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Mokeem LS, Garcia IM, Melo MA. Degradation and Failure Phenomena at the Dentin Bonding Interface. Biomedicines 2023; 11:biomedicines11051256. [PMID: 37238927 DOI: 10.3390/biomedicines11051256] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 04/20/2023] [Accepted: 04/22/2023] [Indexed: 05/28/2023] Open
Abstract
Damage in the bonding interface is a significant factor that leads to premature failure of dental bonded restorations. The imperfectly bonded dentin-adhesive interface is susceptible to hydrolytic degradation and bacterial and enzyme attack, severely jeopardizing restorations' longevity. Developing caries around previously made restorations, also called "recurrent or secondary caries," is a significant health problem. The replacement of restorations is the most prevailing treatment in dental clinics, leading to the so-called "tooth death spiral". In other words, every time a restoration is replaced, more tooth tissue is removed, increasing the size of the restorations until the tooth is eventually lost. This process leads to high financial costs and detriment to patients' quality of life. Since the complexity of the oral cavity makes prevention a challenging task, novel strategies in Dental Materials and Operative fields are required. This article briefly overviews the physiological dentin substrate, features of dentin bonding, challenges and clinical relevance. We discussed the anatomy of the dental bonding interface, aspects of the degradation at the resin-dentin interface, extrinsic and intrinsic factors affecting dental bonding longevity, perspectives on resin and collagen degradation and how these subjects are connected. In this narrative review, we also outlined the recent progress in overcoming dental bonding challenges through bioinspiration, nanotechnology and advanced techniques to reduce degradation and improve dental bonding longevity.
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Affiliation(s)
- Lamia Sami Mokeem
- Ph.D. Program in Biomedical Sciences, University of Maryland School of Dentistry, Baltimore, MD 21201, USA
| | - Isadora Martini Garcia
- Division of Operative Dentistry, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD 21201, USA
| | - Mary Anne Melo
- Division of Operative Dentistry, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD 21201, USA
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Spencer P, Ye Q, Kamathewatta NJB, Woolfolk SK, Bohaty BS, Misra A, Tamerler C. Chemometrics-Assisted Raman Spectroscopy Characterization of Tunable Polymer-Peptide Hybrids for Dental Tissue Repair. FRONTIERS IN MATERIALS 2021; 8:681415. [PMID: 34113623 PMCID: PMC8186416 DOI: 10.3389/fmats.2021.681415] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The interfaces that biological tissues form with biomaterials are invariably defective and frequently the location where failure initiates. Characterizing the phenomena that lead to failure is confounded by several factors including heterogeneous material/tissue interfaces. To seamlessly analyze across these diverse structures presents a wealth of analytical challenges. This study aims to develop a molecular-level understanding of a peptide-functionalized adhesive/collagen hybrid biomaterial using Raman spectroscopy combined with chemometrics approach. An engineered hydroxyapatite-binding peptide (HABP) was copolymerized in dentin adhesive and dentin was demineralized to provide collagen matrices that were partially infiltrated with the peptide-functionalized adhesive. Partial infiltration led to pockets of exposed collagen-a condition that simulates defects in adhesive/dentin interfaces. The spectroscopic results indicate that co-polymerizable HABP tethered to the adhesive promoted remineralization of the defects. The spatial distribution of collagen, adhesive, and mineral as well as crystallinity of the mineral across this heterogeneous material/tissue interface was determined using micro-Raman spectroscopy combined with chemometrics approach. The success of this combined approach in the characterization of material/tissue interfaces stems from its ability to extract quality parameters that are related to the essential and relevant portions of the spectral data, after filtering out noise and non-relevant information. This ability is critical when it is not possible to separate components for analysis such as investigations focused on, in situ chemical characterization of interfaces. Extracting essential information from complex bio/material interfaces using data driven approaches will improve our understanding of heterogeneous material/tissue interfaces. This understanding will allow us to identify key parameters within the interfacial micro-environment that should be harnessed to develop durable biomaterials.
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Affiliation(s)
- Paulette Spencer
- Institute for Bioengineering Research, University of Kansas, Lawrence, KS, United States
- Department of Mechanical Engineering, University of Kansas, Lawrence, KS, United States
- Bioengineering Program, University of Kansas, Lawrence, KS, United States
- Correspondence: Paulette Spencer, , Qiang Ye,
| | - Qiang Ye
- Institute for Bioengineering Research, University of Kansas, Lawrence, KS, United States
- Correspondence: Paulette Spencer, , Qiang Ye,
| | - Nilan J. B. Kamathewatta
- Institute for Bioengineering Research, University of Kansas, Lawrence, KS, United States
- Bioengineering Program, University of Kansas, Lawrence, KS, United States
| | - Sarah K. Woolfolk
- Institute for Bioengineering Research, University of Kansas, Lawrence, KS, United States
- Bioengineering Program, University of Kansas, Lawrence, KS, United States
| | - Brenda S. Bohaty
- Department of Pediatric Dentistry, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, United States
| | - Anil Misra
- Institute for Bioengineering Research, University of Kansas, Lawrence, KS, United States
- Department of Civil Engineering, University of Kansas, Lawrence, KS, United States
| | - Candan Tamerler
- Institute for Bioengineering Research, University of Kansas, Lawrence, KS, United States
- Department of Mechanical Engineering, University of Kansas, Lawrence, KS, United States
- Bioengineering Program, University of Kansas, Lawrence, KS, United States
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Sarikaya R, Song L, Yuca E, Xie SX, Boone K, Misra A, Spencer P, Tamerler C. Bioinspired multifunctional adhesive system for next generation bio-additively designed dental restorations. J Mech Behav Biomed Mater 2021; 113:104135. [PMID: 33160267 PMCID: PMC8101502 DOI: 10.1016/j.jmbbm.2020.104135] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 07/17/2020] [Accepted: 10/07/2020] [Indexed: 12/16/2022]
Abstract
Resin-based composite has overtaken dental amalgam as the most popular material for the repair of lost or damaged tooth structure. In spite of the popularity, the average composite lifetime is about half that of amalgam restorations. The leading cause of composite-restoration failure is decay at the margin where the adhesive is applied. The adhesive is intended to seal the composite/tooth interface, but the adhesive seal to dentin is fragile and readily degraded by acids, enzymes and other oral fluids. The inherent weakness of this material system is attributable to several factors including the lack of antimicrobial properties, remineralization capabilities and durable mechanical performance - elements that are central to the integrity of the adhesive/dentin (a/d) interfacial seal. Our approach to this problem offers a transition from a hybrid to a biohybrid structure. Discrete peptides are tethered to polymers to provide multi-bio-functional adhesive formulations that simultaneously achieve antimicrobial and remineralization properties. The bio-additive materials design combines several functional properties with the goal of providing an adhesive that will serve as a durable barrier to recurrent decay at the composite/tooth interface. This article provides an overview of our multi-faceted approach which uses peptides tethered to polymers and new polymer chemistries to achieve the next generation adhesive system - an adhesive that provides antimicrobial properties, repair of defective dentin and enhanced mechanical performance.
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Affiliation(s)
- Rizacan Sarikaya
- Institute for Bioengineering Research (IBER), University of Kansas (KU), 1530 W. 15th St, Lawrence, KS, 66045, USA; Department of Mechanical Engineering, University of Kansas (KU), 1530 W. 15th St, Lawrence, KS, 66045, USA
| | - Linyong Song
- Institute for Bioengineering Research (IBER), University of Kansas (KU), 1530 W. 15th St, Lawrence, KS, 66045, USA
| | - Esra Yuca
- Institute for Bioengineering Research (IBER), University of Kansas (KU), 1530 W. 15th St, Lawrence, KS, 66045, USA; Department of Molecular Biology and Genetics, Yildiz Technical University, Istanbul, 34210, Turkey
| | - Sheng-Xue Xie
- Institute for Bioengineering Research (IBER), University of Kansas (KU), 1530 W. 15th St, Lawrence, KS, 66045, USA
| | - Kyle Boone
- Institute for Bioengineering Research (IBER), University of Kansas (KU), 1530 W. 15th St, Lawrence, KS, 66045, USA; Bioengineering Program, University of Kansas, 1530 W. 15th St, University of Kansas (KU), Lawrence, KS, 66045, USA
| | - Anil Misra
- Institute for Bioengineering Research (IBER), University of Kansas (KU), 1530 W. 15th St, Lawrence, KS, 66045, USA; Civil, Environmental and Architectural Engineering Department, University of Kansas (KU), 1530 W. 15th St, Lawrence, KS, 66045, USA
| | - Paulette Spencer
- Institute for Bioengineering Research (IBER), University of Kansas (KU), 1530 W. 15th St, Lawrence, KS, 66045, USA; Department of Mechanical Engineering, University of Kansas (KU), 1530 W. 15th St, Lawrence, KS, 66045, USA; Bioengineering Program, University of Kansas, 1530 W. 15th St, University of Kansas (KU), Lawrence, KS, 66045, USA
| | - Candan Tamerler
- Institute for Bioengineering Research (IBER), University of Kansas (KU), 1530 W. 15th St, Lawrence, KS, 66045, USA; Department of Mechanical Engineering, University of Kansas (KU), 1530 W. 15th St, Lawrence, KS, 66045, USA; Bioengineering Program, University of Kansas, 1530 W. 15th St, University of Kansas (KU), Lawrence, KS, 66045, USA.
