different LCUs (Translux Wave and Translux 2Wave; Kulzer). Distance and exposure times were adjusted so that both LCUs delivered 5 similar levels of radiant exposures (RE) between 1.5 J/cm²-25 J/cm² in the blue wavelength range. Thus, the violet light was additional light. The top and bottom of 2-mm thick specimens were subjected to a depth-sensing indentation test (Martens hardness/HM, Vickers hardness/HV, indentation modulus/YHU, mechanical work/Wtotal, plastic deformation work/Wplas, creep/Cr). The viability of human gingival fibroblasts was assessed after three days of exposure to RBC eluates. One and multiple-way analysis of variance (ANOVA), the Tukey honestly significant difference (HSD) post-hoc tests (α = 0.05), t-test and a Spearman correlation analysis were used. RESULTS As the RE increased, the mechanical properties increased at a greater rate at the top compared to the bottom of the RBCs. Values measured at the bottom of 2-mm increments approached the values measured at the top only when RE > 25 J/cm² of blue light was delivered. Toxicity decreased with RE and elution cycles and was lower for Venus Pearl. Within one RE level, addition of violet light resulted in significantly improved properties (in 131 out of 150 comparisons, p < 0.05). This effect was stronger for Venus Pearl. There was a good correlation between mechanical and biological parameters. This correlation decreased as the number of eluates increased. CLINICAL SIGNIFICANCE The mechanical and biological response to variation in RE is interrelated. The addition of violet light has a positive effect, particularly at low RE.
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Evaluation of the Bond Strength and Cytotoxicity of Alkasite Restorative Material. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10186175] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cention N (CN; Ivoclar Vivadent, Schaan, Liechtenstein), advertised as an alkasite, is a bioactive bulk-fill resin-based composite (BF-RBC) with alkaline fillers. This study evaluated the resin-dentin micro-tensile bond strength (μTBS) and cytotoxicity of CN. Methods: Flat dentin surfaces were obtained, bonded with a universal adhesive, and randomly distributed into two groups. CN (group I) and a flowable BF-RBC, namely, Tetric N-Flow Bulk Fill, Ivoclar Vivadent, Schaan, Liechtenstein (group II), were used. After thermocycling, bonded samples were sectioned into micro-beams for μTBS evaluation. Resin-based composite (RBC) discs with a thickness of 2 and 4 mm were tested on human gingival fibroblast cells (HGFCs). Cytotoxicity was assessed by cell viability and growth using AlamarBlue® (Biosource, Camarillo, CA, USA) over a seven-day period. Independent t-test was utilized to statistically analyze μTBS data, while one- and two-way analysis of variance (ANOVA) and Tukey’s post-hoc tests were utilized to analyze the cell viability data. Results: There was no statistically significant difference (p > 0.05) in the μTBS between the flowable BF-RBC and CN. For both materials, the HGFCs were viable, with constant growing over the seven-day period. Conclusion: CN provided a resin-dentin μTBS that was comparable to that provided by the flowable BF-RBC. Both materials showed acceptable cytotoxicity over the seven-day period at a thickness of both 2 and 4 mm.
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In vitro and in silico evaluations of resin-based dental restorative material toxicity. Clin Oral Investig 2019; 24:2691-2700. [PMID: 31713743 DOI: 10.1007/s00784-019-03131-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 10/22/2019] [Indexed: 12/20/2022]
Abstract
OBJECTIVES This study aims to evaluate the cytocompatibility of three provisional restoration materials and predict neurotoxic potential of their monomers. These materials are Tab 2000® (methyl methacrylate based), ProTemp 4™ (bis-acrylic based) and Structur 3® (urethane dimethacrylate based). MATERIALS AND METHODS Resin samples were incubated in a cell culture medium and the cytotoxic effects of these extracts were studied in 3T3 fibroblast cells through MTT and crystal violet assays as well as ROS assessment. The presence of relevant leached monomers was determined by HPLC. Additionally, the blood-brain barrier (BBB) permeability to these resin-based monomers was predicted using ACD/Labs algorithms model. RESULTS Cell survival rates were compared with the resin extracts, and Structur 3® was statistically significant different from the others (p < 0.001) at all-time incubation periods. All materials induced a dose-dependent loss of cell viability; however, only Structur 3 extracts were cytotoxic against 3T3 fibroblasts. The highest cytotoxic effect (77%, p < 0.001) was observed at 24 h incubation period, which may be associated with the presence of urethane dimethacrylate (UDMA) leached monomers. Furthermore, the computational model showed that most monomers under study are expectedly capable of crossing the BBB. CONCLUSIONS Our results showed that Structur 3® is not cytocompatible with our cell model and UDMA is a potential neurotoxic compound. CLINICAL RELEVANCE These results indicate that only ProTemp 4™ and Tab 2000® are safe for provisional restorations.
