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Dumur F. The Future of Visible Light Photoinitiators of Polymerization for Photocrosslinking Applications. Eur Polym J 2023. [DOI: 10.1016/j.eurpolymj.2023.111883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
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Wang Q, Wellinghoff ST, Rawls HR. Investigation of Thermal-Induced Changes in Molecular Order on Photopolymerization and Performance Properties of a Nematic Liquid-Crystal Diacrylate. MATERIALS (BASEL, SWITZERLAND) 2022; 15:4605. [PMID: 35806735 PMCID: PMC9267439 DOI: 10.3390/ma15134605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 06/25/2022] [Accepted: 06/28/2022] [Indexed: 02/05/2023]
Abstract
Polymerization shrinkage and associated stresses are the main reasons for dental restorative failure. We developed a series of liquid crystal diacrylates and dimethacrylates which have markedly low polymerization shrinkage. In order to fully understand the effects of temperature-induced changes of molecular order on the photopolymerization process and performance properties of the generated polymers, the photopolymerization of a difunctional acrylate, 2-t-butyl-1,4-phenylene bis (4-(6-(acryloyloxy)hexyloxy)benzoate), which exists in the nematic liquid crystalline phase at room temperature, was investigated as a function of photopolymerization temperature over the nematic to isotropic range. Morphological studies suggested that a mesogenic phase was immediately formed in the polymer even if polymerization in thin films occurred above the nematic-to-isotropic (N→I) transition temperature of the monomer (Tn-i = 45.8 °C). Dynamic mechanical analysis of 2 × 2 mm cross-section bar samples polymerized at 60 °C showed reduced elastic moduli, increased glass transition temperature and formation of a more crosslinked network, in comparison to polymers formed at lower polymerization temperatures. Fractography analysis showed that polymers generated from the nematic liquid crystalline phase underwent a different fracture pattern in comparison to those generated from the isotropic phase. Volumetric shrinkage (2.2%) found in polymer polymerized from the nematic liquid crystalline phase at room temperature was substantially less than the 6.0% observed in polymer polymerized from an initial isotropic phase at 60 °C, indicating that an organized monomer can greatly contribute to reducing cure shrinkage.
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Affiliation(s)
- Qian Wang
- Division of Research, Department of Comprehensive Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA;
- Core Facility Center for Life Sciences, University of Science and Technology of China, Hefei 230026, China
| | - Stephen T. Wellinghoff
- Chemistry and Chemical Engineering Division, Southwest Research Institute, San Antonio, TX 78238, USA;
| | - Henry Ralph Rawls
- Division of Research, Department of Comprehensive Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA;
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Plyusnin A, He J, Elschner C, Nakamura M, Kulkova J, Spickenheuer A, Scheffler C, Lassila LVJ, Moritz N. A Polymer for Application as a Matrix Phase in a Concept of In Situ Curable Bioresorbable Bioactive Load-Bearing Continuous Fiber Reinforced Composite Fracture Fixation Plates. Molecules 2021; 26:molecules26051256. [PMID: 33652632 PMCID: PMC7956420 DOI: 10.3390/molecules26051256] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/22/2021] [Accepted: 02/23/2021] [Indexed: 12/04/2022] Open
Abstract
The use of bioresorbable fracture fixation plates made of aliphatic polyesters have good potential due to good biocompatibility, reduced risk of stress-shielding, and eliminated need for plate removal. However, polyesters are ductile, and their handling properties are limited. We suggested an alternative, PLAMA (PolyLActide functionalized with diMethAcrylate), for the use as the matrix phase for the novel concept of the in situ curable bioresorbable load-bearing composite plate to reduce the limitations of conventional polyesters. The purpose was to obtain a preliminary understanding of the chemical and physical properties and the biological safety of PLAMA from the prospective of the novel concept. Modifications with different molecular masses (PLAMA-500 and PLAMA-1000) were synthesized. The efficiency of curing was assessed by the degree of convergence (DC). The mechanical properties were obtained by tensile test and thermomechanical analysis. The bioresorbability was investigated by immersion in simulated body fluid. The biocompatibility was studied in cell morphology and viability tests. PLAMA-500 showed better DC and mechanical properties, and slower bioresorbability than PLAMA-1000. Both did not prevent proliferation and normal morphological development of cells. We concluded that PLAMA-500 has potential for the use as the matrix material for bioresorbable load-bearing composite fracture fixation plates.
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Affiliation(s)
- Artem Plyusnin
- Turku Clinical Biomaterials Centre—TCBC, Department of Biomaterials Science, Faculty of Medicine, Institute of Dentistry, University of Turku, FI-20014 Turku, Finland; (A.P.); (L.V.J.L.); (N.M.)
| | - Jingwei He
- College of Materials Science and Engineering, South China University of Technology, Guangzhou 510006, China;
| | - Cindy Elschner
- Leibniz-Institut für Polymerforschung Dresden e. V., D-01005 Dresden, Germany; (C.E.); (A.S.); (C.S.)
| | - Miho Nakamura
- Medicity Research Laboratory, Faculty of Medicine, University of Turku, FI-20014 Turku, Finland;
| | - Julia Kulkova
- Turku Clinical Biomaterials Centre—TCBC, Department of Biomaterials Science, Faculty of Medicine, Institute of Dentistry, University of Turku, FI-20014 Turku, Finland; (A.P.); (L.V.J.L.); (N.M.)
- Correspondence: ; Tel.: +358-44-974-91-83
| | - Axel Spickenheuer
- Leibniz-Institut für Polymerforschung Dresden e. V., D-01005 Dresden, Germany; (C.E.); (A.S.); (C.S.)
| | - Christina Scheffler
- Leibniz-Institut für Polymerforschung Dresden e. V., D-01005 Dresden, Germany; (C.E.); (A.S.); (C.S.)
| | - Lippo V. J. Lassila
- Turku Clinical Biomaterials Centre—TCBC, Department of Biomaterials Science, Faculty of Medicine, Institute of Dentistry, University of Turku, FI-20014 Turku, Finland; (A.P.); (L.V.J.L.); (N.M.)
| | - Niko Moritz
- Turku Clinical Biomaterials Centre—TCBC, Department of Biomaterials Science, Faculty of Medicine, Institute of Dentistry, University of Turku, FI-20014 Turku, Finland; (A.P.); (L.V.J.L.); (N.M.)
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Influence of the Postcuring Process on Dimensional Accuracy and Seating of 3D-Printed Polymeric Fixed Prostheses. BIOMED RESEARCH INTERNATIONAL 2020; 2020:2150182. [PMID: 33274198 PMCID: PMC7683121 DOI: 10.1155/2020/2150182] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 09/17/2020] [Accepted: 11/09/2020] [Indexed: 11/30/2022]
Abstract
The postcuring process is essential for 3-dimensional (3D) printing of photopolymer-based dental prostheses. However, the deformation of prostheses resulting from the postcuring process has not been fully investigated. The purpose of this study was to evaluate the effects of different postcuring methods on the fit and dimensional accuracy of 3D-printed full-arch polymeric fixed prostheses. A study stone model with four prosthetic implant abutments was prepared. A full-arch fixed dental prosthesis was designed, and the design was transferred to dental computer-aided manufacturing (CAM) software in which supports were designed to the surface of the prosthesis design for 3D printing. Using a biocompatible photopolymer and a stereolithography apparatus 3D printer, polymeric prostheses were produced (N = 21). In postcuring, the printed prostheses were polymerized in three different ways: the prosthesis alone, the prosthesis with supports, or the prosthesis on a stone model. Geometric accuracy of 3D-printed prostheses, marginal gap, internal gap, and intermolar distance was evaluated using microscopy and digital techniques. Kruskal-Wallis and Mann-Whitney U tests with Bonferroni correction were used for the comparison of results among groups (α = 0.05). In general, the mean marginal and internal gaps of cured prostheses were the smallest when the printed prostheses were cured with seating on the stone model (P < 0.05). With regard to the adaptation accuracy, the presence of supports during the postcuring process did not make a significant difference. Error in the intermolar distance was significantly smaller in the model seating condition than in the other conditions (P < 0.001). Seating 3D-printed prosthesis on the stone model reduces adverse deformation in the postcuring process, thereby enabling the fabrication of prostheses with favorable adaptation.