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Evaluation of Caries-Free Restorations Bonded with Various Adhesive Systems: In Vitro Study. Int J Dent 2020; 2020:5859835. [PMID: 32774375 PMCID: PMC7395994 DOI: 10.1155/2020/5859835] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 05/15/2020] [Accepted: 05/23/2020] [Indexed: 11/17/2022] Open
Abstract
Purpose. Secondary caries originate from a leakage pathway where oral acids can penetrate faster and demineralize the tooth substrate deeper which can be visualized by dye penetration. The ability to prevent secondary caries by contemporary adhesive systems was evaluated in this study. Dye penetration distance through leakage and into the tooth substrate adjacent to Class V restorations after artificial caries exposure was compared. Materials and Methods. Previously frozen extracted human molars were used to prepare the Class V cavities at the CEJ on axial surfaces. All cavities were restored with either the resin-composite or amalgam with or without resin adhesives: dry bonding: Super-Bond D-Liner II Plus; moist bonding: All-Bond 2; and self-etch bonding: AQ Bond and Clearfil Protect Bond. Two subgroups of Super-Bond D-Liner II Plus were immersed for 14 days at 37°C either in artificial saliva (negative control) or the artificial caries solution. The other groups were soaked in the artificial caries solution. The distance of dye penetration into the adjacent enamel, cementum/dentin, and tooth-resin interfaces was measured after immersion in 0.5% basic fuchsin dye for 24 h. The tooth-resin interfacial layer was investigated using SEM. Results. No dye penetration into the tooth-resin interface was found in Super-Bond D-Liner II Plus and AQ Bond groups which demonstrated a constant hybrid layer after a chemical challenge. The leakage distance at the cementum/dentin-resin interface of All-Bond 2, Clearfil Protect Bond, and non-adhesive amalgam (positive control) groups was significantly higher than the distance of dye penetration into the adjacent demineralized root surface (p<0.05). Conclusion. Caries associated with either amalgam or resin-composite restorations can be prevented using resin adhesives which can penetrate into the intact tooth substrate to form a stable hybrid layer. With caries-free restorations, tooth vitality may be conserved lifelong.
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Bauer LJ, Mustafa HA, Zaslansky P, Mantouvalou I. Chemical mapping of teeth in 2D and 3D: X-ray fluorescence reveals hidden details in dentine surrounding fillings. Acta Biomater 2020; 109:142-152. [PMID: 32294552 DOI: 10.1016/j.actbio.2020.04.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 03/24/2020] [Accepted: 04/03/2020] [Indexed: 01/15/2023]
Abstract
X-rays are frequently used for characterizing both tooth tissues and dental materials. Whereas radiographs and tomography utilize absorption contrast for retrieving details, chemical mapping is usually achieved by energy dispersive X-ray (EDX) analysis that is stimulated under vacuum in electron microscopes. However, the relatively dense mineralized composition of teeth, and the frequent inclusion of a large range of elements in filling materials raise the possibility that other X-ray based techniques such as X-ray fluorescence (XRF) spectroscopy may strongly contribute to investigations of a large variety of dental structures. By exploiting the fluorescence excited by micron sized X-rays (µXRF) it is possible to map minute quantities of a large range of elements (from aluminum to uranium), where spectra containing signals from multiple different elements can be resolved non-destructively and concomitantly. The high penetration depth of X-rays makes XRF highly effective at detecting variable compositions with information emerging from tooth tissues situated well beneath the sample surface. The method supports minimal sample preparation and, different from electron microscopy, it facilitates investigation of hydrated dental materials. Direct comparison of µXRF and confocal µXRF (CµXRF) with SEM-EDX reveals micro zones of chemical heterogeneity in the complex 3D architecture of root canal fillings. These methods reproducibly clarify the mutual arrangement of biomaterials in both fresh fillings as well as in repeatedly treated old teeth of unknown history. The results showcase the complementarity of X-ray and electron based elemental mapping for dental materials research. STATEMENT OF SIGNIFICANCE: Chemical characterization of mineralized tissues such as tooth dentine is often performed using energy dispersive X-ray spectroscopy (EDS/EDX) analysis by scanning electron microscopy (SEM). The widespread use of electron microscopes and simplified detector designs have made this form of chemical and structural analysis extremely popular. However, excitation by electrons is limited to the upper microns of the tissue, and these may not well represent the chemical composition of the bulk. Especially when heavier elements are of interest and when dental filling materials exhibit diffusion into the tooth, little is known about the spatial distribution. Here we show how complementary X-ray fluorescence data originating by electron and X-ray excitation can help visualize the distribution and impregnation of heavy elements through teeth, e.g. for root canal treatment.
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Affiliation(s)
- Leona J Bauer
- Institute for Optics and Atomic Physics, Technical University of Berlin, Hardenbergstr. 36, Berlin 10623, Germany
| | - Hawshan A Mustafa
- Department for Restorative and Preventive Dentistry, Centrum für Zahn-, Mund- und Kieferheilkunde, Charité-Universitätsmedizin Berlin, Aßmannshauser Str. 4-6, Berlin 14197, Germany
| | - Paul Zaslansky
- Department for Restorative and Preventive Dentistry, Centrum für Zahn-, Mund- und Kieferheilkunde, Charité-Universitätsmedizin Berlin, Aßmannshauser Str. 4-6, Berlin 14197, Germany.
| | - Ioanna Mantouvalou
- Institute for Optics and Atomic Physics, Technical University of Berlin, Hardenbergstr. 36, Berlin 10623, Germany; Current affiliation: Helmholtz Zentrum Berlin, Albert-Einstein-Str. 15, 12489 Berlin, Germany
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Multifunctional monomer acts as co-initiator and crosslinker to provide autonomous strengthening with enhanced hydrolytic stability in dental adhesives. Dent Mater 2019; 36:284-295. [PMID: 31806495 DOI: 10.1016/j.dental.2019.11.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 10/31/2019] [Accepted: 11/15/2019] [Indexed: 12/23/2022]
Abstract
OBJECTIVE The purpose of this study was to evaluate a new synthesized multifunctional monomer, aminosilane functionalized methacrylate (ASMA), containing polymerizable methacrylate, tertiary amine, and methoxysilane functionalities in dental adhesive formulations, and to investigate the polymerization kinetics, leachates, thermal and mechanical properties of copolymers. METHODS Adhesive contained HEMA/BisGMA (45/55, w/w) was used as a control, and mixtures based on HEMA/BisGMA/ASMA at the mass ratio of 45/(55-x)/x were used as experimental adhesive. Adhesives were characterized with regard to water miscibility, photo-polymerization behavior (Fourier transform infrared spectroscopy, FTIR), leached co-monomers (high performance liquid chromatography, HPLC), thermal properties (modulated differential scanning calorimeter, MDSC), and mechanical properties (dynamic mechanical analyzer, DMA). Stress relaxation times and the corresponding moduli, obtained from stress relaxation tests, are used in a simulated linear loading case. RESULTS As compared to the control, ASMA-containing adhesives showed higher water miscibility, lower viscosity, improved monomer-to-polymer conversion, significantly greater Tg and rubbery modulus. HPLC results indicated a substantial reduction of leached HEMA (up to 85wt%) and BisGMA (up to 55wt%) in ethanol. The simulation reveals that the ASMA-containing adhesive becomes substantially stiffer than the control. SIGNIFICANCE ASMA monomer plays multiple roles, i.e. it serves as both a co-initiator and crosslinker while also providing autonomous strengthening and enhanced hydrolytic stability in the adhesive formulations. This multifunctional monomer offers significant promise for improving the durability of the adhesive at the composite/tooth interface.
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Spencer P, Ye Q, Song L, Parthasarathy R, Boone K, Misra A, Tamerler C. Threats to adhesive/dentin interfacial integrity and next generation bio-enabled multifunctional adhesives. J Biomed Mater Res B Appl Biomater 2019; 107:2673-2683. [PMID: 30895695 PMCID: PMC6754319 DOI: 10.1002/jbm.b.34358] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 02/07/2019] [Accepted: 02/20/2019] [Indexed: 12/27/2022]
Abstract
Nearly 100 million of the 170 million composite and amalgam restorations placed annually in the United States are replacements for failed restorations. The primary reason both composite and amalgam restorations fail is recurrent decay, for which composite restorations experience a 2.0-3.5-fold increase compared to amalgam. Recurrent decay is a pernicious problem-the standard treatment is replacement of defective composites with larger restorations that will also fail, initiating a cycle of ever-larger restorations that can lead to root canals, and eventually, to tooth loss. Unlike amalgam, composite lacks the inherent capability to seal discrepancies at the restorative material/tooth interface. The low-viscosity adhesive that bonds the composite to the tooth is intended to seal the interface, but the adhesive degrades, which can breach the composite/tooth margin. Bacteria and bacterial by-products such as acids and enzymes infiltrate the marginal gaps and the composite's inability to increase the interfacial pH facilitates cariogenic and aciduric bacterial outgrowth. Together, these characteristics encourage recurrent decay, pulpal damage, and composite failure. This review article examines key biological and physicochemical interactions involved in the failure of composite restorations and discusses innovative strategies to mitigate the negative effects of pathogens at the adhesive/dentin interface. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B:2466-2475, 2019.
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Affiliation(s)
- Paulette Spencer
- Institute for Bioengineering Research, School of Engineering, University of Kansas, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA
- Department of Mechanical Engineering, University of Kansas,1530 W. 15th Street, Lawrence, KS 66045-7609, USA
| | - Qiang Ye
- Institute for Bioengineering Research, School of Engineering, University of Kansas, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA
| | - Linyong Song
- Institute for Bioengineering Research, School of Engineering, University of Kansas, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA
| | - Ranganathan Parthasarathy
- Department of Civil Engineering, Tennessee State University, 3500 John A Merritt Blvd, Nashville, TN 37209, USA
| | - Kyle Boone
- Institute for Bioengineering Research, School of Engineering, University of Kansas, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA
| | - Anil Misra
- Institute for Bioengineering Research, School of Engineering, University of Kansas, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA
- Department of Civil Engineering, University of Kansas, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA
| | - Candan Tamerler
- Institute for Bioengineering Research, School of Engineering, University of Kansas, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA
- Department of Mechanical Engineering, University of Kansas,1530 W. 15th Street, Lawrence, KS 66045-7609, USA
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Liu Q, Wu B, Yu Q, Wang Y. Immobilization of quaternary ammonium based antibacterial monomer onto dentin substrate by non-thermal atmospheric plasma. Dent Mater J 2019; 38:821-829. [PMID: 31366767 DOI: 10.4012/dmj.2018-267] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Use of non-thermal atmospheric plasma (NTAP) brush on immobilization of dimethylaminohexadecyl methacrylate (DMAHDM) onto dentin bonding substrate, and resulting antibacterial activity against Streptococcus mutans were investigated. A bonding substrate with several-micron-demineralized layer was created from human dentin. DMAHDM was applied onto the demineralized layer with or without plasma exposure. Scanning electron microscopy (SEM) and Fourier transformed infrared (FTIR) spectroscopy were employed to verify immobilization/grafting of DMAHDM onto the substrate. Antibacterial activity of the resulting substrate was assessed by using colony-forming unit (CFU) and confocal scanning laser microscopy. Effects of saliva pellicle treatment and aging process on the above substrate were also evaluated. The SEM/FTIR results demonstrated that NTAP could induce DMAHDM immobilization onto dentin substrate, which was further verified via quantitative FTIR analysis. Comparing with non-plasma-treated, the plasmatreated substrate, with CFU 4 log lower, exhibited much stronger inhibitory effects, which were minimally affected by saliva or aging. The DMAHDM-immobilized dentin substrate showed effective and sustained antibacterial characteristics.