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Yi J, Dai Q, Weir MD, Melo MA, Lynch CD, Oates TW, Zhang K, Zhao Z, Xu HH. A nano-CaF2-containing orthodontic cement with antibacterial and remineralization capabilities to combat enamel white spot lesions. J Dent 2019; 89:103172. [DOI: 10.1016/j.jdent.2019.07.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 07/16/2019] [Accepted: 07/17/2019] [Indexed: 12/19/2022] Open
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12
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Zhou X, Huang X, Li M, Peng X, Wang S, Zhou X, Cheng L. Development and status of resin composite as dental restorative materials. J Appl Polym Sci 2019. [DOI: 10.1002/app.48180] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Xinxuan Zhou
- State Key Laboratory of Oral DiseasesSichuan University Chengdu 610041 Sichuan China
- National Clinical Research Center for Oral DiseasesSichuan University Chengdu 610041 Sichuan China
| | - Xiaoyu Huang
- State Key Laboratory of Oral DiseasesSichuan University Chengdu 610041 Sichuan China
- Department of Operative Dentistry and Endodontics, West China Hospital of StomatologySichuan University Chengdu 610041 Sichuan China
- National Clinical Research Center for Oral DiseasesSichuan University Chengdu 610041 Sichuan China
| | - Mingyun Li
- State Key Laboratory of Oral DiseasesSichuan University Chengdu 610041 Sichuan China
- National Clinical Research Center for Oral DiseasesSichuan University Chengdu 610041 Sichuan China
| | - Xian Peng
- State Key Laboratory of Oral DiseasesSichuan University Chengdu 610041 Sichuan China
- National Clinical Research Center for Oral DiseasesSichuan University Chengdu 610041 Sichuan China
| | - Suping Wang
- Department of Operative Dentistry and Endodontics & Stomatology CenterThe First Affiliated Hospital of Zhengzhou University Zhengzhou 540052 Henan China
| | - Xuedong Zhou
- State Key Laboratory of Oral DiseasesSichuan University Chengdu 610041 Sichuan China
- Department of Operative Dentistry and Endodontics, West China Hospital of StomatologySichuan University Chengdu 610041 Sichuan China
- National Clinical Research Center for Oral DiseasesSichuan University Chengdu 610041 Sichuan China
| | - Lei Cheng
- State Key Laboratory of Oral DiseasesSichuan University Chengdu 610041 Sichuan China
- Department of Operative Dentistry and Endodontics, West China Hospital of StomatologySichuan University Chengdu 610041 Sichuan China
- National Clinical Research Center for Oral DiseasesSichuan University Chengdu 610041 Sichuan China
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Liu B, Gan X, Zhao Y, Chen J, Yu H, Gao J, Yu H. TEGDMA releasing in resin composites with different filler contents and its correlation with mitochondrial mediated cytotoxicity in human gingival fibroblasts. J Biomed Mater Res A 2019; 107:1132-1142. [PMID: 30597721 DOI: 10.1002/jbm.a.36600] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 11/27/2018] [Accepted: 12/26/2018] [Indexed: 02/05/2023]
Abstract
Compositions of resin composite exhibit cytotoxicity, especially Triethylene-glycol-dimethacrylate (TEGDMA), yet the underlying mechanisms and its relationship with filler content are poorly understood. Here, specimens of five composites (VITA LC, VITA ZETA, Z350, Filtek P60, and AP-X), containing different filler size and weight, were immersed into culture medium for 72 h. After TEGDMA quantification, the resin composite eluates were used to incubate HGFs. Cellular viability was evaluated. Total reactive oxygen species (ROS) and mitochondrial ROS were detected to assess oxidative stress. Adenosine triphosphate and cytochrome c oxidase (CcO) activity, mitochondrial membrane potential and morphology, mitochondrial biogenesis regulators were analyzed to evaluate mitochondrial functions. Results showed that TEGDMA release negatively correlated to filler size and weight of tested composites. Although cell viability reduction was not significant, total and mitochondrial ROS production showed a positive relationship with the amount of TEGDMA in composite eluates. Furthermore, the expression of mitochondrial biogenesis markers and mitochondrial fusion protein, were markedly elevated in TEGDMA rich eluates, especially in VITA-LC group, shown as elongated mitochondrial morphology and aberrant mitochondrial functions. Overall, TEGDMA could elute easier from those resin composites with less filler content and cause oxidative stress in HGFs via mitochondria dysregulation. These data can be instructive to optimize the synthesis of resin composites from the perspective of biocompatibility. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1132-1142, 2019.
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Affiliation(s)
- Beilei Liu
- State Key Laboratory of Oral Disease, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, PR China
| | - Xueqi Gan
- State Key Laboratory of Oral Disease, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, PR China
| | - Yuwei Zhao
- State Key Laboratory of Oral Disease, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, PR China
| | - Junsheng Chen
- State Key Laboratory of Oral Disease, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, PR China
| | - Hongdou Yu
- State Key Laboratory of Oral Disease, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, PR China
| | - Jing Gao
- State Key Laboratory of Oral Disease, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, PR China
| | - Haiyang Yu
- State Key Laboratory of Oral Disease, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, PR China
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Pflaum T, Kranz S, Montag R, Güntsch A, Völpel A, Mills R, Jandt K, Sigusch B. Clinical long-term success of contemporary nano-filled resin composites in class I and II restorations cured by LED or halogen light. Clin Oral Investig 2017; 22:1651-1662. [PMID: 29080928 DOI: 10.1007/s00784-017-2226-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 09/27/2017] [Indexed: 11/30/2022]
Abstract
OBJECTIVES The use of LED light-curing units (LED LCUs) for polymerising resin-based composite restorations has become widespread throughout dentistry. Unfortunately, there is a paucity of clinical longitudinal studies that evaluate the comparative efficacy of LED-based polymerisation in direct posterior composite restorations. The aim of the present study was to investigate the performance of class I and II resin composite restorations for two successful composite restorative materials cured with LED versus halogen LCUs. METHODS One hundred restorations were placed using the nano-filled composites Grandio® or Filtek™ Supremé. The following test groups were established: LED-Grandio® n = 23 (LG), LED-Filtek™ Supremé n = 21 (LS). As controls were used: Halogen-Grandio® n = 28 (HG), Halogen-Filtek™ Supremé n = 28 (HS). All restorations were evaluated according to the clinical criteria of the CPM index (C-criteria) at baseline and after 6, 12 and 36 months. RESULTS After 12 and 36 months, there were no significant differences between restorations polymerised with LED or halogen light. At the end of the study, 97% of the restorations showed sufficient results regardless of the employed LCU or composite. Globally, after 36 months, 56% of all restorations were assessed with code 0 (excellent) and 41% with code 1 (acceptable). In detail, excellent results (code 0) among the criteria surface quality; marginal integrity and marginal discoloration were assigned in 72, 70 and 69%. CONCLUSIONS For the current limitations in the clinical trial design, the results showed that LED-polymerisation is appropriate to ensure clinical success of direct posterior resin composite restorations in a range of 3 years. CLINICAL SIGNIFICANCE The choice of LCU has no significant influence on the clinical performance of posterior direct resin composite restorations within 3 years of wear.