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Huang YJ, Chou YN, Lin YJ, Chen WY, Chen CY, Lin HR. Polyurethane modified by oxetane grafted chitosan as bioadhesive. INT J POLYM MATER PO 2020. [DOI: 10.1080/00914037.2020.1785453] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Yi-Jing Huang
- Department of Chemical and Materials Engineering, Southern Taiwan University of Science and Technology, Tainan, Taiwan
| | - Ying-Nien Chou
- Department of Chemical and Materials Engineering, Southern Taiwan University of Science and Technology, Tainan, Taiwan
| | - Yiu-Jiuan Lin
- Department of Nursing, Chung Hwa University of Medical Technology, Tainan, Taiwan
| | - Wei-Yu Chen
- Department of Chemical and Materials Engineering, Southern Taiwan University of Science and Technology, Tainan, Taiwan
| | - Chuh-Yean Chen
- Department of Chemical and Materials Engineering, Southern Taiwan University of Science and Technology, Tainan, Taiwan
| | - Hong-Ru Lin
- Department of Chemical and Materials Engineering, Southern Taiwan University of Science and Technology, Tainan, Taiwan
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Dressano D, Salvador MV, Oliveira MT, Marchi GM, Fronza BM, Hadis M, Palin WM, Lima AF. Chemistry of novel and contemporary resin-based dental adhesives. J Mech Behav Biomed Mater 2020; 110:103875. [PMID: 32957185 DOI: 10.1016/j.jmbbm.2020.103875] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 05/12/2020] [Accepted: 05/20/2020] [Indexed: 12/23/2022]
Abstract
The chemistry of resin-based dental adhesives is critical for its interaction with dental tissues and long-term bonding stability. Changes in dental adhesives composition influences the materials' key physical-chemical properties, such as rate and degree of conversion, water sorption, solubility, flexural strength and modulus, and cohesive strength and improves the biocompatibility to dental tissues. Maintaining a suitable reactivity between photoinitiators and monomers is important for optimal properties of adhesive systems, in order to enable adequate polymerisation and improved chemical, physical and biological properties. The aim of this article is to review the current state-of-the-art of dental adhesives, and their chemical composition and characteristics that influences the polymerisation reaction and subsequent materials properties and performance.
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Affiliation(s)
- Diogo Dressano
- Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Av Limeira, 901 Mail Box 52, Piracicaba, Sao Paulo, 13414-903, Brazil.
| | - Marcos V Salvador
- Dental Research Division, Paulista University, Sao Paulo, Rua Doutor Bacelar, 1212, CEP: 04026-002, Brazil.
| | | | - Giselle Maria Marchi
- Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Av Limeira, 901 Mail Box 52, Piracicaba, Sao Paulo, 13414-903, Brazil.
| | - Bruna M Fronza
- Department of Biomaterials and Oral Biology, University of São Paulo, 2227 Prof. Lineu Prestes Ave, 05508-000, São Paulo, SP, Brazil.
| | - Mohammed Hadis
- Dental Materials Science, Birmingham Dental School and Hospital, College of Medical and Dental Science, University of Birmingham, 5 Mill Pool Way, Edgbaston, Birmingham, B5 7EG, UK.
| | - William M Palin
- Dental Materials Science, Birmingham Dental School and Hospital, College of Medical and Dental Science, University of Birmingham, 5 Mill Pool Way, Edgbaston, Birmingham, B5 7EG, UK.
| | - Adriano Fonseca Lima
- Dental Research Division, Paulista University, Sao Paulo, Rua Doutor Bacelar, 1212, CEP: 04026-002, Brazil.
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Ferrelli GL, Kim HI, Zaldivar RJ. Effect of photoinitiator concentration on hygroscopic stability of UV cured precision replicated composite optics. APPLIED OPTICS 2020; 59:4606-4617. [PMID: 32543569 DOI: 10.1364/ao.388578] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 04/22/2020] [Indexed: 06/11/2023]
Abstract
Replicated composite optics is a promising technique to fabricate high-quality mirrors with reduced weight and processing time compared to conventional glass mirrors; however, the optical layer is organic and susceptible to environmentally-induced dimensional changes, specifically to moisture exposures. Generally, to enhance polymer stability, thermal curing is necessary to maximize the cure state. Because replications are bonded, thermal exposures generate residual stresses that degrade optical quality. In this paper, the cure state of a UV-cured epoxy with RT processing was varied by changing the photoinitiator (PI) concentration, and the replication stability was evaluated in different humidity environments by laser interferometry. Increasing the PI concentration transformed the epoxy microstructure from homogenous to a more phasic network, as evidenced by both DMA and AFM, resulting in significant changes to the Tg, modulus, and moisture absorption. When replications were exposed to moisture, they experienced initial swelling followed by stress relaxation to net-zero regardless of initial processing stress. Reduced PI concentrations exhibited higher moduli and shorter swelling periods, with dimensional changes as small as 35 nm and complete stress relaxation in days. TTS master curves describing stress relaxation behavior correlated well with the observed behavior in replicated mirror samples. Furthermore, it was shown that the relieved stress persisted through multiple humidity cycles between 100% to 0% RH. These results show that high-humidity conditioning treatments can be utilized to eliminate residual stress in as-fabricated replicated mirrors over just a few days, providing a viable manufacturing and processing route for highly precise and stable replicated composite mirrors.
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Shete AU, Sutherland BP, Kloxin CJ. One-component rapid Norrish Type II photoinitiation of bulk photo-CuAAC polymer networks. Polym Chem 2020. [DOI: 10.1039/d0py01310b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A one-component photoinitiation scheme was devised utilizing amine-centered trialkyne monomers for the formation of bulk photo-CuAAC polymer networks. The novel monomers maintain rapid polymerization kinetics and allow for tuning of the Tg.
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Affiliation(s)
- Abhishek U. Shete
- Department of Material Science and Engineering
- University of Delaware
- Newark
- USA
| | - Bryan P. Sutherland
- Department of Material Science and Engineering
- University of Delaware
- Newark
- USA
| | - Christopher J. Kloxin
- Department of Material Science and Engineering
- University of Delaware
- Newark
- USA
- Department of Chemical and Biomolecular Engineering
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Pérez-Mondragón AA, Cuevas-Suárez CE, Suárez Castillo OR, González-López JA, Herrera-González AM. Evaluation of biocompatible monomers as substitutes for TEGDMA in resin-based dental composites. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2018; 93:80-87. [PMID: 30274114 DOI: 10.1016/j.msec.2018.07.059] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Revised: 07/09/2018] [Accepted: 07/22/2018] [Indexed: 10/28/2022]
Abstract
This works reports the synthesis and characterization of diallyl(5-(hydroxymethyl)-1,3-phenylene) dicarbonate (HMFBA) and 5-(hydroxymethyl)-1,3-phenylene bis(2-methylacrylate) (HMFBM) monomers and its evaluation as Bis-GMA eluents in the formulation of composite resins for dental use. The experimental materials formulated with HMFBA and HMFBM monomers presented flexural strength values similar to those of the control group formulated with Bis-GMA/TEGDMA. Regarding volumetric contraction percentage, the values obtained of experimental materials with HMFBA was 1.88% and for HMFBM was 4.15%, both lower than control resin (4.68%). In the case of double bond conversion, the resin formulated with HMFBA monomer exhibited a greater degree of conversion (87%). Besides, the DMA analyses proved that the values for Tg guarantee a good mechanical performance at body temperature. The new resins formulated with HMFBA and HMFBM monomers exhibit a cellular viability close to 100%, which indicates the absence of cytotoxicity towards fibroblastic cells.
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Affiliation(s)
- Alma A Pérez-Mondragón
- Doctorado en Ciencias de los Materiales, Universidad Autónoma del Estado de Hidalgo, Carretera Pachuca-Tulancingo Km, 4.5 Colonia Carboneras, Mineral de la Reforma Hidalgo C.P. 42184, Mexico
| | - Carlos E Cuevas-Suárez
- Área Académica de Odontología, Instituto de Ciencias de la Salud, Universidad Autónoma del Estado de Hidalgo, Circuito ex-Hacienda la Concepción Km, 1.5 San Agustín Tlaxiaca, Hidalgo C.P. 42160, Mexico
| | - Oscar R Suárez Castillo
- Área Académica de Química, Instituto de Ciencias Básicas e Ingeniería, Universidad Autónoma del Estado de Hidalgo, Carretera Pachuca-Tulancingo Km, 4.5 Colonia Carboneras, Mineral de la Reforma Hidalgo C.P. 42184, Mexico
| | - J Abraham González-López
- Doctorado en Ciencias de los Materiales, Universidad Autónoma del Estado de Hidalgo, Carretera Pachuca-Tulancingo Km, 4.5 Colonia Carboneras, Mineral de la Reforma Hidalgo C.P. 42184, Mexico
| | - Ana M Herrera-González
- Laboratorio de Polímeros, Instituto de Ciencias Básicas e Ingeniería, Universidad Autónoma del Estado de Hidalgo, Carretera Pachuca-Tulancingo Km, 4.5 Colonia Carboneras, Mineral de la Reforma Hidalgo C.P. 42184, Mexico.