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Affiliation(s)
- Qi Liu
- Department of Stomatology, Nanfang Hospital, Southern Medical University.,Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City School of Dentistry
| | - Buling Wu
- Department of Stomatology, Nanfang Hospital, Southern Medical University
| | - Qingsong Yu
- Department of Mechanical and Aerospace Engineering, University of Missouri
| | - Yong Wang
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City School of Dentistry
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Trevelin LT, Villanueva J, Zamperini CA, Mathew MT, Matos AB, Bedran-Russo AK. Investigation of five α-hydroxy acids for enamel and dentin etching: Demineralization depth, resin adhesion and dentin enzymatic activity. Dent Mater 2019; 35:900-908. [PMID: 30975484 DOI: 10.1016/j.dental.2019.03.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 03/11/2019] [Accepted: 03/15/2019] [Indexed: 01/02/2023]
Abstract
OBJECTIVES Surface conditioning of enamel and dentin is a key step during adhesive restorative procedures and strategies. The aim of this study was to investigate the effectiveness of five α-hydroxy-acids (AHAs) as enamel and dentin surface etchants. METHODS Enamel and dentin specimens were prepared from human molars to determine the depth of demineralization by optical profilometry (Δz), the resin bond strength to enamel and dentin (μTBS), the micro-permeability of dentin-resin interfaces, and the gelatinolytic activity of dentin matrix induced by AHAs [glycolic (GA), lactic (LA), citric (CA), malic (MI) and tartaric (TA)] and controls [phosphoric (PA) and maleic (MA)]. All acids were prepared at 35% concentration. Adhesion studies employed Adper Single Bond Plus bonding system. Data were individually processed and analyzed by ANOVA, post-hoc tests and Pearson correlations (α = 0.05). RESULTS AHA exhibited statistically lower depth of demineralization of enamel and dentin (average 4 fold) than controls (p < 0.001). In enamel, MA and PA etching resulted in higher μTBS than AHA groups (p < 0.001). In dentin, GA, TA, CI and LA etching resulted in statistically similar μTBS than PA (p < 0.05). The hybrid-layer (HL) thickness and interfacial micro-permeability intensity were statistically lower for AHA groups (p < 0.05). A significant positive correlation was observed between the intensity of micro-permeability and the thickness of HL (p < 0.05). AHA etchants elicited lower dentin enzymatic activity than controls (p < 0.05). SIGNIFICANCE AHAs effectively etched enamel and dentin surfaces. In particular, GA and TA resulted in suitable μTBS and sealing ability as well as induced less gelatinolytic activity in dentin than PA and MA.
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Affiliation(s)
- Lívia Tosi Trevelin
- Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, UIC, Chicago, IL, USA; Department of Operative Dentistry, College of Dentistry, University of São Paulo, USP, São Paulo, SP, Brazil
| | - Jose Villanueva
- Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, UIC, Chicago, IL, USA
| | - Camila A Zamperini
- Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, UIC, Chicago, IL, USA
| | - Mathew T Mathew
- Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, UIC, Chicago, IL, USA
| | - Adriana Bona Matos
- Department of Operative Dentistry, College of Dentistry, University of São Paulo, USP, São Paulo, SP, Brazil
| | - Ana K Bedran-Russo
- Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, UIC, Chicago, IL, USA.
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Song L, Ye Q, Ge X, Misra A, Tamerler C, Spencer P. New silyl-functionalized BisGMA provides autonomous strengthening without leaching for dental adhesives. Acta Biomater 2019; 83:130-139. [PMID: 30366133 DOI: 10.1016/j.actbio.2018.10.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 09/30/2018] [Accepted: 10/22/2018] [Indexed: 12/27/2022]
Abstract
Resin-based composite has overtaken dental amalgam as the most popular material for direct restorative dentistry. In spite of this popularity the clinical lifetime of composite restorations is threatened by recurrent decay. Degradation of the adhesive leads to gaps at the composite/tooth interface-bacteria, bacterial by-products and fluids infiltrate the gaps leading to recurrent decay and composite restoration failure. The durability of resin-dentin bonds is a major problem. We address this problem by synthesizing silyl-functionalized BisGMA (e.g., silyl-BisGMA), formulating dental adhesives with the new monomer and determining the physicochemical properties and leaching characteristics of the silyl-BisGMA adhesives. Silyl-BisGMA was synthesized by stoichiometric amounts of BisGMA and 3-isocyanatopropyl trimethoxysilane (IPTMS). The control adhesive was a mixture based on HEMA/BisGMA (45/55, w/w). In the experimental formulations, BisGMA was partially or completely replaced by silyl-BisGMA. Water miscibility, polymerization behavior (Fourier transform infrared spectroscopy, FTIR), thermal property (modulated differential scanning calorimetry, MDSC), mechanical properties in dry and wet conditions (dynamic mechanical analysis, DMA), and leached species (HPLC) were investigated. Data from all tests were submitted to appropriate statistical analysis (α = 0.05). Silyl-BisGMA-containing adhesives exhibited comparable water miscibility, lower viscosities, and significantly improved degree of conversion of CC bond as compared to the control. After 4 weeks aqueous aging, the glass transition temperature and rubbery moduli of the experimental copolymers were significantly greater than the control (p < 0.05). HPLC results indicated a substantial reduction of leached HEMA (up to 99 wt%) and BisGMA (up to 90 wt%). By introducing silyl-functional group, the new BisGMA derivative exhibited potential as a monomer that can lead to dental adhesives with improved mechanical properties and reduced leaching under conditions relevant to the oral environment. STATEMENT OF SIGNIFICANCE: The low-viscosity adhesive that bonds the composite to the tooth (enamel and dentin) is intended to seal and stabilize the composite/tooth interface, but it degrades leading to a breach at the composite/tooth margin. As the most popular crosslinking monomer in adhesives, Bisphenol A-glycerolate dimethacrylate (BisGMA) has limitations, e.g. susceptible to hydrolysis and concomitant property degradation. A methoxysilyl-functionalized BisGMA derivative (silyl-BisGMA) was introduced in this work to respond to these limitations. Our results indicated that by introducing silyl-BisGMA, higher crosslinked networks were obtained without sacrificing the homogeneity, and the leached amount of HEMA was reduced up to 99%. This novel resin offers potential benefits including prolonging the functional lifetime of dental resin materials.
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Parthasarathy R, Misra A, Song L, Ye Q, Spencer P. Structure-property relationships for wet dentin adhesive polymers. Biointerphases 2018; 13:061004. [PMID: 30558430 PMCID: PMC6296910 DOI: 10.1116/1.5058072] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 11/27/2018] [Accepted: 11/28/2018] [Indexed: 12/23/2022] Open
Abstract
Dentin adhesive systems for composite tooth restorations are composed of hydrophilic/hydrophobic monomers, solvents, and photoinitiators. The adhesives undergo phase separation and concomitant compositional change during their application in the wet oral environment; phase separation compromises the quality of the hybrid layer in the adhesive/dentin interface. In this work, the adhesive composition in the hybrid layer can be represented using the phase boundaries of a ternary phase diagram for the hydrophobic monomer/hydrophilic monomer/water system. The polymer phases, previously unaccounted for, play an important role in determining the mechanical behavior of the bulk adhesive, and the chemomechanical properties of the phases are intimately related to the effects produced by differences in the hydrophobic-hydrophilic composition. As the composition of the polymer phases varies from hydrophobic-rich to hydrophilic-rich, the amount of the adsorbed water and the nature of polymer-water interaction vary nonlinearly and strongly correlate with the change in elastic moduli under wet conditions. The failure strain, loss modulus, and glass transition temperature vary nonmonotonically with composition and are explained based upon primary and secondary transitions observed in dynamic mechanical testing. Due to the variability in composition, the assignment of mechanical properties and the choice of suitable constitutive models for polymer phases in the hybrid layer are not straightforward. This work investigates the relationship between composition and chemomechanical properties of the polymer phases formed on the water-adhesive phase boundary using quasistatic and dynamic mechanical testing, mass transfer experiments, and vibrational spectroscopy.