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Affiliation(s)
- Torsten Pflaum
- Policlinic of Conservative Dentistry and Periodontology, Jena University Hospital, An der alten Post 4, 07743, Jena, Germany.
| | - Stefan Kranz
- Policlinic of Conservative Dentistry and Periodontology, Jena University Hospital, An der alten Post 4, 07743, Jena, Germany
| | - Regina Montag
- Policlinic of Conservative Dentistry and Periodontology, Jena University Hospital, An der alten Post 4, 07743, Jena, Germany
| | - Arndt Güntsch
- Department of Surgical Sciences, Marquette University, Milwaukee, USA
| | - Andrea Völpel
- Policlinic of Conservative Dentistry and Periodontology, Jena University Hospital, An der alten Post 4, 07743, Jena, Germany
| | - Robin Mills
- School of Oral and Dental Sciences, University of Bristol, Bristol, BS1 2LY, UK
| | - Klaus Jandt
- Otto Schott Institute for Materials Research, 07743, Jena, Germany
| | - Bernd Sigusch
- Policlinic of Conservative Dentistry and Periodontology, Jena University Hospital, An der alten Post 4, 07743, Jena, Germany
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Yang Y, Reichl FX, Shi J, He X, Hickel R, Högg C. Cytotoxicity and DNA double-strand breaks in human gingival fibroblasts exposed to eluates of dental composites. Dent Mater 2017; 34:201-208. [PMID: 29042079 DOI: 10.1016/j.dental.2017.10.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 08/07/2017] [Accepted: 10/02/2017] [Indexed: 10/18/2022]
Abstract
OBJECTIVE Previously, single composite components were used to study cytotoxicity and induction of DNA double-strand breaks (DNA-DSBs) of dental composite resins. In the present study, cytotoxicity and induction of DNA-DSBs in human gingival fibroblasts (HGFs) were investigated with dental composite eluates consisting of multiple components. The eluates were qualified and quantified. METHODS The composites Esthet.X® HD, Venus®, X-tra fil®, CLEARFIL™ AP-X, Admira® Fusion and QuiXfil® were polymerized and immersed into Dulbecco's modified Eagle's medium (DMEM) for 72h. Subsequently, HGFs were incubated with the corresponding composite eluates. The cell viability of HGFs was obtained from an XTT assay. DNA-DSBs were determined using a γ-H2AX assay. The qualification and quantification of eluates were performed by gas chromatography/mass spectrometry (GC/MS). RESULTS HGFs exposed to the eluates of all investigated composites showed no significant loss of cell viability, compared to negative control. Significant DNA-DSBs induction could be found in HGFs exposed to the eluates of Esthet.X® HD (0.43±0.05 foci/cell) and Venus® (0.39±0.04 foci/cell), compared to control (0.22±0.03 foci/cell). A total of 12 substances were detected from the investigated composite eluates. Five of them were methacrylates: tetraethyleneglycol dimethacrylate (TEGDMA), 2-hydroxyethyl methacrylate (HEMA), hydroxypropyl methacrylate (HPMA), ethyleneglycol dimethacrylate (EGDMA) and trimethylolpropane trimethacrylate (TMPTMA). The highest concentration of HEMA (110.5μM), HPMA (86.08μM) and TMPTMA (4.50μM) was detected in the eluates of QuiXfil®. The highest concentration of TEGDMA was 1080μM in Venus® eluates and the highest concentration of EGDMA was 3.18μM in Esthet.X® HD eluates. SIGNIFICANCE Significant DNA-DSBs induction can be found in HGFs exposed to the eluates of Esthet.X® HD and Venus®. The interactive effects among released (co)monomers and additives may influence the cytotoxicity and induction of DNA-DSBs, compared to exposure with single composite component.
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Affiliation(s)
- Yang Yang
- Department of Conservative Dentistry and Periodontology, University Hospital, LMU Munich, Germany; Walther-Straub-Institute of Pharmacology and Toxicology, Ludwig-Maximilians-University of Munich, Nußbaumstr. 26, 80336 Munich, Germany
| | - Franz-Xaver Reichl
- Department of Conservative Dentistry and Periodontology, University Hospital, LMU Munich, Germany; Walther-Straub-Institute of Pharmacology and Toxicology, Ludwig-Maximilians-University of Munich, Nußbaumstr. 26, 80336 Munich, Germany
| | - Jianwei Shi
- Department of Orthodontics, Ludwig-Maximilians-University of Munich, Goethestr. 70, 80336 Munich, Germany
| | - Xiuli He
- Department of Conservative Dentistry and Periodontology, University Hospital, LMU Munich, Germany; Walther-Straub-Institute of Pharmacology and Toxicology, Ludwig-Maximilians-University of Munich, Nußbaumstr. 26, 80336 Munich, Germany
| | - Reinhard Hickel
- Department of Conservative Dentistry and Periodontology, University Hospital, LMU Munich, Germany
| | - Christof Högg
- Department of Conservative Dentistry and Periodontology, University Hospital, LMU Munich, Germany; Walther-Straub-Institute of Pharmacology and Toxicology, Ludwig-Maximilians-University of Munich, Nußbaumstr. 26, 80336 Munich, Germany.
