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Wang C, Xiao H, Lu Y, Lv J, Yuan Z, Cheng J. Regulation of Polymerization Kinetics to Improve Crystallinity of Carbon Nitride for Photocatalytic Reactions. ChemSusChem 2023; 16:e202300361. [PMID: 37139577 DOI: 10.1002/cssc.202300361] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 05/02/2023] [Accepted: 05/03/2023] [Indexed: 05/05/2023]
Abstract
Carbon nitride (CN) polymers exhibit tunable and fascinating physicochemical properties and are thus an essential class of photocatalytic materials with potential applications. Although significant progress has been made in the fabrication of CN, the preparation of metal-free crystalline CN via a straightforward method remains a considerable challenge. Herein, we describe a new attempt to synthesize crystalline carbon nitride (CCN) with a well-developed structure through regulation of the polymerization kinetics. The synthetic process involves the pre-polymerization of melamine to remove most of the ammonia and further calcination of the pre-heated melamine in the presence of copper oxide as an ammonia absorbent. Copper oxide can decompose the ammonia produced by the polymerization process, thereby promoting the reaction. These conditions facilitate the polycondensation process while avoiding carbonization of the polymeric backbone at high temperatures. Owing to the high crystallinity, nanosheet structure, and efficient charge-carrier transmission capacity, the as-prepared CCN catalyst shows much higher photocatalytic activity than its counterparts. Our study provides a novel strategy for the rational design and synthesis of high-performance carbon nitride photocatalysts by simultaneously optimizing polymerization kinetics and crystallographic structures.
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Affiliation(s)
- Chong Wang
- State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
- College of Materials Engineering, Fujian Agriculture and Forestry University, Fuzhou, 35002, P. R. China
| | - Hongxiang Xiao
- State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
| | - Yichun Lu
- School of Energy and Environment, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, P. R. China
| | - Jinliang Lv
- State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
| | - Zhanhui Yuan
- College of Materials Engineering, Fujian Agriculture and Forestry University, Fuzhou, 35002, P. R. China
| | - Jiajia Cheng
- State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
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Tosaka M, Takeuchi H, Kibune M, Tong T, Zhu N, Yamago S. Stochastic Simulation of Controlled Radical Polymerization Forming Dendritic Hyperbranched Polymers. Angew Chem Int Ed Engl 2023:e202305127. [PMID: 37194984 DOI: 10.1002/anie.202305127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 05/16/2023] [Accepted: 05/17/2023] [Indexed: 05/18/2023]
Abstract
Stochastic simulation of the formation process of hyperbranched polymers (HBPs) based on the reversible deactivation radical polymerization (RDRP) using a branch-inducing monomer, evolmer, has been carried out. The simulation program successfully reproduced the change of dispersities (Đs) during the polymerization process. Furthermore, the simulation suggested that the observed Đs (= 1.5~2) are due to the distribution of the number of branches instead of undesired side reactions, and that the branch structures are well controlled. In addition, the analysis of the polymer structure reveals that the majority of HBPs have structures close to the ideal one. The simulation also suggested the slight dependence of branch density on molecular weight, which was experimentally confirmed by synthesizing HBPs with an evolmer having phenyl group.