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Kamoun EA, El-Betany A, Menzel H, Chen X. Influence of photoinitiator concentration and irradiation time on the crosslinking performance of visible-light activated pullulan-HEMA hydrogels. Int J Biol Macromol 2018; 120:1884-1892. [DOI: 10.1016/j.ijbiomac.2018.10.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Revised: 09/10/2018] [Accepted: 10/01/2018] [Indexed: 10/28/2022]
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Kamoun EA, Abu-Saied M, Doma A, Menzel H, Chen X. Influence of degree of substitution and folic acid coinitiator on pullulan-HEMA hydrogel properties crosslinked under visible-light initiating system. Int J Biol Macromol 2018; 116:1175-1185. [DOI: 10.1016/j.ijbiomac.2018.05.100] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 05/03/2018] [Accepted: 05/15/2018] [Indexed: 10/16/2022]
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Feng Y, Wu Q, Hu J, Xu Z, Peng C. Study on affecting factors of curing rate in ultraviolet curing adhesives containing modified acrylic ester prepolymers. JOURNAL OF MACROMOLECULAR SCIENCE PART A-PURE AND APPLIED CHEMISTRY 2018. [DOI: 10.1080/10601325.2018.1482471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Yefeng Feng
- School of Mechanical and Electrical Engineering, Yangtze Normal University, Chongqing, P. R. China
| | - Qin Wu
- Department of Fashion Communication and Media, Jiangxi Institute of Fashion Technology, Nanchang, P. R. China
| | - Jianbing Hu
- School of Mechanical and Electrical Engineering, Yangtze Normal University, Chongqing, P. R. China
| | - Zhichao Xu
- Ministry of Education’s Key Laboratory of Poyang Lake Wetland and Watershed Research, Jiangxi Normal University, Nanchang, P. R. China
| | - Cheng Peng
- School of Mechanical and Electrical Engineering, Yangtze Normal University, Chongqing, P. R. China
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Effect of Camphorquinone Concentration in Physical-Mechanical Properties of Experimental Flowable Resin Composites. BIOMED RESEARCH INTERNATIONAL 2018; 2018:7921247. [PMID: 29951545 PMCID: PMC5987321 DOI: 10.1155/2018/7921247] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 04/03/2018] [Accepted: 04/11/2018] [Indexed: 12/15/2022]
Abstract
The aim of this study was to evaluate the effect of camphorquinone concentration in physical-mechanical properties of experimental flowable composites in order to find the concentration that results in maximum conversion, balanced mechanical strength, and minimum shrinkage stress. Model composites based on BISGMA/TEGDMA with 70% wt filler loading were prepared containing different concentrations of camphorquinone (CQ) on resin matrix (0.25%, 0.50%, 1%, 1.50%, and 2% by weight). Degree of conversion was determined by FTIR. Surface hardness was assessed before and after 24 h ethanol storage and softening rate was determined. Depth of cure was determined by Knoop hardness evaluation at different depths. Color was assessed by reflectance spectrophotometer, employing the CIE-Lab system. Flexural strength and elastic modulus were determined by a three-point bending test. Shrinkage stress was determined in a Universal Testing Machine in a high compliance system. Data were submitted to ANOVA and Tukey's test (α = 0.05). The increase in CQ concentration caused a significant increase on flexural strength and luminosity of composites. Surface hardness was not affected by the concentration of CQ. Composite containing 0.25% wt CQ showed lower elastic modulus and shrinkage stress when compared to others. Depth of cure was 3 mm for composite containing 1% CQ and 2 mm for the other tested composites. Degree of conversion was inversely correlated with softening rate and directly correlated with elastic modulus and shrinkage stress. In conclusion, CQ concentration affects polymerization characteristics and mechanical strength of composites. The concentration of CQ in flowable composite for optimized polymerization and properties was 1% wt of the resin matrix, which allows adequate balance among degree of conversion, depth of cure, mechanical properties, and color characteristics of these materials.
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Wang J, Yu Q, Yang Z. Effect of hydrophobic surface treated fumed silica fillers on a one-bottle etch and rinse model dental adhesive. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2017; 29:10. [PMID: 29275438 DOI: 10.1007/s10856-017-6015-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 12/05/2017] [Indexed: 06/07/2023]
Abstract
The objective of this study was to investigate the effect of hydrophobic surface treatment to fumed silica fillers on the bonding performance of a one-bottle etch and rinse model dental adhesive. In this study, 0.5-5 wt.% of Filler 1 and Filler 2 were loaded into BisGMA/HEMA model dental adhesive. Filler 1 was not treated, while Filler 2 was surface treated with a dimethyl silicone fluid making the silica extremely hydrophobic. The prepared adhesives were characterized through measurements of viscosity, degree of conversion, and water contact angle. SEM was utilized to observe the microstructures at the bonding interface. Micro-tensile bond strength (µTBS) test coupled with fracture surface analysis was carried out to study the mechanical properties. From the experiment, the loadings of Filler 2 is favorable to the improvement of µTBS. The µTBS of experimental adhesive with 1 wt.% Filler 2 increased 42% compared to the model adhesive without filler, and 24% compared to the experimental adhesive with 1 wt.% Filler 1. The effectively penetration of the hydrophobic compositions of the adhesive is considered as the main reason that leads to the increased bond strength, which was proved by the contact angle measurement and SEM observations.
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Affiliation(s)
- Jing Wang
- Department of Mechanical and Aerospace Engineering, University of Missouri, Columbia, MO, USA.
| | - Qingsong Yu
- Department of Mechanical and Aerospace Engineering, University of Missouri, Columbia, MO, USA
| | - Zhiyuan Yang
- Department of Chemical Engineering, University of Missouri, Columbia, MO, USA
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Grohmann CVS, Soares EF, Souza-Junior EJC, Brandt WC, Puppin-Rontani RM, Geraldeli S, Sinhoreti MAC. Influence of Different Concentration and Ratio of a Photoinitiator System on the Properties of Experimental Resin Composites. Braz Dent J 2017; 28:726-730. [DOI: 10.1590/0103-6440201701372] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 09/11/2017] [Indexed: 11/21/2022] Open
Abstract
Abstract The aim in this study was to evaluate the influence of different ratio of camphorquinone/tertiary amine concentration on the flexural strength (FS), elastic modulus (EM), degree of conversion (DC), yellowing (YL), water sorption (WS) and water solubility (WSL) of experimental composites. Thus, acrylate blends were prepared with different camphorquinone (CQ) and amine (DABE) concentrations and ratios by weight: (CQ/DABE%): 0.4/0.4% (C1), 0.4/0.8% (C2), 0.6/0.6% (C3), 0.6/1.2% (C4), 0.8/0.8% (C5), 0.8/1.6% (C6), 1.0/1.0% (C7), 1.0/2.0% (C8), 1.5/1.5% (C9), 1.5/3.0% (C10). For the FS and EM, rectangular specimens (7x2x1 mm, n=10) were photo-activated by single-peak LED for 20 s and tested at Instron (0.5 mm/min). Then, the same specimens were evaluated by FTIR for DC measurement. For YL, disks (5x2 mm, n=10) were prepared, light-cured for 20 s and evaluated in spectrophotometer using the b aspect of the CIEL*a*b* system. For WS and WSL, the volume of the samples was calculated (mm³). For WS and WSL, composites disks (5x0.5 mm, n=5) were prepared. After desiccation, the specimens were stored in distilled water for 7 days and again desiccated, in order to measure the WS and WSL. Data were submitted to one-way ANOVA and Tukey’s test (5%). The groups C8, C9 and C10 showed higher DC, EM and YL means, compared to other composites. Therefore, the FS and WS values were similar among all groups. Also, C1, C2 and C3 presented higher WSL in 7 days, compared to other composites. In general, higher concentrations of camphorquinone promoted higher physical-mechanical properties; however, inducing higher yellowing effect for the experimental composites
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Kamoun EA, Winkel A, Eisenburger M, Menzel H. Carboxylated camphorquinone as visible-light photoinitiator for biomedical application: Synthesis, characterization, and application. ARAB J CHEM 2016. [DOI: 10.1016/j.arabjc.2014.03.008] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Meereis CT, Leal FB, Ogliari FA. Stability of initiation systems in acidic photopolymerizable dental material. Dent Mater 2016; 32:889-98. [DOI: 10.1016/j.dental.2016.03.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 06/19/2015] [Accepted: 03/22/2016] [Indexed: 11/30/2022]
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Comparison of the Physical and Mechanical Properties of Resin Matrix with Two Photoinitiator Systems in Dental Adhesives. Polymers (Basel) 2016; 8:polym8070250. [PMID: 30974526 PMCID: PMC6432356 DOI: 10.3390/polym8070250] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 06/13/2016] [Accepted: 06/27/2016] [Indexed: 11/27/2022] Open
Abstract
This study evaluated the physical and mechanical properties of resin matrices in dental adhesives with two photoinitiator systems. Resin matrix specimens were made with five different kinds of photoinitiators. Neat resin consisted of 60% 2,2-bis[4-2(2-hydroxy-3-methacryloxypropoxy)phenyl]propane (Bis-GMA) and 40% hydroxyethyl methacrylate (HEMA) by weight, along with camphorquinone (CQ, 1 mol %) and additional components (1 mol % each) as follows: Group 1, 2-(dimethylamino)ethyl methacrylate (DMAEMA); Group 2, ethyl-4-(dimethylamino) benzoate (EDMAB); Group 3, diphenyliodonium hexafluorphosphate (DPIHFP); Group 4, DMAEMA+DPIHFP; Group 5, EDMAB+DPIHFP. The degree of conversion (DC), flexural strength, flexural modulus, microhardness, and ultimate tensile strength were tested. The contribution of each photoinitiator to the DC in a selected group was analyzed with contour plots. One-way ANOVA and Tukey tests (p < 0.05) were used for statistical analyses. The DC of Groups 2, 4, and 5 was similar. The flexural strength was similar in all groups, but flexural modulus was significantly different. Group 3 had the lowest values for all physical and mechanical properties. Among all methods, the microhardness test revealed the greatest degree of difference among the five specimens. CQ, EDMAB, and DPIHFP were the most effective photoinitiators and CQ was the most influential factor for the DC rate.