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Degrazia FW, Leitune VCB, Samuel SMW, Collares FM. Boron nitride nanotubes as novel fillers for improving the properties of dental adhesives. J Dent 2017; 62:85-90. [DOI: 10.1016/j.jdent.2017.05.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 05/16/2017] [Accepted: 05/17/2017] [Indexed: 11/24/2022] Open
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Attik N, Hallay F, Bois L, Brioude A, Grosgogeat B, Colon P. Mesoporous silica fillers and resin composition effect on dental composites cytocompatibility. Dent Mater 2017; 33:166-174. [DOI: 10.1016/j.dental.2016.11.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 11/04/2016] [Accepted: 11/17/2016] [Indexed: 01/20/2023]
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Study of energy transfer by different light curing units into a class III restoration as a function of tilt angle and distance, using a MARC Patient Simulator (PS). Dent Mater 2016; 32:676-86. [DOI: 10.1016/j.dental.2016.02.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 02/23/2016] [Accepted: 02/24/2016] [Indexed: 11/24/2022]
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AlQahtani MQ, Michaud PL, Sullivan B, Labrie D, AlShaafi MM, Price RB. Effect of High Irradiance on Depth of Cure of a Conventional and a Bulk Fill Resin-based Composite. Oper Dent 2015; 40:662-72. [PMID: 26237638 DOI: 10.2341/14-244-l] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVES This study evaluated the effect of using three commercial light curing units (LCUs) delivering a range of irradiance values, but delivering similar radiant exposures on the depth of cure of two different resin-based composites (RBCs). METHODS A conventional hybrid RBC (Z100 shade A2, 3M ESPE) or a bulk fill RBC (Tetric EvoCeram Bulk Fill shade IVA, Ivoclar Vivadent) was packed into a 10-mm deep semicircular metal mold with a 2-mm internal radius. The RBC was exposed to light from a plasma-arc-curing (PAC) light (Sapphire Plus, DenMat) for five seconds, a quartz-tungsten-halogen (QTH) light (Optilux 501, Kerr) for 40 seconds, or a light-emitting-diode (LED) light (S10, 3M ESPE) for 20 seconds and 40 seconds (control). The Knoop microhardness was then measured as soon as possible at the top surface and at three points every 0.5 mm down from the surface. For each RBC, a repeated measures analysis of variance (ANOVA) model was used to predict the Knoop hardness in a manner analogous to a standard regression model. This predicted value was used to determine at what depth the RBC reached 80% of the mean hardness achieved at the top surface with any light. RESULTS The PAC light delivered an irradiance and radiant exposure of 7328 mW/cm(2) and 36.6 J/cm(2), respectively, to the RBCs; the QTH light delivered 936 mW/cm(2) and 37.4 J/cm(2) and in 20 seconds the LED light delivered 1825 mW/cm(2) and 36.5 J/cm(2). In 40 seconds, the control LED light delivered a radiant exposure of 73.0 J/cm(2). For Z100, using 80% of the maximum hardness at the top surface as the criteria for adequate curing, all light exposure conditions achieved the 2.0-mm depth of cure claimed by the manufacturer. The LED light used for 40 seconds achieved the greatest depth of cure (5.0 mm), and the PAC light used for five seconds, the least (2.5 mm). Tetric EvoCeram Bulk Fill achieved a 3.5-mm depth of cure when the broad-spectrum QTH light was used for 40 seconds delivering 37.4 J/cm(2). It required a 40-second exposure time with the narrow-spectrum LED, delivering approximately 73 J/cm(2) to reach a depth of cure of 4 mm. CONCLUSIONS When delivering a similar radiant exposure of 37 J/cm(2), the QTH (40 seconds) and LED (20 seconds) units achieved a greater depth of cure than the PAC (five seconds) light. For both resins, the greatest depth of cure was achieved when the LED light was used for 40 seconds delivering 73 J/cm(2) (p<0.05).
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Kwon HJ, Oh YJ, Jang JH, Park JE, Hwang KS, Park YD. The effect of polymerization conditions on the amounts of unreacted monomer and bisphenol A in dental composite resins. Dent Mater J 2015; 34:327-35. [PMID: 25904171 DOI: 10.4012/dmj.2014-230] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The aim of this study was to analyze the unreacted monomers of four commonly used composite resins, which were released after curing with different polymerization conditions. Four composite resins, consisting of two hybrid types and two flowable types from two manufacturers, were photopolymerized using different curing times and curing distances. After polymerization, samples were extracted for analysis at different time points up to 24 h. Released monomers were analyzed by reversed-phase liquid chromatography at UV 210 nm. Longer curing times and shorter curing distances resulted in higher polymerization rates and decreased release of TEGDMA and UDMA, but changes in curing time and distance had no significant effect on Bis-GMA. Release of BPA increased with increase in curing time or decrease in curing distance, in contrast to the results of TEGDMA and UDMA. Polymerization conditions need to be differently applied according to both monomer and resin types.