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Affiliation(s)
- Masatoshi Tosaka
- Kyoto University - Uji Campus: Kyoto Daigaku - Uji Campus, Institute for Chemical Research, JAPAN
| | - Hinako Takeuchi
- Kyoto University - Uji Campus: Kyoto Daigaku - Uji Campus, Institute for Chemical Research, JAPAN
| | - Masato Kibune
- Kyoto University - Uji Campus: Kyoto Daigaku - Uji Campus, Institute for Chemical Research, JAPAN
| | - Tianxiang Tong
- Kyoto University - Uji Campus: Kyoto Daigaku - Uji Campus, Institute for Chemical Research, JAPAN
| | - Nanyi Zhu
- Kyoto University - Uji Campus: Kyoto Daigaku - Uji Campus, Institute for Chemical Research, JAPAN
| | - Shigeru Yamago
- Kyoto University, Institute for Chemnical Research, Gokashou, 611-0011, Uji, JAPAN
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Nascimento Batista JM, Sinhoreti MAC, Alves Fraga MA, Manoel da Silva MV, Correr AB, Roulet JF, Geraldeli S. Effect of preheating on mechanical properties of a resin-based composite containing elastomeric urethane monomer. J Mech Behav Biomed Mater 2023; 141:105758. [PMID: 36934689 DOI: 10.1016/j.jmbbm.2023.105758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/02/2023] [Accepted: 03/03/2023] [Indexed: 03/08/2023]
Abstract
This study investigated the effect of preheating an elastomeric urethane monomer (Exothane-24) experimental resin composite on its physicochemical properties. Two resin matrices were formulated: (a) 50 wt% Bisphenol-glycidyl methacrylate (Bis-GMA) and 50 wt% triethylene glycol dimethacrylate (TEGDMA); and (b) 20 wt% Exothane-24, 40 wt% Bis-GMA and 40 wt% TEGDMA. A photoinitiator system (0.25 wt% camphorquinone and 0.50 wt% ethyl-4-dimethylamino benzoate) and 65 wt% of the inorganic filler (20 wt% 0.05 μm silica and 80 wt% 0.7 μm BaBSiO2 glass) were added to both matrices. These formulations were then assigned to four groups: Exothane-24 (E); Exothane-24 plus preheating (EH); no Exothane-24 (NE); and no Exothane-24 plus preheating (NEH). NEH and EH were preheated at 69 °C. The dependent variables were as follows: film thickness (FT); polymerization shrinkage stress (PSS); gap width (GW); maximum rate of polymerization (Rpmax); and degree of conversion (DC). Data were statistically analyzed by two-way ANOVA and Tukey's test (α = 0.05). Preheating reduced FT for both composites. PSS and GW were significantly lower for EH, when compared with E. The DC for EH and NEH and the Rpmax for EH increased significantly. Preheating improved most of the physicochemical properties (FT, PSS, GW, and DC) of the experimental resin composite containing Exothane-24.
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Affiliation(s)
- João Marcos Nascimento Batista
- Department of Restorative Dentistry, Dental Materials Division, Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil
| | - Mário Alexandre Coelho Sinhoreti
- Department of Restorative Dentistry, Dental Materials Division, Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil.
| | - May Anny Alves Fraga
- Department of Restorative Dentistry, Dental Materials Division, Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil
| | - Marcus Vinícius Manoel da Silva
- Department of Restorative Dentistry, Dental Materials Division, Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil
| | - Américo Bortolazzo Correr
- Department of Restorative Dentistry, Dental Materials Division, Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil
| | - Jean-François Roulet
- Department of Restorative Dental Science, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - Saulo Geraldeli
- Division of Biomedical Materials, School of Dental Medicine, East Carolina University, Greenville, NC, USA
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Yang J, Silikas N, Watts DC. Polymerization and shrinkage kinetics and fracture toughness of bulk-fill resin-composites. Dent Mater 2022; 38:1934-1941. [PMID: 38709119 DOI: 10.1016/j.dental.2022.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 10/14/2022] [Accepted: 10/14/2022] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To determine degree of conversion (DC), maximum polymerization rate (RPmax), polymerization shrinkage (PS), maximum shrinkage rate (PS Rmax) and fracture toughness (KIC) of different types of bulk-fill (BF) composites plus the effect of viscosity reduction techniques. METHODS BF specimens were created in 2 mm deep molds: SonicFill 3 (SF3), Viscalor (VC), One Bulk Fill (OBF) and Beautifil Bulk (BBR). SF3 was applied via sonic insertion using a SonicFill handpiece (Kerr Corp. USA). Viscalor was pre-heated in a Caps Warmer in T3 mode (at 68 °C) for 30 s (T3-30 s) and 3 min (T3-3 min), respectively. Specimens were irradiated at zero distance from the upper surface with an Elipar S10 LED unit (3 M ESPE, USA) of mean irradiance 1200 mW/cm2 for 40 s. Real-time polymerization kinetics and DC at 5 min and 24 h post-irradiation (DC5 min and DC24 h) were measured using ATR-FTIR (n = 3). PS was measured up to 1 h on 1 mm thick