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Effects of a low-shrinkage methacrylate monomer and monoacylphosphine oxide photoinitiator on curing efficiency and mechanical properties of experimental resin-based composites. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2016; 58:487-94. [DOI: 10.1016/j.msec.2015.08.054] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 07/20/2015] [Accepted: 08/25/2015] [Indexed: 11/21/2022]
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Lee DH, Mai HN, Yang JC, Kwon TY. The effect of 4,4'-bis(N,N-diethylamino) benzophenone on the degree of conversion in liquid photopolymer for dental 3D printing. J Adv Prosthodont 2015; 7:386-91. [PMID: 26576255 PMCID: PMC4644780 DOI: 10.4047/jap.2015.7.5.386] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 08/20/2015] [Accepted: 08/27/2015] [Indexed: 11/18/2022] Open
Abstract
PURPOSE The purpose of this preliminary study was to investigate the effects of adding 4,4'-bis(N,N-diethylamino) benzophenone (DEABP) as a co-initiator to a binary photoinitiating system (camphorquinone-amine) to analyze on the degree of conversion (DC) of a light-cured resin for dental 3D printing. MATERIALS AND METHODS Cylindrical specimens (N=60, n=30 per group, ø5 mm × 1 mm) were fabricated using bisphenol A glycerolate dimethacrylate (BisGMA) both with and without DEABP. The freshly mixed resins were exposed to light in a custom-made closed chamber with nine light-emitting diode lamps (wavelength: 405 nm; power: 840 mW/cm2) for polymerization at each incidence of light-irradiation at 10, 30, 60, 180, and 300 seconds, while five specimens at a time were evaluated at each given irradiation point. Fourier-transform infrared (FTIR) spectroscopy was used to measure the DC values of the resins. Two-way analysis of variance and the Duncan post hoc test were used to analyze statistically significant differences between the groups and given times (α=.05). RESULTS In the DEABP-containing resin, the DC values were significantly higher at all points in time (P<.001), and also the initial polymerization velocity was faster than in the DEABP-free resin. CONCLUSION The addition of DEABP significantly enhanced the DC values and, thus, could potentially become an efficient photoinitiator when combined with a camphorquinone-amine system and may be utilized as a more advanced photopolymerization system for dental 3D printing.
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Affiliation(s)
- Du-Hyeong Lee
- Department of Prosthodontics, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea
| | - Hang Nga Mai
- Department of Prosthodontics, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea
| | - Jin-Chul Yang
- Department of Polymer Science & Engineering, School of Applied Chemical Engineering, Kyungpook National University, Daegu, Republic of Korea
| | - Tae-Yub Kwon
- Department of Dental Biomaterials, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea
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Erfan M, Jafarzadeh-Kashi TS, Ghadiri M, Rakhshan V. The effects of dentin bonding agent formulas on their polymerization quality, and together with tooth tissues on their microleakage and shear bond strength: an explorative 3-step experiment. J Adv Prosthodont 2014; 6:333-45. [PMID: 25352955 PMCID: PMC4211049 DOI: 10.4047/jap.2014.6.5.333] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 04/23/2014] [Accepted: 04/29/2014] [Indexed: 12/02/2022] Open
Abstract
PURPOSE Bonding agents (BA) are the crucial weak link of composite restorations. Since the commercial materials' compositions are not disclosed, studies to formulize the optimum ratios of different components are of value. The aim of this study was to find a proper formula of BAs. MATERIALS AND METHODS This explorative experimental in vitro study was composed of 4 different sets of extensive experiments. A commercial BA and 7 experimental formulas were compared in terms of degree of conversion (5 experimental formulas), shear bond strength, mode of failure, and microleakage (3 experimental formulas). Statistical analyses were performed (α=.05). The DC of selected formula was tested one year later. RESULTS The two-way ANOVA indicated a significant difference between the shear bond strength (SBS) of two tissues (dentin vs. enamel, P=.0001) in a way that dentinal bonds were weaker. However, there was no difference between the four materials (P=.283). The adhesive mode of failure was predominant in all groups. No differences between the microleakage of the four materials at occlusal (P=.788) or gingival (P=.508) sites were detected (Kruskal-Wallis). The Mann-Whitney U test showed a significant difference between the microleakage of all materials (3 experimental formulas and a commercial material) together at the occlusal site versus the gingival site (P=.041). CONCLUSION A formula with 62% bisphenol A-glycidyl methacrylate (Bis-GMA), 37% hydroxy ethyl methacrylate (HEMA), 0.3% camphorquinone (CQ), and 0.7% dimethyl-para-toluidine (DMPT) seems a proper formula for mass production. The microleakage and SBS might be respectively higher and lower on dentin compared to enamel.
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Affiliation(s)
- Mohmmad Erfan
- Department of Pharmaceutics, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Tahereh Sadat Jafarzadeh-Kashi
- Iranian Tissue Bank and Research Center, Department of Dental Materials, Faculty of Dentistry, Research Center for Sciences and Technology in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Vahid Rakhshan
- Iranian Tissue Bank and Research Center, Tehran University of Medical Sciences, Tehran, Iran. ; Department of Dental Anatomy and Morphology, Dental Branch, Islamic Azad University, Tehran, Iran
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Santini A, McGuinness N, Nor NAM. Degree of conversion of resin-based orthodontic bonding materials cured with single-wave or dual-wave LED light-curing units. J Orthod 2014; 41:292-8. [PMID: 25074905 DOI: 10.1179/1465313314y.0000000101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
AIM To evaluate the degree of conversion (DC) of orthodontic adhesives (RBOAs) cured with dual peak or single peak light-emitting diode (LED) light-curing units (LCUs). MATERIALS AND METHODS Standardized samples of RBOAs, APCPlus, Opal® Bond® and LightBond(TM) were prepared (n = 3) and cured with one of two dual peak LCUs (bluephase® G2-Ivoclar-Vivadent or Valo-Ultradent) or a single peak control (bluephase® Ivoclar-Vivadent). The DC was determined using micro-Raman spectroscopy. The presence or absence of initiators other than camphorquinone was confirmed by high-performance liquid chromatography and nuclear magnetic resonance spectroscopy. Data were analysed using general linear model in Minitab 15 (Minitab Inc., State College, PA, USA). RESULTS There was no significant difference in DC between APCPlus, and Opal® Bond (confidence interval: -3.89- to 2.48); significant difference between APCPlus and LightBond(TM) (-18.55 to -12.18) and Opal® Bond and Lightbond(TM) (-17.85 to -11.48); no significant difference between bluephase (single peak) and dual peak LCUs, bluephase G2 (-4.896 to 1.476) and Valo (-3.935 to 2.437) and between bluephase G2 and Valo (-2.225 to 4.147). APCPlus and Opal® Bond showed higher DC values than LightBond(TM) (P<0.05). Lucirin® TPO was found only in Vit-l-escence. CONCLUSION Lucirin® TPO was not identified in the three orthodontic adhesives. All three LCUs performed similarly with the orthodontic adhesives: orthodontic adhesive make had a greater effect on DC than the LCUs. It is strongly suggested that manufacturers of resin-based orthodontic materials test report whether or not dual peak LCUs should be used with their materials. Dual peak LED LCUs, though suitable in the majority of cases, may not be recommended for certain non Lucirin® TPO-containing materials.