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Affiliation(s)
- Ha-Jeong Kwon
- Department of Preventive and Social Dentistry, Kyung Hee University
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Elias ST, Santos AFD, Garcia FCP, Pereira PNR, Hilgert LA, Fonseca-Bazzo YM, Guerra ENS, Ribeiro APD. Cytotoxicity of universal, self-etching and etch-and-rinse adhesive systems according to the polymerization time. Braz Dent J 2015; 26:160-8. [PMID: 25831108 DOI: 10.1590/0103-6440201300294] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 01/13/2015] [Indexed: 11/22/2022] Open
Abstract
This in vitro study evaluated in fibroblast cultures the direct cytotoxicity of universal, self-etching and etch-and-rinse adhesive systems according to the polymerization time. Paper discs were impregnated with adhesives and light-cured (10, 20 or 40 s). The discs were then immersed in culture medium to obtain the eluates for the experimental groups (A1-Single Bond 2; A2-Scotchbond Multi-purpose; A3-Clearfil SE Bond; A4 Scotchbond Universal). As a negative control, paper discs were immersed in culture medium only. After 24 h or 7 days, the eluate obtained was applied on fibroblast culture. Cell viability, cell morphology, membrane damage and the presence of residual monomers were evaluated by MTT assay, SEM, flow cytometry and high-performance liquid chromatography (HPLC), respectively. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests (=0.05). All adhesive systems significantly reduced 33-51% cell metabolism when compared to the negative control, regardless of polymerization time, storage period and adhesive system. Moreover, the adhesives caused intense morphological alterations and cell membrane damage. Toxicity was directly related to the presence of residual monomers in the eluates. Residual monomers and additional components are capable of reducing mitochondrial activity, causing morphological alterations and disruption of the cell membrane in fibroblasts, regardless of the polymerization time. This study highlights that despite the more complex composition of the universal adhesive system, its biological response was not more toxic when compared with other systems, even when the shortest polymerization time was tested in cell culture.
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Affiliation(s)
- Silvia T Elias
- Laboratory of Oral Histopathology, Department of Dentistry, School of Health Sciences, UNB - University of Brasilia, Brasilia, DF, Brazil
| | - Andressa F Dos Santos
- Department of Dentistry, School of Health Sciences, UNB - University of Brasilia, Brasilia, DF, Brazil
| | - Fernanda C P Garcia
- Department of Dentistry, School of Health Sciences, UNB - University of Brasilia, Brasilia, DF, Brazil
| | - Patrícia N R Pereira
- Department of Dentistry, School of Health Sciences, UNB - University of Brasilia, Brasilia, DF, Brazil
| | - Leandro A Hilgert
- Department of Dentistry, School of Health Sciences, UNB - University of Brasilia, Brasilia, DF, Brazil
| | - Yris M Fonseca-Bazzo
- Department of Pharmaceutical Sciences, School of Health Sciences, UNB - University of Brasilia, Brasilia, DF, Brazil
| | - Eliete N S Guerra
- Laboratory of Oral Histopathology, Department of Dentistry, School of Health Sciences, UNB - University of Brasilia, Brasilia, DF, Brazil
| | - Ana Paula Dias Ribeiro
- Department of Dentistry, School of Health Sciences, UNB - University of Brasilia, Brasilia, DF, Brazil
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Selig D, Haenel T, Hausnerová B, Moeginger B, Labrie D, Sullivan B, Price RBT. Examining exposure reciprocity in a resin based composite using high irradiance levels and real-time degree of conversion values. Dent Mater 2015; 31:583-93. [PMID: 25804190 DOI: 10.1016/j.dental.2015.02.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 12/10/2014] [Accepted: 02/16/2015] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Exposure reciprocity suggests that, as long as the same radiant exposure is delivered, different combinations of irradiance and exposure time will achieve the same degree of resin polymerization. This study examined the validity of exposure reciprocity using real time degree of conversion results from one commercial flowable dental resin. Additionally a new fitting function to describe the polymerization kinetics is proposed. METHODS A Plasma Arc Light Curing Unit (LCU) was used to deliver 0.75, 1.2, 1.5, 3.7 or 7.5 W/cm(2) to 2mm thick samples of Tetric EvoFlow (Ivoclar Vivadent). The irradiances and radiant exposures received by the resin were determined using an integrating sphere connected to a fiber-optic spectrometer. The degree of conversion (DC) was recorded at a rate of 8.5 measurements a second at the bottom of the resin using attenuated total reflectance Fourier Transform mid-infrared spectroscopy (FT-MIR). Five specimens were exposed at each irradiance level. The DC reached after 170s and after 5, 10 and 15 J/cm(2) had been delivered was compared using analysis of variance and Fisher's PLSD post hoc multiple comparison tests (alpha=0.05). RESULTS The same DC values were not reached after the same radiant exposures of 5, 10 and 15 J/cm(2) had been delivered at an irradiance of 3.7 and 7.5 W/cm(2). Thus exposure reciprocity was not supported for Tetric EvoFlow (p<0.05). SIGNIFICANCE For Tetric EvoFlow, there was no significant difference in the DC when 5, 10 and 15J/cm(2) were delivered at irradiance levels of 0.75, 1.2 and 1.5 W/cm(2). The optimum combination of irradiance and exposure time for this commercial dental resin may be close to 1.5 W/cm(2) for 12s.