discs via the bonded-disk technique (n = 3) and PS Rmax obtained by numerical differentiation (n = 3). For fracture toughness, single-edge-notched specimens (32 × 6 ×3 mm) of each BF composite were prepared and measured by three-point bending after 7 d water storage (n = 5). Data were analysed using One-way ANOVA, independent T-tests and Tukey post-hoc tests (p < 0.05). RESULTS SF3 showed the significantly highest DC5 min, DC24 h and RPmax (p < 0.05), followed by OBF (p < 0.05). Regardless of pre-heating, VC showed comparable conversion kinetics to BBR (p > 0.05). There was no significant difference in PS of these BF composites, except OBF had the highest PS (p > 0.05). However, PS Rmax significantly varied among materials (p = 0.047) and SF3 had the highest PS Rmax. Regarding fracture toughness, BBR had the lowest KIC (p < 0.05), whereas other composites showed similar KIC (p > 0.05). Strong correlations of filler content (wt%)-PS/KIC were found. Different pre-heating times had no significant influences on DC %, RPmax, PS, PS Rmax and KIC of VC (p > 0.05). SIGNIFICANCE Different types of bulk-fill composites showed comparable shrinkage. A highly filled BF giomer composite (BBR) had the lowest fracture toughness, whereas others had similar KIC. Pre-heating had no adverse effects on Viscalor properties. Sonication and pre-heating are beneficial techniques to enhance composite flowability without either increasing shrinkage or reducing fracture toughness.
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Affiliation(s)
- Jiawei Yang
- School of Medical Sciences, University of Manchester, Manchester, UK
| | - Nick Silikas
- School of Medical Sciences, University of Manchester, Manchester, UK
| | - David C Watts
- School of Medical Sciences, University of Manchester, Manchester, UK; Photon Science Institute, University of Manchester, Manchester, UK.
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Labrie D, Price RB, Sullivan B, Salazar AM, Gautam D, Stansbury JW, Ferracane JL. Effect of thickness on the degree of conversion of two bulk-fill and one conventional posterior resin-based composites at high irradiance and high temporal resolution. J Mech Behav Biomed Mater 2022; 136:105489. [PMID: 36206689 DOI: 10.1016/j.jmbbm.2022.105489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 09/22/2022] [Accepted: 09/24/2022] [Indexed: 11/30/2022]
Abstract
OBJECTIVES This study: 1) measures the effect of sample thickness and high irradiance on the depth-dependent time delay before photopolymerization reaction onset; 2) determines if exposure reciprocity exists; 3) measures the conversion rate at four irradiance levels; 4) determines the time, t0, at which the maximum DC rate is reached for two bulk-fill and one conventional posterior resin-based composites (RBCs). METHODS Tetric PowerFill IVA shade (Ivoclar Vivadent) and Aura bulk-fill ultra universal restorative (SDI), and one conventional posterior resin-based composite (RBC), Heliomolar A3 (Ivoclar Vivadent), that were either 0.2 mm, 2 mm, or 4 mm thick were photocured using a modified Bluephase G4 (Ivoclar Vivadent) light-curing unit (LCU) that delivered a single emission band (wavelength centered at 449 nm). The same radiant exposure of 24 J/cm2 was delivered at irradiances ranging from 0.5 to 3 W/cm2 by adjusting the exposure time. PowerFill was also photocured for 3 s or 6 s using a Bluephase PowerCure LCU (Ivoclar Vivadent) on the 3 s mode setting. The degree of conversion (DC) was measured in real-time at a high temporal resolution at 30 °C using Attenuated Total Reflection (ATR) FTIR spectroscopy with a sampling rate of 13 DC data points per second. The DC data were analyzed using a phenomenological autocatalytic model. The RBC viscosity was measured at 21 °C and 30 °C. Light transmission through the RBC samples at 22 °C was monitored with time to calculate the extinction coefficients of the RBCs. RESULTS The time delay before photopolymerization started increased as the RBC thickness increased and the irradiance decreased. An autocatalytic model described the DC data. The time t0 was less than 77 ms for the 0.2 mm thick samples of PowerFill irradiated using the highest irradiance of 3 W/cm2. Among the three RBCs for each sample thickness and irradiance level, the PowerFill had the smallest time t0. There was a time delay of 0.59 s and 1.25 s before the DC started to increase at the bottom of 4 mm thick samples for the PowerFill and Aura, respectively, when an irradiance of 1 W/cm2 was delivered. The time delay increased to 3.65 s for the Aura when an irradiance of 0.5 W/cm2 was delivered. The extinction coefficients near 449 nm were 0.78 mm-1, 0.76 mm-1, and 1.55 mm-1 during the first 2 s after the start of photocuring of PowerFill, Aura, and Heliomolar, respectively. Only PowerFill followed exposure reciprocity. At T = 30 °C, the viscosity was 3400, 17000, and 5200 Paˑs for PowerFill, Aura, and Heliomolar, respectively. SIGNIFICANCE The time delay between when photopolymerization starts at the top and bottom of 2- or 4-mm thick RBC restorations may affect the structural integrity of the bond between the tooth and the bottom of the restoration. Only PowerFill followed exposure reciprocity between irradiance levels of 0.5 to 3 W/cm2. Exposure reciprocity did not occur for Aura or Heliomolar, neither of which are optimized for short light exposure or high irradiance conditions.