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Affiliation(s)
- Ario Santini
- Director Biomaterial Research, Edinburgh Dental Institute, Lauriston Buildings, Lauriston Place, Edinburgh EH3 9HA
| | - Niall McGuinness
- Orthodontic Consultant , Edinburgh Dental Institute, Lauriston Buildings, Lauriston Place, Edinburgh EH3 9HA
| | - Noor Azreen Md Nor
- Postgraduate Student, Department of Orthodontics, Edinburgh Dental Institute, Lauriston Buildings, Lauriston Place, Edinburgh EH3 9HA
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Pongprueksa P, Miletic V, Janssens H, Van Landuyt KL, De Munck J, Godderis L, Van Meerbeek B. Degree of conversion and monomer elution of CQ/amine and TPO adhesives. Dent Mater 2014; 30:695-701. [DOI: 10.1016/j.dental.2014.03.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 11/21/2013] [Accepted: 03/19/2014] [Indexed: 11/30/2022]
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Randolph LD, Palin WM, Bebelman S, Devaux J, Gallez B, Leloup G, Leprince JG. Ultra-fast light-curing resin composite with increased conversion and reduced monomer elution. Dent Mater 2014; 30:594-604. [PMID: 24679406 DOI: 10.1016/j.dental.2014.02.023] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2013] [Revised: 02/13/2014] [Accepted: 02/25/2014] [Indexed: 12/20/2022]
Abstract
OBJECTIVES To test the null hypotheses that photoactive resin composites containing a Type I photoinitiator would exhibit reduced DC or increased monomer elution at substantially short curing times compared with materials based on a Type 2 ketone/amine system. METHODS Two experimental resin composites were prepared, using either Lucirin-TPO or camphorquinone/DMAEMA. Specimens were light-cured using appropriate spectral emission that coincided with the absorption properties of each initiator using different irradiation protocols (0.5, 1, 3, 9s at 500, 1000 and 2000mW/cm(2) for Lucirin-TPO based composites and 20 or 40s at 1000mW/cm(2) for Lucirin-TPO and camphorquinone-based composites). Degree of conversion (DC) was measured by Raman spectroscopy, propagating radical concentrations were collected by means of electron paramagnetic resonance (EPR) and monomer leaching was characterized using high-performance liquid chromatography (HPLC). RESULTS The null hypotheses were rejected, except for a single irradiation protocol (0.5s @ 500mW/cm(2)). Lucirin-TPO-based composites could cure 20 times faster and release at least 4 times less monomers in comparison to camphorquinone-based composites. At 1000mW/cm(2), and 1s irradiation time for curing times of 1s, Lucirin-TPO based composites displayed 10% higher DC. The difference in polymerization efficiency of Lucirin-TPO compared with camphorquinone-based resin composites were explained using EPR; the former showing a significantly greater yield of radicals which varied logarithmically with radiant exposure. SIGNIFICANCE Lucirin-TPO is substantially more efficient at absorbing and converting photon energy when using a curing-light with an appropriate spectral emission and otherwise a limitation noted in several previous publications. At concentrations of 0.0134mol/L, Lucirin-TPO-based composites require a minimum light intensity of 1000mW/cm(2) and an exposure time of 1s to provide significantly improved DC and minimal elution compared with a conventional photoinitiator system. The use of a wide range of curing protocols in the current experiment has realized the significant potential of Lucirin-TPO and its impact for clinical applications, in replacement to materials using camphorquinone.
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Affiliation(s)
- Luc D Randolph
- Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium; Institute of Condensed Matter and Nanosciences, Bio- and Soft- Matter, Université catholique de Louvain, Louvain-la-Neuve, Belgium; CRIBIO (Center for Research and Engineering on Biomaterials), Brussels, Belgium.
| | - William M Palin
- Biomaterials Unit, University of Birmingham, College of Medical and Dental Sciences, School of Dentistry, St Chad's Queensway, Birmingham B4 6NN, UK
| | - Sabine Bebelman
- Institute of Condensed Matter and Nanosciences, Bio- and Soft- Matter, Université catholique de Louvain, Louvain-la-Neuve, Belgium; CRIBIO (Center for Research and Engineering on Biomaterials), Brussels, Belgium
| | - Jacques Devaux
- Institute of Condensed Matter and Nanosciences, Bio- and Soft- Matter, Université catholique de Louvain, Louvain-la-Neuve, Belgium; CRIBIO (Center for Research and Engineering on Biomaterials), Brussels, Belgium
| | - Bernard Gallez
- Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium; CRIBIO (Center for Research and Engineering on Biomaterials), Brussels, Belgium
| | - Gaetane Leloup
- Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium; Institute of Condensed Matter and Nanosciences, Bio- and Soft- Matter, Université catholique de Louvain, Louvain-la-Neuve, Belgium; CRIBIO (Center for Research and Engineering on Biomaterials), Brussels, Belgium; School of Dentistry and Stomatology, Université catholique de Louvain, Brussels, Belgium
| | - Julian G Leprince
- Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium; Institute of Condensed Matter and Nanosciences, Bio- and Soft- Matter, Université catholique de Louvain, Louvain-la-Neuve, Belgium; CRIBIO (Center for Research and Engineering on Biomaterials), Brussels, Belgium; School of Dentistry and Stomatology, Université catholique de Louvain, Brussels, Belgium
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Karakis D, Yildirim-Bicer AZ, Erol O, Dogan A. Effects of different polymerization protocols on the degree of conversion of two dual-cured core buildup composites polymerized by light-emitting diode and halogen light-curing units. J Appl Polym Sci 2014. [DOI: 10.1002/app.40560] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Duygu Karakis
- Department of Prosthodontics; Faculty of Dentistry; University of Gazi; Ankara Turkey
| | | | - Ozlem Erol
- Department of Chemistry; Faculty of Science; University of Gazi; Ankara Turkey
| | - Arife Dogan
- Department of Prosthodontics; Faculty of Dentistry; University of Gazi; Ankara Turkey
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Zhang Y, Wang Y. Photopolymerization of phosphoric acid ester-based self-etch dental adhesives. Dent Mater J 2014; 32:10-8. [PMID: 23370865 DOI: 10.4012/dmj.2012-108] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The objective of the study was to gain more understanding on the photopolymerization mechanism and the role of individual monomers in the polymerization behavior of a PAE-based self-etch adhesive system with the presence of HAp and water. The photo-polymerization process of the model adhesive system (2MP/HEMA) was monitored by using real-time attenuated total reflectance Fourier transform infrared (ATR/FT-IR) technique. The effect of monomer ratio, HAp incorporation, and water content were investigated. The degree of conversion (DC) and the polymerization rate (PR) of the adhesives were determined to evaluate the polymerization efficacy. The results showed that the DC and PR increased consistently as the 2MP content increased from 30% to 70%, while they declined drastically as the 2MP content was further elevated to 100%. The incorporation of HAp considerably increased the DC and PR; however, the increase in water content was found to have negative influence on the photopolymerization.