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Affiliation(s)
- Daniela Selig
- Dalhousie University, Department of Dental Clinical Sciences, Faculty of Dentistry, Halifax, Canada; Bonn-Rhein-Sieg University of Applied Sciences, Department of Natural Sciences, Rheinbach, Germany; FH Aachen University of Applied Sciences, Department of Natural Sciences, Jülich, Germany
| | - Thomas Haenel
- Dalhousie University, Department of Dental Clinical Sciences, Faculty of Dentistry, Halifax, Canada; Bonn-Rhein-Sieg University of Applied Sciences, Department of Natural Sciences, Rheinbach, Germany; Tomas Bata University in Zlin, Faculty of Technology, Department of Production Engineering, Zlin, Czech Republic; Tomas Bata University in Zlin, University Institute, Centre of Polymer Systems, Zlin, Czech Republic
| | - Berenika Hausnerová
- Tomas Bata University in Zlin, Faculty of Technology, Department of Production Engineering, Zlin, Czech Republic; Tomas Bata University in Zlin, University Institute, Centre of Polymer Systems, Zlin, Czech Republic
| | - Bernhard Moeginger
- Bonn-Rhein-Sieg University of Applied Sciences, Department of Natural Sciences, Rheinbach, Germany
| | - Daniel Labrie
- Dalhousie University, Department of Physics and Atmospheric Sciences, Halifax, Canada
| | - Braden Sullivan
- Dalhousie University, Department of Dental Clinical Sciences, Faculty of Dentistry, Halifax, Canada
| | - Richard B T Price
- Dalhousie University, Department of Dental Clinical Sciences, Faculty of Dentistry, Halifax, Canada.
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Salehi S, Gwinner F, Mitchell JC, Pfeifer C, Ferracane JL. Cytotoxicity of resin composites containing bioactive glass fillers. Dent Mater 2015; 31:195-203. [PMID: 25564110 DOI: 10.1016/j.dental.2014.12.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 08/18/2014] [Accepted: 12/05/2014] [Indexed: 01/28/2023]
Abstract
OBJECTIVE To determine the in vitro cytotoxicity of dental composites containing bioactive glass fillers. METHODS Dental composites (50:50 Bis-GMA/TEGDMA resin: 72.5wt% filler, 67.5%Sr-glass and 5% OX50) containing different concentrations (0, 5, 10 and 15wt%) of two sol-gel bioactive glasses, BAG65 (65mole% SiO2, 31mole% CaO, 4mole% P2O5) and BAG61 (3mole% F added) were evaluated for cytotoxicity using Alamar Blue assay. First, composite extracts were obtained from 7 day incubations of composites in cell culture medium at 37°C. Undifferentiated pulp cells (OD-21) were exposed to dilutions of the original extracts for 3, 5, and 7 days. Then freshly cured composite disks were incubated with OD-21 cells (n=5) for 2 days. Subsequently, fresh composite disks were incubated in culture medium at 37°C for 7 days, and then the extracted disks were incubated with OD-21 cells for 2 days. Finally, fresh composites disks were light cured for 3, 5, and 20s and incubated with OD-21 cells (n=5) for 1, 3, 5, and 7 days. To verify that the three different curing modes produced different levels of degree of conversion (DC), the DC of each composite was determined by FTIR. Groups (n=5) were compared with ANOVA/Tukey's (α≤0.05). RESULTS Extracts from all composites significantly reduced cell viability until a dilution of 1:8 or lower, where the extract became equal to the control. All freshly-cured composites showed significantly reduced cell viability at two days. However, no reduction in cell viability was observed for any composite that had been previously soaked in media before exposure to the cells. Composites with reduced DC (3s vs. 20s cure), as verified by FTIR, showed significantly reduced cell viability. SIGNIFICANCE The results show that the composites, independent of composition, had equivalent potency in terms of reducing the viability of the cells in culture. Soaking the composites for 7 days before exposing them to the cells suggested that the "toxic" components had been extracted and the materials were no longer cytotoxic. The results demonstrate that the cytotoxicity of composites with and without BAG must predominantly be attributed to the release of residual monomers, and not to the presence of the BAG.
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Affiliation(s)
- Satin Salehi
- Division of Biomaterials and Biomechanics, Department of Restorative, School of Dentistry, Oregon Health Science University, Portland, OR, USA.
| | - Fernanda Gwinner
- Division of Biomaterials and Biomechanics, Department of Restorative, School of Dentistry, Oregon Health Science University, Portland, OR, USA
| | | | - Carmem Pfeifer
- Division of Biomaterials and Biomechanics, Department of Restorative, School of Dentistry, Oregon Health Science University, Portland, OR, USA
| | - Jack L Ferracane
- Division of Biomaterials and Biomechanics, Department of Restorative, School of Dentistry, Oregon Health Science University, Portland, OR, USA
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Toro DA, Villegas CA, Pavicic MF, Fritz MA, Ehrenfeld IP. Evaluation in vitro of cytotoxicity of dentinal desensitizing on human gingival fibroblasts. JOURNAL OF ORAL RESEARCH 2014. [DOI: 10.17126/joralres.2015.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Attik GN, Gritsch K, Colon P, Grosgogeat B. Confocal time lapse imaging as an efficient method for the cytocompatibility evaluation of dental composites. J Vis Exp 2014:e51949. [PMID: 25406737 PMCID: PMC4353434 DOI: 10.3791/51949] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
It is generally accepted that in vitro cell material interaction is a useful criterion in the evaluation of dental material biocompatibility. The objective of this study was to use 3D CLSM time lapse confocal imaging to assess the in vitro biocompatibility of dental composites. This method provides an accurate and sensitive indication of viable cell rate in contact with dental composite extracts. The ELS extra low shrinkage, a dental composite used for direct restoration, has been taken as example. In vitro assessment was performed on cultured primary human gingival fibroblast cells using Live/Dead staining. Images were obtained with the FV10i confocal biological inverted system and analyzed with the FV10-ASW 3.1 Software. Image analysis showed a very slight cytotoxicity in the presence of the tested composite after 5 hours of time lapse. A slight decrease of cell viability was shown in contact with the tested composite extracts compared to control cells. The findings highlighted the use of 3D CLSM time lapse imaging as a sensitive method to qualitatively and quantitatively evaluate the biocompatibility behavior of dental composites.