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Affiliation(s)
- Daniel Labrie
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada.
| | - Richard B Price
- Department of Dental Clinical Sciences, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada
| | - Braden Sullivan
- Department of Dental Clinical Sciences, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada
| | - Austyn M Salazar
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO, 80309-0596, United States
| | - Dixa Gautam
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO, 80309-0596, United States
| | - Jeffrey W Stansbury
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO, 80309-0596, United States; Department of Craniofacial Biology, School of Dental Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - Jack L Ferracane
- Department of Restorative Dentistry, Oregon Health & Science University, Portland, OR, United States
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Oh HJ, Lee CH, Lee IB. Real-time measurement of transmittance changes during photo-polymerization of conventional and bulk-fill composites. Dent Mater J 2022; 41:800-807. [PMID: 35858790 DOI: 10.4012/dmj.2022-009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This study investigated transmittance changes during photo-polymerization of composites in real-time. The transmittance changes of one conventional micro-hybrid, three conventional nano-hybrid, and four bulk-fill composites were measured before, during, and after photo-polymerization, and the maximum rate of transmittance change was compared with that of polymerization shrinkage. A significant difference in transmittance of composite between before and after photo-polymerization was observed. The transmittance of composites except for one bulk-fill composite increased during photo-polymerization. There was a correlation between the maximum rate of transmittance change and the maximum rate of polymerization shrinkage. The transmittance analysis of composites gives very important information to know for the final aesthetic restoration and allows to evaluate polymerization kinetics.
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Affiliation(s)
- Hyun-Jin Oh
- Department of Conservative Dentistry and Dental Research Institute, School of Dentistry, Seoul National University
| | - Chang-Ha Lee
- Department of Conservative Dentistry and Dental Research Institute, School of Dentistry, Seoul National University
| | - In-Bog Lee
- Department of Conservative Dentistry and Dental Research Institute, School of Dentistry, Seoul National University
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Bendes ÁÁ, Kursula P, Kursula I. Structure and function of an atypical homodimeric actin capping protein from the malaria parasite. Cell Mol Life Sci 2022; 79:125. [PMID: 35132495 DOI: 10.1007/s00018-021-04032-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/28/2021] [Accepted: 11/09/2021] [Indexed: 11/27/2022]
Abstract
Apicomplexan parasites, such as Plasmodium spp., rely on an unusual actomyosin motor, termed glideosome, for motility and host cell invasion. The actin filaments are maintained by a small set of essential regulators, which provide control over actin dynamics in the different stages of the parasite life cycle. Actin filament capping proteins (CPs) are indispensable heterodimeric regulators of actin dynamics. CPs have been extensively characterized in higher eukaryotes, but their role and functional mechanism in Apicomplexa remain enigmatic. Here, we present the first crystal structure of a homodimeric CP from the malaria parasite and compare the homo- and heterodimeric CP structures in detail. Despite retaining several characteristics of a canonical CP, the homodimeric Plasmodium berghei (Pb)CP exhibits crucial differences to the canonical heterodimers. Both homo- and heterodimeric PbCPs regulate actin dynamics in an atypical manner, facilitating rapid turnover of parasite actin, without affecting its critical concentration. Homo- and heterodimeric PbCPs show partially redundant activities, possibly to rescue actin filament capping in life cycle stages where the β-subunit is downregulated. Our data suggest that the homodimeric PbCP also influences actin kinetics by recruiting lateral actin dimers. This unusual function could arise from the absence of a β-subunit, as the asymmetric PbCP homodimer lacks structural elements essential for canonical barbed end interactions suggesting a novel CP binding mode. These findings will facilitate further studies aimed at elucidating the precise actin filament capping mechanism in Plasmodium.