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Affiliation(s)
- Ying Zhang
- Department of Oral Biology, University of Missouri-Kansas City School of Dentistry, Kansas City, MO 64108, USA
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Catelan A, Santo MRDE, Menegazzo LM, Moraes JCS, dos Santos PH. Effect of light curing modes on mechanical properties of direct and indirect composites. Acta Odontol Scand 2013; 71:697-702. [PMID: 22905998 DOI: 10.3109/00016357.2012.715193] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE To evaluate the degree of conversion (DC), flexural strength (FS) and Knoop microhardness (KHN) of direct and indirect composite resins polymerized with different curing systems. MATERIALS AND METHODS Specimens of direct (Z250, 3M/Espe) and indirect (Sinfony, 3M/Espe) restorative materials were made and polymerized using two light curing units: XL2500 (3M/Espe) and Visio system (3M/Espe). Absorption spectra of both composites were obtained on a FTIR spectrometer in order to calculate the DC. FS was evaluated in a universal testing machine and surface microhardness was performed in a microhardness tester (50gf/15s). DC, FS and KHN data were submitted to two-way ANOVA and Tukey's test (α = 0.05). RESULTS Z250 showed higher DC, FS and KHN compared with Sinfony when the polymerization was carried out with XL2500 (p < 0.05). However, there is no statistical difference in DC between the materials when Visio was used (p > 0.05). Visio showed higher DC and KHN for Z250 and Sinfony than the values obtained using XL2500 light curing (p < 0.05). For FS, no significant difference between curing units was found (p > 0.05). CONCLUSION Even though the Visio system could increase DC and KHN for some direct and indirect composites, compared with the conventional halogen curing unit, a high number of monomers did not undergo conversion during the polymerization.
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Affiliation(s)
- Anderson Catelan
- Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas, Piracicaba, São Paulo, Brazil.
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Hadis MA, Shortall AC, Palin WM. Competitive light absorbers in photoactive dental resin-based materials. Dent Mater 2012; 28:831-41. [PMID: 22578661 DOI: 10.1016/j.dental.2012.04.029] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 03/16/2012] [Accepted: 04/16/2012] [Indexed: 10/28/2022]
Abstract
OBJECTIVES The absorbance profile of photoinitiators prior to, during and following polymerization of light curable resin-based materials will have a significant effect on the cure and color properties of the final material. So-called "colorless" photoinitiators are used in some light-activated resin-based composite restorative materials to lessen the yellowing effect of camphoroquinone (CQ) in order to improve the esthetic quality of dental restorations. This work characterizes absorption properties of commonly used photoinitiators, an acylphosphine oxide (TPO) and CQ, and assesses their influence on material discoloration. METHODS Dimethacrylate resin formulations contained low (0.0134 mol/dm(3)), intermediate (0.0405 mol/dm(3)) or high (0.0678 mol/dm(3)) concentrations of the photoinitiators and the inhibitor, butylated hydroxytoluene (BHT) at 0, 0.1 or 0.2% by mass. Disc shaped specimens (n = 3) of each resin were polymerized for 60s using a halogen light curing unit. Dynamic measurements of photoinitiator absorption, polymer conversion and reaction temperature were performed. A spectrophotometer was used to measure the color change before and after cure. RESULTS GLM three-way analysis of variance revealed significant differences (p<0.001), where photoinitiator concentration (df = 2; F = 618.83)>photoinitiator type (df = 1; F = 176.12)>% BHT (df = 2, F = 13.17). BHT concentration affected the rate of polymerization and produced lower conversion in some of the CQ-based resins. Significant differences between photoinitiator type and concentrations were seen in color (where TPO resins became yellower and camphoroquinone resins became less yellow upon irradiation). Reaction temperature, kinetics and conversion also differed significantly for both initiators (p<0.001). Despite TPO-based resins producing a visually perceptible color change upon polymerization, the color change was significantly less than that produced with CQ-based resins. SIGNIFICANCE Although some photoinitiators such as TPO may be a more esthetic alternative to CQ, they may actually cause significant color contamination when used in high concentrations and therefore manufacturers should limit its concentration in order to improve its esthetic quality.
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Affiliation(s)
- Mohammed A Hadis
- Biomaterials Unit, University of Birmingham, School of Dentistry, College of Medical and Dental Sciences, St Chads Queensway, Birmingham B4 6NN, United Kingdom.
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Schneider LFJ, Cavalcante LM, Prahl SA, Pfeifer CS, Ferracane JL. Curing efficiency of dental resin composites formulated with camphorquinone or trimethylbenzoyl-diphenyl-phosphine oxide. Dent Mater 2012; 28:392-7. [DOI: 10.1016/j.dental.2011.11.014] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 11/01/2011] [Accepted: 11/10/2011] [Indexed: 11/16/2022]
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Kwon TY, Bagheri R, Kim YK, Kim KH, Burrow MF. Cure mechanisms in materials for use in esthetic dentistry. ACTA ACUST UNITED AC 2012; 3:3-16. [PMID: 22298515 DOI: 10.1111/j.2041-1626.2012.00114.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Affiliation(s)
- Tae-Yub Kwon
- Department of Dental Biomaterials, Kyungpook National University, Jung-gu, Daegu, Korea
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Network structures of Bis-GMA/TEGDMA resins differ in DC, shrinkage-strain, hardness and optical properties as a function of reducing agent. Dent Mater 2011; 27:497-506. [PMID: 21388670 DOI: 10.1016/j.dental.2011.02.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Accepted: 02/11/2011] [Indexed: 11/24/2022]
Abstract
OBJECTIVES To evaluate the influence of different tertiary amines on degree of conversion (DC), shrinkage-strain, shrinkage-strain rate, Knoop microhardness, and color and transmittance stabilities of experimental resins containing BisGMA/TEGDMA (3:1wt), 0.25wt% camphorquinone, 1wt% amine (DMAEMA, CEMA, DMPT, DEPT or DABE). Different light-curing protocols were also evaluated. METHODS DC was evaluated with FTIR-ATR and shrinkage-strain with the bonded-disk method. Shrinkage-strain-rate data were obtained from numerical differentiation of shrinkage-strain data with respect to time. Color stability and transmittance were evaluated after different periods of artificial aging, according to ISO 7491:2000. Results were evaluated with ANOVA, Tukey, and Dunnett's T3 tests (α=0.05). RESULTS Studied properties were influenced by amines. DC and shrinkage-strain were maximum at the sequence: CQ<DEPT<DMPT≤CEMA≈DABE<DMAEMA. Both DC and shrinkage were also influenced by the curing protocol, with positive correlations between DC and shrinkage-strain and DC and shrinkage-strain rate. Materials generally decreased in L* and increased in b*. The strong exception was the resin containing DMAEMA that did not show dark and yellow shifts. Color varied in the sequence: DMAEMA<DEPT<DMPT<CEMA<DABE. Transmittance varied in the sequence: DEPT≈DABE<DABE≈DMPT≈CEMA<DMPT≈CEMA≈DMAEMA, being more evident at the wavelength of 400nm. No correlations between DC and optical properties were observed. SIGNIFICANCE The resin containing DMAEMA showed higher DC, shrinkage-strain, shrinkage-strain rate, and microhardness, in addition to better optical properties.