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Affiliation(s)
- Ranganathan Parthasarathy
- Department of Civil and Architectural Engineering, Tennessee State University, 3500 John A Merritt Blvd, Nashville, Tennessee 37209
| | - Anil Misra
- Department of Civil and Environmental Engineering, Institute for Bioengineering Research, University of Kansas, 5104B Learned Hall, 1530 W 15th Street, Lawrence, Kansas 66045
| | - Linyong Song
- Institute for Bioengineering Research, University of Kansas, 5104A Learned Hall, 1530 W 15th Street, Lawrence, Kansas 66045
| | - Qiang Ye
- Institute for Bioengineering Research, University of Kansas, 5101E Learned Hall, 1530 W 15th Street, Lawrence, Kansas 66045
| | - Paulette Spencer
- Department of Mechanical Engineering, Institute for Bioengineering Research, University of Kansas, 3111 Learned Hall, 1530 W 15th Street, Lawrence, Kansas 66045
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Esteves SRMS, Huhtala MFRL, Gomes APM, Ye Q, Spencer P, De Paiva Gonçalves SE. Longitudinal Effect of Surface Treatments Modified by NaOCl-Induced Deproteinization and Nd:YAG Laser on Dentin Permeability. Photomed Laser Surg 2016; 34:68-75. [DOI: 10.1089/pho.2015.3977] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
| | | | - Ana Paula Martins Gomes
- Department of Restorative Dentistry, São José dos Campos School of Dentistry, University Estadual Paulista, SP, Brazil
| | - Qiang Ye
- Bioengineering Research Center Laboratories The University of Kansas, School of Engineering, Bioengineering Research Center, Lawrence, Kansas
| | - Paulette Spencer
- Bioengineering Research Center Laboratories The University of Kansas, School of Engineering, Bioengineering Research Center, Lawrence, Kansas
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Effects of water-aging on self-healing dental composite containing microcapsules. J Dent 2016; 47:86-93. [PMID: 26808158 DOI: 10.1016/j.jdent.2016.01.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Revised: 01/08/2016] [Accepted: 01/19/2016] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVES The objectives of this study were to develop a self-healing dental composite containing poly(urea-formaldehyde) (PUF) shells with triethylene glycol dimethacrylate (TEGDMA) and N,N-dihydroxyethyl-p-toluidine (DHEPT) as healing liquid, and to investigate the mechanical properties of the composite and its self-healing efficacy after water-aging for 6 months. METHODS PUF microspheres were synthesized encapsulating a TEGDMA-DHEPT healing liquid. Composite containing 30% of a resin matrix and 70% of glass fillers by mass was incorporated with 0%, 2.5%, 5%, 7.5% and 10% of microcapsules. A flexural test was used to measure flexural strength and elastic modulus. A single edge V-notched beam method was used to measure fracture toughness (KIC) and self-healing efficacy. Specimens were water-aged at 37 °C for 1 day to 6 months and then tested for self-healing. Fractured specimens were healed while being immersed in water to examine self-healing efficacy, in comparison with that in air. RESULTS Incorporation of up to 7.5% of microcapsules into the resin composite achieved effective self-healing, without adverse effects on the virgin mechanical properties of the composite (p>0.1). An excellent self-healing efficacy of 64-77% recovery was obtained (mean±sd; n=6). Six months of water-aging did not decrease the self-healing efficacy compared to 1 day (p>0.1). Exposure to water did not decrease the healing efficacy, compared to that healed in air (p>0.1). CONCLUSIONS A composite was developed with excellent self-healing efficacy even while being immersed in water. The self-healing efficacy did not decrease with increasing water-aging time for 6 months. CLINICAL SIGNIFICANCE The novel self-healing composite may be promising for dental applications to heal cracks, resist fracture, and increase the durability and longevity.
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Direct Tensile Strength and Characteristics of Dentin Restored with All-Ceramic, Resin-Composite, and Cast Metal Prostheses Cemented with Resin Adhesives. BIOMED RESEARCH INTERNATIONAL 2015; 2015:656948. [PMID: 26539520 PMCID: PMC4619853 DOI: 10.1155/2015/656948] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 12/12/2014] [Indexed: 11/17/2022]
Abstract
A dentin-cement-prosthesis complex restored with either all-porcelain, cured resin-composite, or cast base metal alloy and cemented with either of the different resin cements was trimmed into a mini-dumbbell shape for tensile testing. The fractured surfaces and characterization of the dentin-cement interface of bonded specimens were investigated using a Scanning Electron Microscope. A significantly higher tensile strength of all-porcelain (12.5 ± 2.2 MPa) than that of cast metal (9.2 ± 3.5 MPa) restorations was revealed with cohesive failure in the cement and failure at the prosthesis-cement interface in Super-Bond C&B group. No significant difference in tensile strength was found among the types of restorations using the other three cements with adhesive failure on the dentin side and cohesive failure in the cured resin. SEM micrographs demonstrated the consistent hybridized dentin in Super-Bond C&B specimens that could resist degradation when immersed in hydrochloric acid followed by NaOCl solutions whereas a detached and degraded interfacial layer was found for the other cements. The results suggest that when complete hybridization of resin into dentin occurs tensile strength at the dentin-cement is higher than at the cement-prosthesis interfaces. The impermeable hybridized dentin can protect the underlying dentin and pulp from acid demineralization, even if detachment of the prosthesis has occurred.
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Ge X, Ye Q, Song L, Spencer P, Laurence JS. Effect of crosslinking density of polymers and chemical structure of amine-containing monomers on the neutralization capacity of dentin adhesives. Dent Mater 2015; 31:1245-53. [PMID: 26342639 DOI: 10.1016/j.dental.2015.08.153] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 06/18/2015] [Accepted: 08/17/2015] [Indexed: 10/23/2022]
Abstract
OBJECTIVES Neutralization of the acidic micro-environment at the tooth/material interface is expected to provide enhanced durability for dental composite restorations. The objective of this study is to explore the effect of amine-containing monomer formulations and the crosslinking density of the resultant polymers on the neutralization capacity. MATERIALS AND METHODS The co-monomer system was varied systematically to obtain different proportions of Bisphenol A glycerolate dimethacrylate (BisGMA) and 2-hydroxyethyl methacrylate (HEMA), while maintaining a constant amount of amine-containing methacrylate monomer. A series of amine-containing monomers covering a range of pKa values were examined. Crosslinking density of formed copolymers was controlled by adjusting the weight content of the dimethacrylate monomer BisGMA. Lactic acid (LA) was used as a probe to analyze the effectiveness of the basic polymers to neutralize acid. The neutralization capacity of each amine-containing crosslinked copolymer was characterized by measuring pH as a function of time when the specimens were soaked in 1-mM LA solution, and the results were compared to the control formulations composed solely of BisGMA and HEMA. Polymer surfaces were examined using the methyl orange (MO) assay to quantify the amount of accessible amine groups. RESULTS For each amine-containing crosslinked co-polymer, the neutralization capacity is enhanced by decreasing crosslinking density (e.g., by reducing BisGMA concentration in the formulation). In addition, more amine groups were accessible when crosslinking density was decreased. For different amine-containing polymers with the same BisGMA concentration, the neutralization capacity is higher when the amino monomers with higher pKa values were used in the formulations. SIGNIFICANCE This is the first time that the neutralization capacity based on crosslinked dental polymers has been studied. The information is important for future development of durable dentin adhesives.
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Affiliation(s)
- Xueping Ge
- Bioengineering Research Center, School of Engineering, University of Kansas, Lawrence, KS, USA
| | - Qiang Ye
- Bioengineering Research Center, School of Engineering, University of Kansas, Lawrence, KS, USA
| | - Linyong Song
- Bioengineering Research Center, School of Engineering, University of Kansas, Lawrence, KS, USA
| | - Paulette Spencer
- Bioengineering Research Center, School of Engineering, University of Kansas, Lawrence, KS, USA; Department of Mechanical Engineering, University of Kansas, Lawrence, KS, USA.
| | - Jennifer S Laurence
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, USA.
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Ge X, Ye Q, Song L, Misra A, Spencer P. Synthesis and evaluation of novel siloxane-methacrylate monomers used as dentin adhesives. Dent Mater 2014; 30:1073-87. [PMID: 24993811 DOI: 10.1016/j.dental.2014.06.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Revised: 05/07/2014] [Accepted: 06/09/2014] [Indexed: 11/17/2022]
Abstract
OBJECTIVES The objectives of this study were to synthesize two new siloxane-methacrylate (SM) monomers for application in dentin adhesives and to investigate the influence of different functionality of the siloxane-containing monomers on the adhesive photopolymerization, water sorption, and mechanical properties. METHODS Two siloxane-methacrylate monomers (SM1 and SM2) with four and eight methacrylate groups were synthesized. Dentin adhesives containing BisGMA, HEMA and the siloxane-methacrylate monomers were photo-polymerized. The experimental adhesives were compared with the control adhesive (HEMA/BisGMA, 45/55, w/w) and characterized with regard to degree of conversion (DC), water miscibility of the liquid resin, water sorption and dynamic mechanical analysis (DMA). RESULTS The experimental adhesives exhibited improved water miscibility as compared to the control. When cured in the presence of 12 wt% water to simulate the wet environment of the mouth, the SM-containing adhesives showed DC comparable to the control. The experimental adhesives showed higher rubbery modulus than the control under dry conditions. Under wet conditions, the mechanical properties of the formulations containing SM monomer with increased functionality were comparable with the control, even with more water sorption. SIGNIFICANCE The concentration and functionality of the newly synthesized siloxane-methacrylate monomers affected the water miscibility, water sorption and mechanical properties of the adhesives. The experimental adhesives show improved water compatibility compared with the control. The mechanical properties were enhanced with an increase of the functionality of the siloxane-containing monomers. The results provide critical structure/property relationships and important information for future development of durable, versatile siloxane-containing dentin adhesives.
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Affiliation(s)
- Xueping Ge
- Bioengineering Research Center, School of Engineering, University of Kansas, Lawrence, KS, USA
| | - Qiang Ye
- Bioengineering Research Center, School of Engineering, University of Kansas, Lawrence, KS, USA.
| | - Linyong Song
- Bioengineering Research Center, School of Engineering, University of Kansas, Lawrence, KS, USA
| | - Anil Misra
- Department of Civil Engineering, University of Kansas, Lawrence, KS, USA
| | - Paulette Spencer
- Bioengineering Research Center, School of Engineering, University of Kansas, Lawrence, KS, USA; Department of Mechanical Engineering, University of Kansas, Lawrence, KS, USA.