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Sullivan B, Kalliecharan D, Kostylev I, Earle G, Stansbury JW, Price RB, Labrie D. Photo- polymerization kinetics of a dental resin at a high temporal resolution. J Mech Behav Biomed Mater 2021; 124:104884. [PMID: 34638087 DOI: 10.1016/j.jmbbm.2021.104884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 09/28/2021] [Accepted: 10/04/2021] [Indexed: 10/20/2022]
Abstract
OBJECTIVES This study: 1) aims to measure with high temporal resolution the intrinsic rate of the degree of conversion (DC) of a dental resin-based composite (RBC) photo-cured at two irradiances; 2) aims to determine the transition time at which the DC rate is maximum; 3) used two different irradiances to measure the shift in transition time; 4) aims to compare transition times measured using DC and shrinkage strain. METHODS Samples (n = 20) 1 mm thick by 10 mm diameter of Filtek One bulk-fill restorative A2 shade (3M Oral Care) were photocured for 20 s with a single emission peak (wavelength centered at 455 nm) light-emitting-diode-based light-curing unit at irradiance levels of 890 mW/cm2 and 209 mW/cm2, and initial sample temperature of T = 23 °C. The DC was measured in real-time using Attenuated Total Reflection (ATR) FTIR spectroscopy with a sampling rate of 13 DC data points per second. The data were analyzed within a phenomenological autocatalytic model. In addition, the axial shrinkage strain was measured using 3 samples of the RBC with the same outer dimensions and under similar experimental conditions using the bonded disk method and an interferometric technique. RESULTS For the 890 mW/cm2 and 209 mW/cm2 irradiance levels, the DC with time was found to agree with the model enabling the determination of transition times of 0.66 ± 0.05 s and 2.3 ± 0.2 s, and the DC at these times of 5.5 ± 0.2% and 6.4 ± 0.2%. The maximum linear strain rate at 0.76 ± 0.01 s and 1.98 ± 0.02 s for the 890 mW/cm2 and 209 mW/cm2 irradiance levels, respectively, are within two standard deviations of the corresponding transition times. SIGNIFICANCE At an irradiance level much greater than 1000 mW/cm2, the photo-polymerization kinetics of a dental RBC may be too fast to be measured accurately using ATR-FTIR spectroscopy. A viable alternative to monitor the kinetics is through the measurements of the axial shrinkage strain employing the bonded disk method and an interferometric technique.
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Affiliation(s)
- Braden Sullivan
- Department of Dental Clinical Sciences, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada
| | - David Kalliecharan
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada
| | - Ivan Kostylev
- Quantum Dynamics Unit, Okinawa Institute of Science and Technology, Tancha 1919-1, Okinawa, 904-0495, Japan
| | - Guy Earle
- IObIO Inc., 1676 Edward Street, Halifax, Nova Scotia, B3H 3J3, Canada
| | - Jeffrey W Stansbury
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, United States; Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO, 80309-0596, United States
| | - Richard B Price
- Department of Dental Clinical Sciences, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada
| | - Daniel Labrie
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada.