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Brandt WC, Tomaselli LDO, Correr-Sobrinho L, Sinhoreti MAC. Can phenyl-propanedione influence Knoop hardness, rate of polymerization and bond strength of resin composite restorations? J Dent 2011; 39:438-47. [DOI: 10.1016/j.jdent.2011.03.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 03/29/2011] [Accepted: 03/31/2011] [Indexed: 10/18/2022] Open
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Photoinitiator type and applicability of exposure reciprocity law in filled and unfilled photoactive resins. Dent Mater 2011; 27:157-64. [DOI: 10.1016/j.dental.2010.09.011] [Citation(s) in RCA: 121] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 08/04/2010] [Accepted: 09/29/2010] [Indexed: 11/17/2022]
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Brandt WC, Schneider LFJ, Frollini E, Correr-Sobrinho L, Sinhoreti MAC. Effect of different photo-initiators and light curing units on degree of conversion of composites. Braz Oral Res 2010; 24:263-70. [DOI: 10.1590/s1806-83242010000300002] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Accepted: 05/17/2010] [Indexed: 11/22/2022] Open
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Musanje L, Ferracane JL, Sakaguchi RL. Determination of the optimal photoinitiator concentration in dental composites based on essential material properties. Dent Mater 2009; 25:994-1000. [PMID: 19328539 DOI: 10.1016/j.dental.2009.02.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2008] [Accepted: 02/23/2009] [Indexed: 10/21/2022]
Abstract
OBJECTIVES The aim of this study was to determine the concentrations of the photosensitizer (camphoroquinone, CQ) and coinitiator (ethyl-4-dimethylaminobenzoate, EDMAB) that resulted in maximum conversion but generated minimum contraction stress in experimental composites. METHODS Experimental composites were prepared with an identical resin formulation [TEGDMA:UDMA:bis-GMA of 30.25:33.65:33.65]. Five groups of resin were prepared at varied CQ concentrations (0.1, 0.2, 0.4, 0.8 and 1.6wt% of the resin). Five subgroups of resin were prepared at each level of CQ concentration, by adding EDMAB at 0.05, 0.1, 0.2, 0.4 and 0.8wt% of the resin, resulting in 25 experimental resins. Finally, strontium glass ( approximately 3microm) and silica (0.04microm) were added at 71.5 and 12.6wt% of the composite, respectively. Samples (n=3) were then evaluated for Knoop hardness (KHN), degree of conversion (DC), depth of cure (DoC) and contraction stress (CS). RESULTS There was an optimal CQ and EDMAB concentration that resulted in maximum DC and KHN, beyond which increased concentration resulted in a decline in those properties. KHN testing identified two regions of maxima with best overlaps occurring at CQ:EDMAB ratio of 1.44:0.42 and 1.05:1.65mol%. DC evaluation showed one region of maximum, the best overlap occurring at CQ:EDMAB ratio of 2.40:0.83mol%. DoC was 4mm. Overall, maximum CS was attained before the system reached the maximum possible conversion and hardness. SIGNIFICANCE (1) Selection of optimal photoinitiator/amine concentration is critical to materials' formulation, for excessive amounts can compromise materials' properties. (2) There was no sufficient evidence to suggest that contraction stress can be reduced by lowering CQ/EDMAB concentration without compromising DC and KHN.
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Affiliation(s)
- L Musanje
- Department of Cranial Facial Biology, School of Dentistry, University of Colorado, Mail Stop 8120, RC1-S, Rm P18 2103, 12801 E. 17th Ave., P.O. Box 6511, Aurora, CO 80045, USA.
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Schneider LFJ, Cavalcante LM, Consani S, Ferracane JL. Effect of co-initiator ratio on the polymer properties of experimental resin composites formulated with camphorquinone and phenyl-propanedione. Dent Mater 2008; 25:369-75. [PMID: 18848352 DOI: 10.1016/j.dental.2008.08.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 05/20/2008] [Accepted: 08/13/2008] [Indexed: 11/27/2022]
Abstract
OBJECTIVES To evaluate the effect of amine ratio (ethyl 4-dimethylaminobenzoate, EDMAB) on the maximum rate of polymerization (R(p)(max)), degree of conversion (DC), Knoop hardness (KH), water sorption (Wsp), water solubility (Wsl) and color changes (DeltaE) over time of resin composites formulated with the photoinitiators camphorquinone (CQ), phenylpropanedione (PPD) and CQ-PPD in combination. MATERIALS AND METHODS Experimental resin composites were made with photoinitiator:amine ratios of 2:1, 1:1, 1:1.5 and 1:2 by weight. R(p)(max) was evaluated with differential scanning calorimetry (DSC), DC with DSC and Fourier transformed infrared (FTIR) spectroscopy, KH with Knoop indentation, Wsp and Wsl adapted from ISO 4049; and color with a chromameter. The results were analyzed with two-way ANOVA/Tukey's multiple comparison test (p<0.05). RESULTS The higher the amine ratio in the composite, the higher was DC, R(p)(max), and KH, and the lower was Wsl, regardless of the photoinitiator type. The use of PPD alone resulted in poorer properties than CQ and CQ-PPD. Many factors seem to affect the color changes and the b-axis data revealed that the higher the amine ratio, the higher was the +b value (yellowing) for CQ and CQ-PPD formulations. CONCLUSIONS Higher amine ratios led to improved polymer properties, but also produced more yellowing in resin composites with CQ and CQ-PPD. The use of PPD alone was not advantageous for producing good final properties when compared to CQ and CQ-PPD.
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Kanayama H, Kanie T, Inoue K. Dynamic viscoelastic properties of photo-activated composite resins containing short glass fibres. J Oral Rehabil 2008. [DOI: 10.1111/j.1365-2842.2000.00613.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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David JR, Gomes OM, Gomes JC, Loguercio AD, Reis A. Effect of exposure time on curing efficiency of polymerizing units equipped with light-emitting diodes. J Oral Sci 2008; 49:19-24. [PMID: 17429178 DOI: 10.2334/josnusd.49.19] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
A study was conducted to evaluate the top and bottom hardness of two composites cured using polymerizing units equipped with light-emitting diodes [LED] (LEDemetron; Elipar FreeLight, Coltolux LED) and one quartz-tungsten halogen device [QTH] (Optilux 501) under different exposure times (20, 40 and 60 sec). A matrix mold 5 mm in diameter and 2 mm in depth was made to obtain five disc-shaped specimens for each experimental group. The specimens were cured by one of the light-curing units (LCUs) for 20, 40 or 60 sec, and the hardness was measured with a Vickers hardness-measuring instrument (50 g/30 sec). Data were subjected to three-way ANOVA and Tukey's test (alpha = 0.05). LED LCUs were as effective as the QTH device for curing both composites. A significant increase in the microhardness values were observed for all light LCUs when the exposure time was changed from 20 sec to 40 sec. The Z250 composite showed hardness values that were usually higher than those of the Charisma composite under similar experimental conditions. LED LCUs are as efficient for curing composites as the QTH device as long as an exposure time of 40 sec or higher is employed. An exposure time of 40 sec is required to provide composites with a uniform and high Knoop hardness when LED light-curing units are employed.
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Affiliation(s)
- José R David
- Department of Dentistry, School of Dentistry, University of Ponta Grossa, Campus Uvaranas, Brazil
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Influence of photoinitiator type on the rate of polymerization, degree of conversion, hardness and yellowing of dental resin composites. Dent Mater 2008; 24:1169-77. [PMID: 18325583 DOI: 10.1016/j.dental.2008.01.007] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2007] [Revised: 01/06/2008] [Accepted: 01/07/2008] [Indexed: 11/22/2022]
Abstract
OBJECTIVES To evaluate the degree of conversion (DC), maximum rate of polymerization (Rpmax), Knoop hardness (KHN) and yellowing (b-value) of resin composites formulated with phenylpropanedione (PPD), camphorquinone (CQ), or CQ/PPD at different concentrations. The hypotheses tested were (i) PPD or CQ/PPD would produce less Rpmax and yellowing than CQ alone without affecting DC and KHN, and (ii) Rpmax, DC, and KHN would be directly related to the absorbed power density (PDabs). METHODS CQ/amine, PPD/amine and CQ/PPD/amine were used at low, intermediate and high concentrations in experimental composites. Photoinitiator absorption and halogen-light emission were measured using a spectrophotometer, Rp with differential scanning calorimetry (DSC), DC with DSC and FTIR, KHN with Knoop indentation; and color with a chromameter. The results were analyzed with two-way analysis of variance (ANOVA)/Student-Newman-Keul's test (p<0.05). Correlation tests were carried out between PDabs and each of DC, Rpmax and KHN. RESULTS The PDabs increased with photoinitiator concentration and PPD samples had the lowest values. In general, maximum DC was comparable at intermediate concentration, while Rpmax and KHN required higher concentrations. DC was similar for all photoinitiators, but Rpmax was lower with PPD and CQ/PPD. PPD produced the lowest KHN. Yellowing increased with photoinitiator concentration. PPD did not reduce yellowing at intermediate and/or high concentrations, compared to CQ-formulations. PDabs showed significant correlations with DC, Rpmax and KHN. CONCLUSION PPD or CQ/PPD reduced Rpmax in experimental composites without affecting the DC. The use of PPD did not reduce yellowing, but reduced KHN. DC, Rpmax and KHN were dependent on PDabs.
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Namen FM, Galan J, De Deus G, Cabreira RD, Filho FCS. Effect of pH on the Wettability and Fluoride Release of an Ion-releasing Resin Composite. Oper Dent 2008; 33:571-8. [DOI: 10.2341/07-147] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Clinical Relevance
The effect of pH on the wettability and fluoride release of Ariston pHc was examined. It was determined that this material might interfere with plaque adhesion in the oral environment.