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Non-thermal atmospheric plasmas in dental restoration: improved resin adhesive penetration. J Dent 2014; 42:1033-42. [PMID: 24859333 DOI: 10.1016/j.jdent.2014.05.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 05/09/2014] [Accepted: 05/13/2014] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE To investigate the influence of non-thermal plasma treatment on the penetration of a model dental adhesive into the demineralized dentine. METHODS Prepared dentine surfaces were conditioned with Scotchbond Universal etchant for 15s and sectioned equally perpendicular to the etched surfaces. The separated halves were randomly selected for treatment with an argon plasma brush (input current 6mA, treatment time 30s) or gentle argon air blowing (treatment time 30s, as control). The plasma-treated specimens and control specimens were applied with a model adhesive containing 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy) phenyl]-propane (BisGMA) and 2-hydroxyethyl methacrylate (HEMA) (mass ratio of 30/70), gently air-dried for 5s, and light-cured for 20s. Cross-sectional specimens were characterized using micro-Raman spectral mapping across the dentine, adhesive/dentine interface, and adhesive layer at 1-μm spatial resolution. SEM was also employed to examine the adhesive/dentine interfacial morphology. RESULTS The micro-Raman result disclosed that plasma treatment significantly improved the penetration of the adhesive, evidenced by the apparently higher content of the adhesive at the adhesive/dentine interface as compared to the control. Specifically, the improvement of the adhesive penetration using plasma technique was achieved by dramatically enhancing the penetration of hydrophilic monomer (HEMA), while maintaining the penetration of hydrophobic monomer (BisGMA). Morphological observation at the adhesive/dentine interface using SEM also confirmed the improved adhesive penetration. The results further suggested that plasma treatment could benefit polymerization of the adhesive, especially in the interface region. CONCLUSION The significant role of the non-thermal plasma brush in improving the adhesive penetration into demineralized dentine has been demonstrated. The results obtained may offer a better prospect of using plasma in dental restoration to optimize adhesion between tooth substrate and restorative materials.
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Song L, Ye Q, Ge X, Misra A, Laurence JS, Berrie CL, Spencer P. Synthesis and evaluation of novel dental monomer with branched carboxyl acid group. J Biomed Mater Res B Appl Biomater 2014; 102:1473-84. [PMID: 24596134 DOI: 10.1002/jbm.b.33126] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 01/23/2014] [Accepted: 02/18/2014] [Indexed: 11/07/2022]
Abstract
To enhance the water miscibility and increase the mechanical properties of dentin adhesives, a new glycerol-based monomer with vinyl and carboxylic acid, 4-((1,3-bis(methacryloyloxy)propan-2-yl)oxy)-2-methylene-4-oxobutanoic acid (BMPMOB), was synthesized and characterized. Dentin adhesive formulations containing 2-hydroxyethyl methacrylate (HEMA), 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy) phenyl]propane (BisGMA), and BMPMOB were characterized with regard to real-time photopolymerization behavior, water sorption, dynamic mechanical analysis, and microscale three-dimensional internal morphologies and compared with HEMA/BisGMA controls. The experimental adhesive copolymers showed higher glass transition temperature and rubbery moduli, as well as improved water miscibility compared to the controls. The enhanced properties of the adhesive copolymers indicated that BMPMOB is a promising comonomer for dental restorative materials.
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Affiliation(s)
- Linyong Song
- Bioengineering Research Center, University of Kansas, Lawrence, Kansas, 66045; School of Chemistry and Chemical Engineering, Anhui University, Hefei, China
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Dietschi D, Argente A, Krejci I, Mandikos M. In Vitro Performance of Class I and II Composite Restorations: A Literature review on Nondestructive Laboratory Trials—Part II. Oper Dent 2013; 38:E182-200. [PMID: 23725090 DOI: 10.2341/12-020b-lit] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
ABSTRACT
A literature review was conducted on adhesive Class I and II restorations and nondestructive in vitro tests using the PubMed/Medline database for the 1995-2010 period. The first part of this review has presented and critically appraised selected literature dealing with the quality and in vitro behavior of adhesive Class II restorations using photoelasticity, finite element analysis, and microleakage study protocols. This second part reviews additional parameters, which are deformation and fracture resistance to cyclic loading, shrinkage stress and tooth deformation following restoration placement, bond strength (microtensile, tensile, and shear tests), and marginal and internal adaptation. In addition, a “relevance score” has been proposed that aims to classify the different study protocols according, firstly, to the resulting quality, quantity, and consistency of the evidence and then, secondly, to their potential clinical relevance, as estimated by their ability to simulate oral and biomechanical strains. The highest clinical relevance was attributed to marginal and internal adaptation studies, following cyclic loading in a moist environement. However, a combination of in vitro protocols will have an even greater predictive potential and has to be considered as a crucial preclinical research approach with which to investigate the numerous restorative configurations that cannot be efficiently and rapidly tested in vivo.
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Affiliation(s)
- D Dietschi
- Didier Dietschi, DMD, PhD, privat-docent, School of Dentistry, University of Geneva, Cariology & Endodontics, Geneva, Geneva CH 1205, Switzerland
| | - A Argente
- Ana Argente, DMD, School of Dentistry, University of Geneva, Cariology & Endodontics, Geneva, Geneva CH 1205, Switzerland
| | - I Krejci
- Ivo Krejci, Geneva School of Dentistry, Department of Cariology and Endodontology, Geneva, 1205, Switzerland
| | - M Mandikos
- Michael Mandikos, Brisbane Prosthodontics, Graceville, Queensland 4075, Australia
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Bohaty BS, Ye Q, Misra A, Sene F, Spencer P. Posterior composite restoration update: focus on factors influencing form and function. Clin Cosmet Investig Dent 2013; 5:33-42. [PMID: 23750102 PMCID: PMC3666491 DOI: 10.2147/ccide.s42044] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Indexed: 12/01/2022] Open
Abstract
Restoring posterior teeth with resin-based composite materials continues to gain popularity among
clinicians, and the demand for such aesthetic restorations is increasing. Indeed, the most common
aesthetic alternative to dental amalgam is resin composite. Moderate to large posterior composite
restorations, however, have higher failure rates, more recurrent caries, and increased frequency of
replacement. Investigators across the globe are researching new materials and techniques that will
improve the clinical performance, handling characteristics, and mechanical and physical properties
of composite resin restorative materials. Despite such attention, large to moderate posterior
composite restorations continue to have a clinical lifetime that is approximately one-half that of
the dental amalgam. While there are numerous recommendations regarding preparation design,
restoration placement, and polymerization technique, current research indicates that restoration
longevity depends on several variables that may be difficult for the dentist to control. These
variables include the patient’s caries risk, tooth position, patient habits, number of
restored surfaces, the quality of the tooth–restoration bond, and the ability of the
restorative material to produce a sealed tooth–restoration interface. Although clinicians
tend to focus on tooth form when evaluating the success and failure of posterior composite
restorations, the emphasis must remain on advancing our understanding of the clinical variables that
impact the formation of a durable seal at the restoration–tooth interface. This paper
presents an update of existing technology and underscores the mechanisms that negatively impact the
durability of posterior composite restorations in permanent teeth.
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Affiliation(s)
- Brenda S Bohaty
- Department of Pediatric Dentistry, University of Missouri-Kansas City School of Dentistry, Kansas City, MO, USA; ; Department of Pediatric Dentistry, Children's Mercy Hospital, Kansas City, MO, USA
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Zhang Y, Wang Y. Effect of application mode on interfacial morphology and chemistry between dentine and self-etch adhesives. J Dent 2012; 41:231-40. [PMID: 23153573 DOI: 10.1016/j.jdent.2012.11.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Revised: 10/17/2012] [Accepted: 11/02/2012] [Indexed: 10/27/2022] Open
Abstract
OBJECTIVE To investigate the influence of application mode on the interfacial morphology and chemistry between dentine and self-etch adhesives with different aggressiveness. METHODS The occlusal one-third of the crown was removed from un-erupted human third molars, followed by abrading with 600 grit SiC under water. Rectangular dentine slabs were prepared by sectioning the tooth specimens perpendicular to the abraded surfaces. The obtained dentine slabs were treated with one of the two one-step self-etch adhesives: Adper Easy Bond (AEB, pH∼2.5) and Adper Prompt L-Pop (APLP, pH∼0.8) with (15s, active application) or without (15s, inactive application) agitation. The dentine slabs were fractured and the exposed adhesive/dentine (A/D) interfaces were examined with micro-Raman spectroscopy and scanning electron microscopy (SEM). RESULTS The interfacial morphology, degree of dentine demineralization (DD) and degree of conversion (DC) of the strong self-etch adhesive APLP showed more significant dependence on the application mode than the mild AEB. APLP exhibited inferior bonding at the A/D interface if applied without agitation, evidenced by debonding from the dentine substrate. The DDs and DCs of the APLP with agitation were higher than those of without agitation in the interface, in contrast to the comparable DD and DC values of two AEB specimen groups with different application modes. Raman spectral analysis revealed the important role of chemical interaction between acid monomers of self-etch adhesives and dentine in the above observations. CONCLUSION The chemical interaction with dentine is especially important for improving the DC of the strong self-etching adhesive at the A/D interface. Agitation could benefit polymerization efficacy of the strong self-etch adhesive through enhancing the chemical interaction with tooth substrate.
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Affiliation(s)
- Ying Zhang
- University of Missouri-Kansas City School of Dentistry, 650 E 25th Street, Kansas City, MO 64108, USA
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Chen L, Xu C, Wang Y, Shi J, Yu Q, Li H. BisGMA/TEGDMA dental nanocomposites containing glyoxylic acid-modified high-aspect ratio hydroxyapatite nanofibers with enhanced dispersion. Biomed Mater 2012; 7:045014. [PMID: 22689264 DOI: 10.1088/1748-6041/7/4/045014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The purpose of this research was to investigate the influence of the glyoxylic acid (GA) modification of hydroxyapatite (HAP) nanofibers on their dispersion in bisphenol A glycidyl methacrylate (BisGMA)/triethylene glycol dimethacrylate (TEGDMA) dental composites and also to investigate the mechanical properties, water absorption and water solubility of the resulting dental resins and composites. Scanning/transmission electron microscopy images showed that microsized HAP nanofiber bundles could be effectively broken down into individual HAP nanofibers with an average length of ∼15 µm after the surface modification process. Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy and thermal gravimetric analysis characterization confirmed that GA was chemically grafted on the HAP nanofiber surface, hypothetically by reacting with the amine group on the HAP nanofiber surface. The enhanced dispersion of HAP nanofibers in the dental matrix led to increased biaxial flexural strength (BFS) compared with the corresponding dental resins and composites filled with untreated HAP nanofibers. In addition, impregnation of small mass fractions of the GA-modified HAP nanofibers into the BisGMA/TEGDMA dental resins (5 wt%, 10 wt%) or composites (2 wt%, 3 wt%) could also substantially improve the BFS in comparison with the controls (pure resins or dental composites filled with silica particles alone). Larger mass fractions could not increase the mechanical property further or even degraded the BFS values. Water behavior testing results indicated that the addition of the GA-modified HAP nanofibers resulted in higher water absorption and water solubility values, which are not preferred for clinical application. In summary, well-dispersed HAP nanofibers and their dental composites with enhanced mechanical properties have been successfully fabricated, but the water absorption and water solubility of such dental composites need to be further improved.