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Wu Y, Raju C, Hou Z, Si Z, Xu C, Pranantyo D, Marimuthu K, De PP, Ng OT, Pethe K, Kang ET, Chan-Park MB. Mixed-charge pseudo-zwitterionic copolymer brush as broad spectrum antibiofilm coating. Biomaterials 2021; 273:120794. [PMID: 33887644 DOI: 10.1016/j.biomaterials.2021.120794] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 03/22/2021] [Accepted: 03/28/2021] [Indexed: 01/30/2023]
Abstract
Zwitterionic polymers are classical antifouling polymers but they require specialized monomers that have cationic and anionic charges integrated into a single monomer. Herein, we show that pseudo-zwitterionic copolymers synthesized from a mixture of 2 monomers each having a single opposite polarity has excellent antibiofilm efficacy. We have discovered a new mixed-charge copolymer brush (#1-A) synthesized from 2 oppositely charged monomers, the anionic SPM (3-Sulfopropyl methacrylate) and the cationic AMPTMA ((3-Acrylamidopropyl) trimethylammonium chloride), that achieves broad spectrum in vitro antibiofilm effect of greater than 99% reductions against all six Gram-positive and Gram-negative bacteria tested. In the murine subcutaneous wound catheter infection models, the #1-A has good long-term anti-biofilm efficacy against MRSA and Pseudomonas aeruginosa of 3.41 and 3.19 orders respectively, outperforming previous mixed-charge copolymer coatings. We discovered a new method to choose the cationic/anionic pair combination to form the best antibiofilm copolymer brush coating by exploiting the solution polymerization kinetics disparity between the cationic and anionic monomers. We also showed that #1-A is softer and has higher hydration than the classical zwitterionic polymer. This study shows the possibility of achieving potent antibiofilm efficacy by combining readily available opposite singly charged monomers.
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Barcelos LM, Borges MG, Soares CJ, Menezes MS, Huynh V, Logan MG, Fugolin APP, Pfeifer CS. Effect of the photoinitiator system on the polymerization of secondary methacrylamides of systematically varied structure for dental adhesive applications. Dent Mater 2020; 36:468-477. [PMID: 32005546 PMCID: PMC7200046 DOI: 10.1016/j.dental.2020.01.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 01/08/2020] [Accepted: 01/19/2020] [Indexed: 11/17/2022]
Abstract
OBJECTIVE The aim of this study was to investigate the influence of the photoinitiator system on the polymerization kinetics of methacrylamide-based monomers as alternatives to methacrylates in adhesives dental-based materials. METHODS In total, 16 groups were tested. Monofunctional monomers (2-hydroxyethyl methacrylate) - HEMA; (2-hydroxy-1-ethyl methacrylate) -2EMATE, (2-hydroxyethyl methacrylamide) - HEMAM; and (N-(1-hydroxybutan-2-yl) methacrylamide) -2EM; were combined with bifunctional monomers containing the same polymerizing moieties as the monofunctional counterparts (HEMA-BDI; 2EMATE-BDI; HEMAM-BDI; and 2EM-BDI) at 50/50 M ratios. BHT was used as inhibitor (0.1 wt%) and the photoinitiators used were: CQ + EDMAB (0.2/0.8), BAPO (0.2), IVOCERIN (0.2), and DMPA (0.2), in wt%. The polymerization kinetics were monitored using Near-IR spectroscopy (∼6165 cm-1) in real-time while the specimens were photoactivated with a mercury arc lamp (Acticure 2; 320-500 nm, 300 mW/cm2) for 5 min, and maximum rate of polymerization (Rpmax, in %.s-̄1), degree of conversion at Rpmax (DC@Rpmax, in %), and the final degree of conversion (Final DC, in %) were calculated (n = 3). Initial viscosity was measured with an oscillating rheometer (n = 3). Data were analyzed using Two-way ANOVA for the polymerization kinetics and one-way ANOVA for the viscosity. Multiple comparisons were made using the Tukey's test (∝ = 0.05). RESULTS There was statistically significant interaction between monomer and photoinitiator (p < 0.001). For the methacrylates groups, the highest Rpmax was observed for HEMA + DMPA and 2EMATE + BAPO. For methacrylamides groups, the highest Rpmax were observed for HEMAM and 2EM, both with DMPA. Final DC was higher for the methacrylate groups, in comparison with methacrylamide groups, independent of the photoinitiators. However, for the methacrylamide groups, the association with BAPO led to the lowest values of DC. In terms of DC@Rpmax, methacrylate-based systems showed significantly higher values than methacrylamide formulations. DMPA and Ivocerin led to higher values than CQ/EDMAB and BAPO in methacrylamide-based compounds. BAPO systems showed de lowest values for both HEMA and HEMAM formulations. For the viscosity (Pa.s), only 2EM had higher values (1.60 ± 0.15) in comparison with all monomers. In conclusion, polymerization kinetics was affected by the photoinitiators for both monomers. Viscosity was significantly increased with the use of secondary methacrylamide. SIGNIFICANCE this work demonstrated the feasibility of using newly-synthesized methacrylamide monomers in conjunction with a series of initiator systems already used in commercial materials.