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Affiliation(s)
- Ghania Nina Attik
- Laboratoire des Multimatériaux et Interfaces, UMR CNRS 5615, Université Lyon1;
| | - Kerstin Gritsch
- Laboratoire des Multimatériaux et Interfaces, UMR CNRS 5615, Université Lyon1; UFR d'Odontologie, Université Lyon1; Service de Consultations et de Traitements Dentaires, Hospices Civils de Lyon
| | - Pierre Colon
- Laboratoire des Multimatériaux et Interfaces, UMR CNRS 5615, Université Lyon1; UFR d'Odontologie, Université Paris Diderot; Service d'Odontologie, APHP, Hôpital Rothschild
| | - Brigitte Grosgogeat
- Laboratoire des Multimatériaux et Interfaces, UMR CNRS 5615, Université Lyon1; UFR d'Odontologie, Université Lyon1; Service de Consultations et de Traitements Dentaires, Hospices Civils de Lyon
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Catelan A, Mainardi MDCAJ, Soares GP, de Lima AF, Ambrosano GMB, Lima DANL, Marchi GM, Aguiar FHB. Effect of light curing protocol on degree of conversion of composites. Acta Odontol Scand 2014; 72:898-902. [PMID: 24856190 DOI: 10.3109/00016357.2014.920108] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
OBJECTIVE To evaluate the degree of conversion (DC) of two light-cured composites with different protocols of light curing. MATERIALS AND METHODS One hundred and ninety two specimens (n = 8) were prepared (5 mm × 2 mm) according to experimental groups: two composite resins (Filtek Supreme and four seasons); three light curing protocols [20 s with the tip of the light curing unit (LCU) device touching composite surface (C); 20 s with the tip of the LCU at 8 mm distant from composite surface (D); and tip of the LCU at 8 mm distant from composite surface and polymerization time required to obtain a radiant exposure of 16 J/cm(2) (DS)]. Four LCUs (Bluephase 16i, Ultralume LED 5, XL 3000 and Optilux 501C) were used. DC of the bottom and top surface of specimens were measured using a FTIR spectrometer. Data were statistically analyzed by 3-way split splot ANOVA and Tukey's test (alpha = 0.05). RESULTS The results showed that DC of the top surface was higher than the bottom at all experimental conditions (p < 0.0001). Overall, the curing at 8 mm of distance did not affect conversion rate on the top surface (p > 0.05), but bottom surfaces showed DC reduction (p < 0.05). The highest monomer conversion values were observed for C and DS situations. CONCLUSION The distance between the LCU and material surface and radiant exposure can affect the DC. Polymerization at distance should be performed with curing units with higher light power and/or extended exposure time.
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Dawson VS, Amjad S, Fransson H. Endodontic complications in teeth with vital pulps restored with composite resins: a systematic review. Int Endod J 2014; 48:627-38. [DOI: 10.1111/iej.12364] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 07/31/2014] [Indexed: 11/28/2022]
Affiliation(s)
- V. S. Dawson
- Department of Endodontics; Faculty of Odontology; Malmö University; Malmö Sweden
| | - S. Amjad
- Department of Endodontics; Faculty of Odontology; Malmö University; Malmö Sweden
| | - H. Fransson
- Department of Endodontics; Faculty of Odontology; Malmö University; Malmö Sweden
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Influence of irradiation time on subsurface degree of conversion and microhardness of high-viscosity bulk-fill resin composites. Clin Oral Investig 2014; 19:831-40. [DOI: 10.1007/s00784-014-1302-6] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 08/07/2014] [Indexed: 10/24/2022]
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Dietz W, Montag R, Kraft U, Walther M, Sigusch BW, Gaengler P. Longitudinal micromorphological 15-year results of posterior composite restorations using three-dimensional scanning electron microscopy. J Dent 2014; 42:959-69. [DOI: 10.1016/j.jdent.2014.04.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 04/25/2014] [Accepted: 04/26/2014] [Indexed: 10/25/2022] Open
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Shafiei F, Tavangar MS, Razmkhah M, Attar A, Alavi AA. Cytotoxic effect of silorane and methacrylate based composites on the human dental pulp stem cells and fibroblasts. Med Oral Patol Oral Cir Bucal 2014; 19:e350-8. [PMID: 24608214 PMCID: PMC4119310 DOI: 10.4317/medoral.19340] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2013] [Accepted: 09/26/2013] [Indexed: 11/21/2022] Open
Abstract
Objectives: The aim of this study was to compare the cytotoxic effect of a methacrylate-based and a silorane-based composite on the human dental pulp stem cells (DPSCs) versus human dental pulp fibroblasts (DPFs).
Study Design: Samples of the Filtek Z250 and P90 were polymerized and immersed in the culture medium to obtain extracts after incubation for one, seven and 14 days. Magnetic cell sorting based on the CD146 expression was performed to purify DPSCs and DPFs. After incubation of both cells with the extracts, cytotoxicity was determined using the MTT test.
Results: For the extracts of first and seventh day, both composites showed significantly lower cytotoxicity on DPSCs than DPFs (p=0.003). In addition, there was a significant difference in the time-group interaction of both materials indicating different cytotoxic behaviours (p=0.014). In contrast to Z250, exposure to the 14th day extract of P90 resulted in higher cell viability compared to that of day seven.
Conclusions: DPSCs are less susceptible to the cytotoxic effect of the composites than DPFs. Compared to Z250, the cytotoxic effect of silorane-based composite decreases as the time passes on. This difference should be considered, particularly in deep cavities, in order to preserve the regenerative capacity of the pulp.
Key words:Composite resins, Dental pulp, Mesenchymal Stromal Cells, Silorane, Toxicology.