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Affiliation(s)
- Liang Chen
- Department of Mechanical and Aerospace Engineering, University of Missouri-Columbia, Columbia, MO 65211, USA
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Toledano M, Yamauti M, Osorio E, Monticelli F, Osorio R. Characterization of micro- and nanophase separation of dentin bonding agents by stereoscopy and atomic force microscopy. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2012; 18:279-288. [PMID: 22300801 DOI: 10.1017/s1431927611012621] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The aim was to study the effect of solvents on the phase separation of four commercial dental adhesives. Four materials were tested: Clearfil™ SE Bond (CSE), Clearfil Protect Bond (CPB), Clearfil S3 Bond (CS3), and One-Up Bond F Plus (OUB). Distilled water or ethanol was used as a solvent (30 vol%) for microphase separation studies, by stereoscopy. For nanophase images, the mixtures were formulated with two different solvent concentrations (2.5 versus 5 vol%) and observed by atomic force microscopy. Images were analyzed by using MacBiophotonics ImageJ to measure the area of bright domains. Macrophase separations, identified as a loss of clarity, were only observed after mixing the adhesives with water. Nanophase separations were detected with all adhesive combinations. The area of bright domains ranged from 132 to 1,145 nm² for CSE, from 15 to 285 nm² for CPB, from 149 to 380 nm² for CS3, and from 26 to 157 nm² for OUB. In water-resins mixtures, CPB was the most homogeneous and OUB showed the most heterogeneous phase formation. In ethanol-resin mixtures, CSE attained the most homogeneous structure and OUB showed the most heterogeneous phase. Addition of 5 vol% ethanol to resins decreased the nanophase separation when compared with the control materials.
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Affiliation(s)
- Manuel Toledano
- Materiales Dentales, Facultad de Odontología, Colegio Máximo, Campus de Cartuja sn, Universidad de Granada, Granada 18071, Spain.
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Ye Q, Park J, Parthasarathy R, Pamatmat F, Misra A, Laurence JS, Marangos O, Spencer P. Quantitative analysis of aqueous phase composition of model dentin adhesives experiencing phase separation. J Biomed Mater Res B Appl Biomater 2012; 100:1086-92. [PMID: 22331596 DOI: 10.1002/jbm.b.32675] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2011] [Revised: 12/18/2011] [Accepted: 12/22/2011] [Indexed: 11/05/2022]
Abstract
There have been reports of the sensitivity of our current dentin adhesives to excess moisture, for example, water-blisters in adhesives placed on over-wet surfaces, and phase separation with concomitant limited infiltration of the critical dimethacrylate component into the demineralized dentin matrix. To determine quantitatively the hydrophobic/hydrophilic components in the aqueous phase when exposed to over-wet environments, model adhesives were mixed with 16, 33, and 50 wt % water to yield well-separated phases. Based upon high-performance liquid chromatography coupled with photodiode array detection, it was found that the amounts of hydrophobic BisGMA and hydrophobic initiators are less than 0.1 wt % in the aqueous phase. The amount of these compounds decreased with an increase in the initial water content. The major components of the aqueous phase were hydroxyethyl methacrylate (HEMA) and water, and the HEMA content ranged from 18.3 to 14.7 wt %. Different BisGMA homologues and the relative content of these homologues in the aqueous phase have been identified; however, the amount of crosslinkable BisGMA was minimal and, thus, could not help in the formation of a crosslinked polymer network in the aqueous phase. Without the protection afforded by a strong crosslinked network, the poorly photoreactive compounds of this aqueous phase could be leached easily. These results suggest that adhesive formulations should be designed to include hydrophilic multimethacrylate monomers and water compatible initiators.
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Affiliation(s)
- Qiang Ye
- Bioengineering Research Center, University of Kansas, Lawrence, Kansas 66045-7609, USA.
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Spencer P, Jonggu Park QY, Misra A, Bohaty BS, Singh V, Parthasarathy R, Sene F, de Paiva Gonçalves SE, Laurence J. Durable bonds at the adhesive/dentin interface: an impossible mission or simply a moving target? BRAZILIAN DENTAL SCIENCE 2012; 15:4-18. [PMID: 24855586 PMCID: PMC4028112 DOI: 10.14295/bds.2012.v15i1.790] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/24/2023] Open
Abstract
Composite restorations have higher failure rates, more recurrent caries and increased frequency of replacement as compared to dental amalgam. Penetration of bacterial enzymes, oral fluids, and bacteria into the crevices between the tooth and composite undermines the restoration and leads to recurrent decay and failure. The gingival margin of composite restora tions is particularly vulnerable to decay and at this margin, the adhesive and its seal to dentin provides the primary barrier between the prepared tooth and the environment. The intent of this article is to examine physico-chemical factors that affect the integrity and durability of the adhesive/dentin interfacial bond; and to explore how these factors act synergistically with mechanical forces to undermine the composite restoration. The article will examine the various avenues that have been pursued to address these problems and it will explore how alterations in material chemistry could address the detrimental impact of physico-chemical stresses on the bond formed at the adhesive/dentin interface.
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Affiliation(s)
- Paulette Spencer
- Department of Mechanical Engineering - Bioengineering Research Center - University of Kansas - Lawrence - KS
| | | | - Anil Misra
- Bioengineering Research Center - Department of Civil Engineering - University of Kansas - Lawrence - KS
| | - Brenda S Bohaty
- Department of Pediatric Dentistry - University of Missouri - Kansas City - School of Dentistry - Kansas City - MO
| | - Viraj Singh
- Department of Mechanical Engineering - Bioengineering Research Center - University of Kansas - Lawrence - KS
| | | | - Fábio Sene
- Department of Restorative Dentistry - State University of Londrina - School of Dentistry - Londrina - Brazil
| | - Sérgio Eduardo de Paiva Gonçalves
- Department of Restorative Dentistry - School of Dentistry of São José dos Campos - UNESP - Univ Estadual Paulista - São José dos Campos - SP - Brazil
| | - Jennifer Laurence
- Department of Pharmaceutical Chemistry - University of Kansas - Lawrence - KS
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Park J, Ye Q, Singh V, Kieweg SL, Misra A, Spencer P. Synthesis and evaluation of novel dental monomer with branched aromatic carboxylic acid group. J Biomed Mater Res B Appl Biomater 2011; 100:569-76. [PMID: 22114017 DOI: 10.1002/jbm.b.31987] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 09/01/2011] [Accepted: 09/20/2011] [Indexed: 11/06/2022]
Abstract
A new glycerol-based dimethacrylate monomer with an aromatic carboxylic acid, 2-((1,3-bis(methacryloyloxy)propan-2-yloxy)carbonyl)benzoic acid (BMPB), was synthesized, characterized, and proposed as a possible dental co-monomer for dentin adhesives. Dentin adhesives containing 2-hydroxyethyl methacrylate (HEMA) and 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy) phenyl]propane (BisGMA) in addition to BMPB were formulated with water at 0, 5, 10, and 15 wt % to simulate wet, oral conditions, and photo-polymerized. Adhesives were characterized with regard to viscosity, real-time photopolymerization behavior, dynamic mechanical analysis, and microscale 3D internal morphologies and compared with HEMA/BisGMA controls. When formulated under wet conditions, the experimental adhesives showed lower viscosities (0.04-0.07 Pa s) as compared to the control (0.09-0.12 Pa s). The experimental adhesives showed higher glass transition temperature (146-157°C), degree of conversion (78-89%), and rubbery moduli (33-36 MPa), and improved water miscibility (no voids) as compared to the controls (123-135°C, 67-71%, 15-26 MPa, and voids, respectively). The enhanced properties of these adhesives suggest that BMPB with simple, straightforward synthesis is a promising photocurable co-monomer for dental restorative materials.
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Affiliation(s)
- Jonggu Park
- Bioengineering Research Center, School of Engineering, University of Kansas, Lawrence, Kansas
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Mazzoni A, Carrilho M, Papa V, Tjäderhane L, Gobbi P, Nucci C, Di Lenarda R, Mazzotti G, Tay FR, Pashley DH, Breschi L. MMP-2 assay within the hybrid layer created by a two-step etch-and-rinse adhesive: Biochemical and immunohistochemical analysis. J Dent 2011; 39:470-7. [DOI: 10.1016/j.jdent.2011.04.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 01/10/2011] [Accepted: 04/15/2011] [Indexed: 11/25/2022] Open
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Van Landuyt K, De Munck J, Mine A, Cardoso M, Peumans M, Van Meerbeek B. Filler Debonding & Subhybrid-layer Failures in Self-etch Adhesives. J Dent Res 2010; 89:1045-50. [PMID: 20631093 DOI: 10.1177/0022034510375285] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The mechanisms behind bond degradation are still largely unknown, in particular with respect to self-etch adhesives. One-step adhesives have been especially documented with problems, such as insufficient polymerization, water-uptake and subsequent plasticization, water- and enzyme-induced nanoleakage, and/or the presence of voids due to phase-separation or osmosis. It was hypothesized that these shortcomings may weaken the adhesive layer and, as such, may jeopardize long-term bonding. In contrast to the control three-step etch & rinse adhesive, the bond strength to dentin of both one-step and two-step self-etch adhesives decreased after six-month water storage. TEM revealed not only that they exhibited filler de-bonding within the adhesive resin layer, due to hydrolysis of the filler-matrix coupling, but also that they failed predominantly directly under the hybrid layer at dentin, in spite of the presence of interfacial droplets and nanoleakage in the adhesive layer. These failures just under the hybrid layer may be attributed to insufficient encapsulation of surface smear.