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Ogunyinka A, Palin WM, Shortall AC, Marquis PM. Photoinitiation chemistry affects light transmission and degree of conversion of curing experimental dental resin composites. Dent Mater 2007; 23:807-13. [PMID: 16914191 DOI: 10.1016/j.dental.2006.06.016] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2005] [Revised: 03/27/2006] [Accepted: 06/22/2006] [Indexed: 11/19/2022]
Abstract
INTRODUCTION The effect of photoinitiator and co-initiator chemistry on the setting reaction and degree of conversion of dental resin-based composites (RBCs) has rarely been determined explicitly. This work examines the effect of type and concentration of photoinitiator and co-initiator on the rate of change of light transmission throughout polymerisation and degree of conversion of model RBC formulations. METHODS Bisphenol-A diglycidyl ether dimethacrylate (bis-GMA) and triethylene glycol dimethacrylate (TEGDMA) (6:4 molar ratio) resins filled with silanized glass filler (74wt.%) and containing various photoinitiators (camphorquinone; CQ, 1-phenyl-1,2-propanedione; PPD, benzil; BZ), co-initiator types (N,N-dimethyl-p-amino benzoic acid ethyl ester; DABE, N,N-cyanoethyl methylaniline; CEMA, N,N-diethanol-p-toluidine; DEPT) and concentration (0.0-0.3% DABE) were polymerised using a halogen or LED light curing-unit (LCU) for 10, 20 and 40s. The setting reaction was monitored in real-time by measuring the light transmittance through the curing specimen and bulk degree of conversion (DC) evaluated using Fourier transform infra-red spectroscopy. RESULTS Specimens containing CQ and PPD cured with the halogen LCU did not have a significant effect on DC or changes in light transmission, although a significant increase in DC was observed for CQ compared with PPD specimens cured with the LED LCU. DABE and CEMA were more effective co-initiators than DEPT. Although DC was not limited by co-initiator concentration, the absence of a co-initiator resulted in marked differences in light transmission and decreased DC throughout 40s irradiation with each LCU type. CONCLUSIONS The spectral range emitted from different types of LCU and absorption characteristics of the photoinitiator chemistry of light-activated resin-based composites play a critical role in the efficiency of polymerisation.
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Affiliation(s)
- A Ogunyinka
- 8th Floor, Biomaterials Unit, School of Dentistry, University of Birmingham, St Chad's Queensway, Birmingham B4 6NN, UK
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Van Landuyt KL, Snauwaert J, De Munck J, Peumans M, Yoshida Y, Poitevin A, Coutinho E, Suzuki K, Lambrechts P, Van Meerbeek B. Systematic review of the chemical composition of contemporary dental adhesives. Biomaterials 2007; 28:3757-85. [PMID: 17543382 DOI: 10.1016/j.biomaterials.2007.04.044] [Citation(s) in RCA: 729] [Impact Index Per Article: 42.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2007] [Accepted: 04/26/2007] [Indexed: 11/22/2022]
Abstract
Dental adhesives are designed to bond composite resins to enamel and dentin. Their chemical formulation determines to a large extent their adhesive performance in clinic. Irrespective of the number of bottles, an adhesive system typically contains resin monomers, curing initiators, inhibitors or stabilizers, solvents and sometimes inorganic filler. Each one of these components has a specific function. The aim of this article is to systematically review the ingredients commonly used in current dental adhesives as well as the properties of these ingredients. This paper includes an extensive table with the chemical formulation of contemporary dental adhesives.
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Affiliation(s)
- Kirsten 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
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Schroeder W, Arenas G, Vallo C. Monomer conversion in a light-cured dental resin containing 1-phenyl-1,2- propanedione photosensitizer. POLYM INT 2007. [DOI: 10.1002/pi.2239] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Yoshida T, Yamaguchi K, Tsubota K, Takamizawa T, Kurokawa H, Rikuta A, Ando S, Miyazaki M. Effect of metal conditioners on polymerization behavior of bonding agents. J Oral Sci 2005; 47:171-5. [PMID: 16415560 DOI: 10.2334/josnusd.47.171] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
This study aimed to determine the influence of metal conditioners on the polymerization behavior of bonding agents. Bonding agents of two-step self-etching primer systems and metal conditioners for adhesion of dental metal alloys were used. Double bond conversion was determined by Fourier transform-ation infrared spectroscopy. The percentage of residual double bonds, including pendant and monomeric double bonds, was calculated by comparing the obtained ratio with that of the uncured bonding agent. The degree of conversion of the bonding agents was obtained by subtracting the remaining double bonds from 100%. ANOVA followed by a Tukey HDS test was performed. Degree of conversion of the bonding agents ranged from 86.0 to 87.8%. When the bonding agents were mixed with metal conditioners or solvents of the metal conditioners, double bond conversion of the bonding agents tended to decrease. Within the limitations of this study, which was far removed from clinical situations, the presence of metal conditioners and remaining solvents had adverse effects on the polymerization reaction of bonding agents. Clinicians should be cognizant of the various factors that can influence bond strength of restorative resins to dentin.
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Viljanen EK, Lassila LVJ, Skrifvars M, Vallittu PK. Degree of conversion and flexural properties of a dendrimer/methyl methacrylate copolymer: design of experiments and statistical screening. Dent Mater 2005; 21:172-7. [PMID: 15681016 DOI: 10.1016/j.dental.2003.12.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2003] [Revised: 11/03/2003] [Accepted: 12/23/2003] [Indexed: 11/29/2022]
Abstract
OBJECTIVES The aim of this study was to investigate the effect of photosensitive initiator and activator concentrations on the degree of conversion and flexural properties of an experimental photopolymerized dental copolymer containing dendrimer. METHODS The experimental resin system consisted of a dendrimer with 12 methacrylate groups and methyl methacrylate in a mass ratio of 80:20. The initiator and activator used were camphorquinone and 2-(N,N-dimethylamino)ethyl methacrylate, whose concentrations varied individually from 1 to 4 wt%. The degree of conversion was determined with FTIR spectroscopy, and flexural strength and flexural modulus with the three-point bending test. The experiments were designed and analyzed, and the results plotted with Modde 5.0 software. RESULTS The highest degree of conversion was obtained with 2.5 wt% initiator and activator concentrations, the highest flexural strength with 2.5 wt% initiator and 1.0 wt% activator concentration, and the highest flexural modulus with 1.0 wt% initiator and activator concentrations. SIGNIFICANCE The results indicated that the degree of conversion increased, and flexural strength and flexural modulus decreased, with increasing initiator and activator concentrations. The high concentrations of initiator probably inhibited the transmittance of the active wavelengths to the depths of the samples (the inner filter effect), resulting in inhomogeneous conversion and thus decreased mechanical properties.
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Affiliation(s)
- Eeva K Viljanen
- Department of Prosthetic Dentistry and Biomaterials Research, Institute of Dentistry, University of Turku, Lemminkäisenkatu 2, FIN-20520 Turku, Finland.
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Davidenko N, García O, Sastre R. Photopolymerization kinetics of dimethacrylate-based light-cured dental resins. J Appl Polym Sci 2005. [DOI: 10.1002/app.21828] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Satsangi N, Rawls HR, Norling BK. Synthesis of low-shrinkage polymerizable methacrylate liquid-crystal monomers. J Biomed Mater Res B Appl Biomater 2005; 74:706-11. [PMID: 15991230 DOI: 10.1002/jbm.b.30297] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
As a part of the continuous pursuit to develop an ideal resinous dental restorative material for use in large posterior cavity restorations, this article reports the easy, high-yield synthesis and the incredibly low polymerization shrinkage property of a new bifunctional liquid crystal (LC) monomer. This new polymerizable nematic liquid crystal is the next higher homolog of the acrylate monomer reported in a previous work.1 It remains liquid crystalline between room and mouth temperatures and can be polymerized to isotropic polymer with the use of the same visible light inhibitor system as used with conventional monomers. The structure of this new monomer has been confirmed to be 2-(t-butyl), 1,4-bis-[4-(6-methacryloxy-hexan-1-oxy)-benzoyloxy]-benzene. Unlike the synthesis of its acrylate homolog, when the same procedure is adopted for the synthesis of this compound, the recovery of the product is not split by a sizable amount of the by-product. Therefore, the reaction is cleaner, with high yield and a less labor-intensive purification procedure. Thus, the synthetic methodology has the potential for easy commercial scale-up. The monomer (V) polymerizes at room temperature with a shrinkage of about 2 vol %, as compared to > 8 vol % for conventional control (GTE), at similar degrees of conversion.
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Affiliation(s)
- Neera Satsangi
- Division of Biomaterials, Department of Restorative Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229, USA.
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