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Affiliation(s)
- Fereshteh Shafiei
- Department of Operative Dentistry, Dental Faculty, Ghasrdasht Street, 71345-1836, Shiraz, Iran,
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Attik GN, Pradelle-Plasse N, Campos D, Colon P, Grosgogeat B. Toxicity evaluation of two dental composites: three-dimensional confocal laser scanning microscopy time-lapse imaging of cell behavior. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2013; 19:596-607. [PMID: 23635466 DOI: 10.1017/s1431927613000433] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The purpose of this study was to investigate the in vitro biocompatibility of two dental composites (namely A and B) with similar chemical composition used for direct restoration using three-dimensional confocal laser scanning microscopy (CLSM) time-lapse imaging. Time-lapse imaging was performed on cultured human HGF-1 fibroblast-like cells after staining using Live/Dead®. Image analysis showed a higher mortality rate in the presence of composite A than composite B. The viability rate decreased in a time-dependent manner during the 5 h of exposure. Morphological alterations were associated with toxic effects; cells were enlarged and more rounded in the presence of composite A as shown by F-actin and cell nuclei staining. Resazurin assay was used to confirm the active potential of composites in cell metabolism; results showed severe cytotoxic effects in the presence of both no light-curing composites after 24 h of direct contact. However, extracts of polymerized composites induced a moderate decrease in cell metabolism after the same incubation period. Composite B was significantly better tolerated than composite A at all investigated end points and all time points. The finding confirmed that the used CLSM method was sufficiently sensitive to differentiate the biocompatibility behavior of two composites based on similar methacrylate monomers.
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Affiliation(s)
- Ghania Nina Attik
- Laboratoire des Multimatériaux et Interfaces, UMR CNRS 5615, Université Lyon1, Villeurbanne, France.
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Undisz A, Geuther E, Völpel A, Watts DC, Rettenmayr M, Sigusch BW. Substrate-free multi-cellular aggregates of human gingival fibroblasts-fabrication, biomechanics and significance for tissue regeneration. Dent Mater 2013; 29:332-8. [PMID: 23287407 DOI: 10.1016/j.dental.2012.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 12/05/2012] [Accepted: 12/05/2012] [Indexed: 11/29/2022]
Abstract
OBJECTIVES We fabricate multi-cellular aggregates of human gingival fibroblasts (hGFs) using a novel in vivo method that omits supportive flexible substrates. On the basis of the multi-cellular aggregates, constructive and destructive effects of mechanical stimulation are investigated. METHODS hGFs were seeded onto aligned glass slides (one fixed, one mobile) with an initial gap <30 μm between their connecting edges. After the cells adhere, one of the glass slides is displaced using high precision threads and a piezoelectric element, widening the gap gradually. RESULTS After several days of gradually widening the gap, multiple multi-cellular hGF aggregates formed, bridging the gap between the glass slides. The effects of discrete displacement events on previously established multi-cellular aggregates ranged from considerable growth and consolidation to collapse and disintegration. A quantitative criterion for assessing the probability for collapse/disintegration of hGF multi-cellular aggregates based on evaluating the meniscus curvature at the free edges before and after displacement is presented and discussed. The curvature is suggested as a representative parameter to characterize the mechanical condition of multi-cellular aggregates, as it is affected by adhesion of cells to the glass slides, cohesion inside the multi-cellular aggregate and the external mechanical load generated by the displacement of the glass slides. SIGNIFICANCE The presented results clarify the potential and limitations of using mechanical stimulation for initiating and controlling regeneration of (gingival) tissue. Further potential applications include usage as biological substrate for co-culturing hierarchical tissue with multiple cell types (e.g. for vessels) and bio-membranes for filters (e.g. in microfluidics).
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Affiliation(s)
- Andreas Undisz
- Institute of Materials Science and Technology, Friedrich-Schiller-University Jena, Loebdergraben 32, 07743 Jena, Germany.
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Creep deformation of restorative resin-composites intended for bulk-fill placement. Dent Mater 2012; 28:928-35. [PMID: 22656273 DOI: 10.1016/j.dental.2012.04.038] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 04/30/2012] [Accepted: 04/30/2012] [Indexed: 10/28/2022]
Abstract
OBJECTIVES To determine the creep deformation of several "bulk-fill" resin-composite formulations in comparison with some other types. METHODS Six resin-composites; four bulk-fill and two conventional were investigated. Stainless steel split molds (4 mm × 6 mm) were used to prepare cylindrical specimens for creep testing. Specimens were thoroughly irradiated with 650 mW cm(-2). A total of 10 specimens for each material were divided into two groups (n = 5) according to the storage condition; Group A stored dry at 37 °C for 24h and Group B stored in distilled water at 37 °C in an incubator for 24h. Each specimen was loaded (20 MPa) for 2h and unloaded for 2h. The strain deformation was recorded continuously for 4h. Statistical analysis was performed using a two-way ANOVA followed by one-way ANOVA and the Bonferroni post hoc test at a significance level of a = 0.05. RESULTS The maximum creep strain % ranged from 0.72% up to 1.55% for Group A and the range for Group B increased from 0.79% up to 1.80% due to water sorption. Also, the permanent set ranged from 0.14% up to 0.47% for Group A and from 0.20% up to 0.59% for Group B. Dependent on the material and storage condition, the percentage of creep strain recovery ranged between 64% and 81%. Increased filler loading in the bulk-fill materials decreased the creep strain magnitude. SIGNIFICANCE Creep deformation of all studied resin-composites increased with wet storage. The "bulk-fill" composites exhibited an acceptable creep deformation and within the range exhibited by other resin-composites.
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