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Affiliation(s)
- K.L. Van Landuyt
- Leuven BIOMAT Research Cluster, Department of Conservative Dentistry, School of Dentistry, Oral Pathology and Maxillo-Facial Surgery, Catholic University of Leuven, Kapucijnenvoer 7, B-3000 Leuven, Belgium
| | - J. De Munck
- Leuven BIOMAT Research Cluster, Department of Conservative Dentistry, School of Dentistry, Oral Pathology and Maxillo-Facial Surgery, Catholic University of Leuven, Kapucijnenvoer 7, B-3000 Leuven, Belgium
| | - A. Mine
- Leuven BIOMAT Research Cluster, Department of Conservative Dentistry, School of Dentistry, Oral Pathology and Maxillo-Facial Surgery, Catholic University of Leuven, Kapucijnenvoer 7, B-3000 Leuven, Belgium
| | - M.V. Cardoso
- Leuven BIOMAT Research Cluster, Department of Conservative Dentistry, School of Dentistry, Oral Pathology and Maxillo-Facial Surgery, Catholic University of Leuven, Kapucijnenvoer 7, B-3000 Leuven, Belgium
| | - M. Peumans
- Leuven BIOMAT Research Cluster, Department of Conservative Dentistry, School of Dentistry, Oral Pathology and Maxillo-Facial Surgery, Catholic University of Leuven, Kapucijnenvoer 7, B-3000 Leuven, Belgium
| | - B. Van Meerbeek
- Leuven BIOMAT Research Cluster, Department of Conservative Dentistry, School of Dentistry, Oral Pathology and Maxillo-Facial Surgery, Catholic University of Leuven, Kapucijnenvoer 7, B-3000 Leuven, Belgium
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Park J, Ye Q, Topp EM, Misra A, Kieweg SL, Spencer P. Effect of photoinitiator system and water content on dynamic mechanical properties of a light-cured bisGMA/HEMA dental resin. J Biomed Mater Res A 2010; 93:1245-51. [PMID: 19827107 PMCID: PMC2860647 DOI: 10.1002/jbm.a.32617] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The selection of an appropriate photoinitiator system is critical for efficient polymerization of dental resins with satisfactory mechanical and physical properties. The purpose of this study was to evaluate the influence of adding an iodonium salt to two-component photoinitiator systems. Four photoinitiator systems were included in a model bisGMA/HEMA resin and used to prepare samples at different water contents; the dynamic mechanical properties and the final degree of conversion of the samples were then characterized. Addition of the iodonium salt to the two-component photoinitiator systems increased the final degree of conversion, glass transition temperature, rubbery modulus, and crosslink density. The photoinitiator system containing ethyl-4-(dimethylamino) benzoate as a coinitiator and the iodonium salt exhibited the highest rubbery modulus. The enhanced properties in the presence of the iodonium salt can be attributed to the production of an active phenyl radical with regeneration of the original camphorquinone, which may increase the compatibility between monomers and initiators, especially in the presence of water. The results support the hypothesis that a photoinitiator system containing an iodonium salt can increase both mechanical properties and final conversion of model resin polymerized in the presence of water.
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Affiliation(s)
- Jonggu Park
- Bioengineering Research Center, University of Kansas, Lawrence, KS, USA
| | - Qiang Ye
- Bioengineering Research Center, University of Kansas, Lawrence, KS, USA
| | - Elizabeth M. Topp
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, USA
| | - Anil Misra
- Bioengineering Research Center, University of Kansas, Lawrence, KS, USA
- Department of Civil, Environmental and Architectural Engineering, University of Kansas, Lawrence, KS, USA
| | - Sarah L. Kieweg
- Department of Mechanical Engineering, University of Kansas, Lawrence, KS, USA
| | - Paulette Spencer
- Bioengineering Research Center, University of Kansas, Lawrence, KS, USA
- Department of Mechanical Engineering, University of Kansas, Lawrence, KS, USA
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Spencer P, Ye Q, Park J, Topp EM, Misra A, Marangos O, Wang Y, Bohaty BS, Singh V, Sene F, Eslick J, Camarda K, Katz JL. Adhesive/Dentin interface: the weak link in the composite restoration. Ann Biomed Eng 2010; 38:1989-2003. [PMID: 20195761 PMCID: PMC2871971 DOI: 10.1007/s10439-010-9969-6] [Citation(s) in RCA: 294] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2010] [Accepted: 02/12/2010] [Indexed: 11/30/2022]
Abstract
Results from clinical studies suggest that more than half of the 166 million dental restorations that were placed in the United States in 2005 were replacements for failed restorations. This emphasis on replacement therapy is expected to grow as dentists use composite as opposed to dental amalgam to restore moderate to large posterior lesions. Composite restorations have higher failure rates, more recurrent caries, and increased frequency of replacement as compared to amalgam. Penetration of bacterial enzymes, oral fluids, and bacteria into the crevices between the tooth and composite undermines the restoration and leads to recurrent decay and premature failure. Under in vivo conditions the bond formed at the adhesive/dentin interface can be the first defense against these noxious, damaging substances. The intent of this article is to review structural aspects of the clinical substrate that impact bond formation at the adhesive/dentin interface; to examine physico-chemical factors that affect the integrity and durability of the adhesive/dentin interfacial bond; and to explore how these factors act synergistically with mechanical forces to undermine the composite restoration. The article will examine the various avenues that have been pursued to address these problems and it will explore how alterations in material chemistry could address the detrimental impact of physico-chemical stresses on the bond formed at the adhesive/dentin interface.
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Affiliation(s)
- Paulette Spencer
- Department of Mechanical Engineering, University of Kansas, 1530 W 15th St, Lawrence, KS 66045, USA.
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Souza ROA, Ozcan M, Michida SMA, de Melo RM, Pavanelli CA, Bottino MA, Soares LES, Martin AA. Conversion degree of indirect resin composites and effect of thermocycling on their physical properties. J Prosthodont 2009; 19:218-25. [PMID: 20040031 DOI: 10.1111/j.1532-849x.2009.00551.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
PURPOSE This study evaluated the degree of conversion (DC) of four indirect resin composites (IRCs) with various compositions processed in different polymerization units and investigated the effect of thermal aging on the flexural strength and Vicker's microhardness. MATERIALS AND METHODS Specimens were prepared from four IRC materials, namely Gr 1: Resilab (Wilcos); Gr2: Sinfony (3M ESPE); Gr3: VITA VMLC (VITA Zahnfabrik); Gr4: VITA Zeta (VITA Zahnfabrik) using special molds for flexural strength test (N = 80, n = 10 per group) (25 x 2 x 2 mm(3), ISO 4049), for Vicker's microhardness test (N = 80, n = 10 per group) (5 x 4 mm(2)) and for DC (N = 10) using FT-Raman Spectroscopy. For both flexural strength and microhardness tests, half of the specimens were randomly stored in distilled water at 37 degrees C for 24 hours (Groups 1 to 4), and the other half (Groups 5 to 8) were subjected to thermocycling (5000 cycles, 5 to 55 +/- 1 degree C, dwell time: 30 seconds). Flexural strength was measured in a universal testing machine (crosshead speed: 0.8 mm/min). Microhardness test was performed at 50 g. The data were analyzed using one-way and two-way ANOVA and Tukey's test (alpha= 0.05). The correlation between flexural strength and microhardness was evaluated with Pearson's correlation test (alpha= 0.05). RESULTS A significant effect for the type of IRC and thermocycling was found (p= 0.001, p= 0.001) on the flexural strength results, but thermocycling did not significantly affect the microhardness results (p= 0.078). The interaction factors were significant for both flexural strength and microhardness parameters (p= 0.001 and 0.002, respectively). Thermocycling decreased the flexural strength of the three IRCs tested significantly (p < 0.05), except for VITA Zeta (106.3 +/- 9.1 to 97.2 +/- 14 MPa) (p > 0.05) when compared with nonthermocycled groups. Microhardness results of only Sinfony were significantly affected by thermocycling (25.1 +/- 2.1 to 31 +/- 3.3 Kg/mm(2)). DC values ranged between 63% and 81%, and were not significantly different between the IRCs (p > 0.05). While a positive correlation was found between flexural strength and microhardness without (r = 0.309) and with thermocycling (r = 0.100) for VITA VMLC, negative correlations were found for Resilab under the same conditions (r =-0.190 and -0.305, respectively) (Pearson's correlation coefficient). CONCLUSION Although all four IRCs presented nonsignificant DC values, flexural strength and microhardness values varied between materials with and without thermocycling.
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Affiliation(s)
- Rodrigo O A Souza
- Department of Dental Materials and Prosthodontics, São Jose dos Campos Dental School, São Paulo State University, São Jose dos Campos, Brazil
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Park JG, Ye Q, Topp EM, Spencer P. Enzyme-catalyzed hydrolysis of dentin adhesives containing a new urethane-based trimethacrylate monomer. J Biomed Mater Res B Appl Biomater 2009; 91:562-571. [PMID: 19582843 PMCID: PMC2758931 DOI: 10.1002/jbm.b.31430] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A new trimethacrylate monomer with urethane-linked groups, 1,1,1-tri-[4-(methacryloxyethylamino-carbonyloxy)-phenyl]ethane (MPE), was synthesized, characterized, and used as a comonomer in dentin adhesives. Dentin adhesives containing 2-hydroxyethyl methacrylate (HEMA, 45% w/w) and 2,2-bis[4(2-hydroxy-3-methacryloyloxy-propyloxy)-phenyl] propane (BisGMA, 30% w/w) in addition to MPE (25% w/w) were formulated with H(2)O at 0 (MPE0), 8 (MPE8), and 16 wt % water (MPE16) to simulate the wet demineralized dentin matrix and compared with controls [HEMA /BisGMA, 45/55 w/w, at 0 (C0), 8 (C8), and 16 wt % water (C16)]. The new adhesive showed a degree of double bond conversion and mechanical properties comparable with control, with good penetration into the dentin surface and a uniform adhesive/dentin interface. On exposure to porcine liver esterase, the net cumulative methacrylic acid (MAA) released from the new adhesives was dramatically (p < 0.05) decreased relative to the control, suggesting that the new monomer improves esterase resistance.
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Affiliation(s)
- Jong-Gu Park
- Bioengineering Research Center, School of Engineering, University of Kansas, Lawrence, KS, 66045
| | - Qiang Ye
- Bioengineering Research Center, School of Engineering, University of Kansas, Lawrence, KS, 66045
| | - Elizabeth M. Topp
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Kansas, Lawrence, KS 66047
| | - Paulette Spencer
- Bioengineering Research Center, School of Engineering, University of Kansas, Lawrence, KS, 66045,Department of Mechanical Engineering, University of Kansas, Lawrence, KS, 66045, Address all correspondence to Dr. Paulette Spencer. Tel.: +1 785 864 8140; fax: 1 785 864 5254;
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Park JG, Ye Q, Topp EM, Lee CH, Kostoryz EL, Misra A, Spencer P. Dynamic mechanical analysis and esterase degradation of dentin adhesives containing a branched methacrylate. J Biomed Mater Res B Appl Biomater 2009; 91:61-70. [PMID: 19358261 PMCID: PMC2990471 DOI: 10.1002/jbm.b.31374] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A study of the dynamic mechanical properties and the enzymatic degradation of new dentin adhesives containing a multifunctional methacrylate are described. Adhesives contained 2-hydroxyethyl methacrylate, 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy) phenyl]-propane, and a new multifunctional methacrylate with a branched side chain-trimethylolpropane mono allyl ether dimethacrylate (TMPEDMA). Adhesives were photopolymerized in the presence of 0, 8, and 16 wt % water to simulate wet bonding conditions in the mouth and compared with control adhesives. The degree of conversion as a function of irradiation time was comparable for experimental and control adhesives. In dynamic mechanical analysis, broad tan delta peaks were obtained for all samples, indicating that the polymerized networks are heterogeneous; comparison of the full-width-at-half-maximum values obtained from the tan delta curves indicated increased heterogeneity for samples cured in the presence of water and/or containing TMPEDMA. The experimental adhesive showed higher T(g) and higher rubbery modulus indicating increased crosslink density when compared with the control. The improvement in esterase resistance afforded by adhesives containing the TMPEDMA is greater when this material is photopolymerized in the presence of water, suggesting better performance in the moist environment of the mouth. The improved esterase resistance of the new adhesive could be explained in terms of the densely crosslinked network structure and/or the steric hindrance of branched alkyl side chains.
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Affiliation(s)
- Jong-Gu Park
- Bioengineering Research Center, University of Kansas, Lawrence, Kansas, USA
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Kostoryz EL, Dharmala K, Ye Q, Wang Y, Huber J, Park JG, Snider G, Katz JL, Spencer P. Enzymatic biodegradation of HEMA/bisGMA adhesives formulated with different water content. J Biomed Mater Res B Appl Biomater 2009; 88:394-401. [PMID: 18395826 PMCID: PMC2656768 DOI: 10.1002/jbm.b.31095] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Dentin adhesives may undergo phase separation when bonding to wet demineralized dentin. We hypothesized that adhesives exhibiting phase separation will experience enhanced biodegradation of methacrylate ester groups. The objective of this project was to study the effect of enzyme-exposure on the release of methacrylic acid (MAA) and 2-hydroxyethyl methacrylate (HEMA) from adhesives formulated under conditions simulating wet bonding. HEMA/bisGMA(2,2-bis[4(2-hydroxy-3-methacryloyloxy-propyloxy)-phenyl] propane), 45/55 w/w ratio, was formulated with different water content: 0 Wt % (A00), 8 wt % (A08), and 16 wt % (A16). After a three day prewash, adhesive discs were incubated with/without porcine liver esterase (PLE) in phosphate buffer (PB, pH 7.4) at 37 degrees C for 8 days. Supernatants were collected daily and analyzed for MAA and HEMA by HPLC. For all formulations, daily MAA release in the presence of PLE was increased compared to MAA release in PB. HEMA release in the presence of PLE was not detected while HEMA release was consistently measured in PB. A08 and A16 released significantly larger amounts of HEMA compared to A00. Analysis of the cumulative release of analytes showed that the leachables in PLE was significantly increased (p < 0.05) as compared with that released in PB indicating that MAA release was not only formed from unreacted monomers but from pendant groups in the polymer network. However, the levels of analytes HEMA in PB or MAA in PLE were increased in A08 and A16 as compared with A00, which suggests that there could be a greater loss of material in HEMA/bisGMA adhesives that experience phase separation under wet bonding conditions.
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Affiliation(s)
- Elisabet L Kostoryz
- Pharmacology & Toxicology Division, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri, USA
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Ye Q, Wang Y, Spencer P. Nanophase separation of polymers exposed to simulated bonding conditions. J Biomed Mater Res B Appl Biomater 2009; 88:339-48. [DOI: 10.1002/jbm.b.31047] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Miletic VJ, Santini A. Remaining unreacted methacrylate groups in resin-based composite with respect to sample preparation and storing conditions using micro-Raman spectroscopy. J Biomed Mater Res B Appl Biomater 2008; 87:468-74. [DOI: 10.1002/jbm.b.31128] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Ye Q, Park JG, Topp E, Wang Y, Misra A, Spencer P. In vitro performance of nano-heterogeneous dentin adhesive. J Dent Res 2008; 87:829-33. [PMID: 18719208 DOI: 10.1177/154405910808700911] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Water is ubiquitous in the mouths of healthy individuals and routinely interferes with efforts to bond restorations to dental tissues. Our previous studies using tapping-mode atomic force microscopy (TMAFM) have shown that nanophase separation is a general feature of cross-linked polymethacrylates photocured in the presence of water. To explore the relationship between nanophase separation in dentin adhesives and their long-term mechanical properties, we evaluated model adhesives after 3 months of aqueous storage. The degree of contrast in the TMAFM phase image depended on the formulations used, ranging from 'not observable' to 'very strong'. Correspondingly, the mechanical properties of these model adhesives varied from 'minimal change' to 'significant depreciation'. The results support the hypothesis that a high degree of heterogeneity at the nano-scale is associated with poor mechanical durability in these model adhesives.
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Affiliation(s)
- Q Ye
- Bioengineering Research Center, University of Kansas, 1530 W. 15th Street, Lawrence, KS 66045, USA
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Cavalcanti AN, Mitsui FHO, Silva F, Peris AR, Bedran-Russo A, Marchi GM. Effect of Cyclic Loading on the Bond Strength of Class II Restorations with Different Composite Materials. Oper Dent 2008; 33:163-8. [PMID: 18435190 DOI: 10.2341/07-65] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Clinical Relevance
New resin composite technologies, such as nano-filled-based systems, have been developed. The assessment of such materials in a simulated laboratory chewing condition may assist with the selection of composites in a clinical situation.
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Affiliation(s)
- Andrea Nóbrega Cavalcanti
- Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil.
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Ye Q, Wang Y, Williams K, Spencer P. Characterization of photopolymerization of dentin adhesives as a function of light source and irradiance. J Biomed Mater Res B Appl Biomater 2007; 80:440-6. [PMID: 16850459 PMCID: PMC1995012 DOI: 10.1002/jbm.b.30615] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Manufacturers have attempted to address the limitations associated with dentin bonding by eliminating as many steps as possible in the bonding protocol. Theoretically, this approach increases the efficiency of the procedure and reduces technique sensitivity. These trends are reflected in the introduction of all-in one, single-step adhesive systems; the increased concentration of acidic resin monomers in these systems allows for simultaneous etching and priming of the prepared dentin surface. Ideally, the degree of monomer conversion would be high enough that the acidic reaction would be self-limiting. The purpose of this study was to investigate the effect of light irradiance and source on the photopolymerization of three commercial dental adhesives by monitoring the double bond conversion as a function of time during and after irradiation. The photopolymerization curing efficiency of the commercial adhesives investigated in this study varied as a function of light source and distance. The use of LED performed better than the halogen light in terms of polymerization rate and degree of conversion for the commercial single-step, sixth generation adhesive, Adper Prompt. In contrast, polymerization of commercial single-bottle, fifth generation adhesive, Single Bond and One-Up Bond F, was mainly a function of exposure time, irrespective of the two light units or intensities.
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Affiliation(s)
- Qiang Ye
- Department of Oral Biology, University of Missouri-Kansas City School of Dentistry, Kansas City, Missouri 64108, USA
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Ye Q, Spencer P, Wang Y, Misra A. Relationship of solvent to the photopolymerization process, properties, and structure in model dentin adhesives. J Biomed Mater Res A 2007; 80:342-50. [PMID: 17001655 PMCID: PMC2566510 DOI: 10.1002/jbm.a.30890] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The ratio of the double-bond content of monomer to polymer, i.e. degree of conversion (DC) has been used frequently as a convenient means of comparing the behavior and properties of dental composites and adhesives. The purpose of this investigation was to study the relationship of photopolymerization processes, bulk properties, and structure using model dentin adhesives cured in the presence of different ethanol content as an example. There was little difference in the DC of model BisGMA-based adhesives cured in the presence of ethanol concentrations ranging from 0 to 40 wt %, but there were substantial differences in the mechanical properties. Ultimate tensile strength (UTS) and modulus of elasticity decreased with an increase in ethanol content. Polymer structure was revealed by thermal behavior in the glass transition temperature (Tg) region; these measurements were obtained by modulated temperature differential scanning calorimetry (MTDSC) technology, which removes the competing irreversible effects associated with release of volatiles and residual curing. Glass transition temperature of model adhesives decreased substantially with an increase in ethanol content. The DC based on the quantity of remaining double bond has been used extensively to characterize and provide a relative assessment of the quality of dentin adhesives and dental composites. Since polymers differing in linearity, and therefore crosslink density, may have a similar degree of conversion, the measurement of monomer/polymer conversion does not necessarily provide complete representation of the quality or durability of the polymer structure.
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Affiliation(s)
- Qiang Ye
- Department of Oral Biology, University of Missouri-Kansas City School of Dentistry, 650 E. 25th St., Kansas City, Missouri 64108, USA
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