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Affiliation(s)
- L M Barcelos
- Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlandia, Brazil
| | - M G Borges
- Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlandia, Brazil
| | - C J Soares
- Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlandia, Brazil
| | - M S Menezes
- Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlandia, Brazil
| | - V Huynh
- Department of Restorative Dentistry, Biomaterials and Biomechanics, School of Dentistry, Oregon Health & Science University, United States
| | - M G Logan
- Department of Restorative Dentistry, Biomaterials and Biomechanics, School of Dentistry, Oregon Health & Science University, United States
| | - A P P Fugolin
- Department of Restorative Dentistry, Biomaterials and Biomechanics, School of Dentistry, Oregon Health & Science University, United States
| | - C S Pfeifer
- Department of Restorative Dentistry, Biomaterials and Biomechanics, School of Dentistry, Oregon Health & Science University, United States.
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Wang R, Liu H, Wang Y. Different depth-related polymerization kinetics of dual-cure, bulk-fill composites. Dent Mater 2019; 35:1095-1103. [PMID: 31126623 DOI: 10.1016/j.dental.2019.05.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 04/26/2019] [Accepted: 05/03/2019] [Indexed: 10/26/2022]
Abstract
OBJECTIVE The aim of this study was to evaluate the polymerization kinetics qualitatively and quantitatively for dual-cure bulk-fill composites in comparison with light-cure bulk-fill and traditional incremental composites at two clinically relevant depths. METHODS Five commercial dental composites were evaluated, including three dual-cure bulk-fill composites (BulkEZ, HyperFIL and Injectafil), one light-cure bulk-fill composite Filtek Bulk Fill Flowable (FBF) and one traditional incremental composite Filtek Z250 (Z250) as controls. Specimens were prepared in two different depths (0.5 mm and 5 mm) for 20 s light irradiation. Self-cure was also evaluated for the three dual-cure composites. The polymerization kinetics were measured continuously in real-time for at least 10 min using a Fourier-transform infrared spectroscopy (FTIR) with an attenuated total reflectance (ATR) accessory. The experimental kinetic data were fitted using two mathematical models - a sigmoidal function and a superposition of two exponential functions characterizing the gel phase and glass phase. The degree of conversion (DC) and the rate of polymerization were calculated for all test conditions. RESULTS Both experimental FTIR measurements and mathematical modeling revealed distinct depth-related polymerization kinetics for BulkEZ compared to the other two dual-cure composites. Specifically, BulkEZ exhibited moderately-paced polymerization kinetics at both depths while HyperFIL and Injectafil exhibited faster polymerization at 0.5 mm and slower polymerization at 5 mm. The bulk-fill FBF and incremental Z250 exhibited relatively fast polymerization at both depths, a characteristic for light-cure. The DC values at the two depths were not significantly different for BulkEZ, but significantly higher at 0.5 mm than at 5 mm for the other four composites (α = 0.05). SIGNIFICANCE Polymerization kinetics and their depth variation for dual-cure bulk-fill composites are material dependent. The distinct depth-related polymerization kinetics revealed for BulkEZ compared to other composites may affect their contraction stress and clinical performance.
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Affiliation(s)
- Rong Wang
- Department of Oral and Craniofacial Sciences, University of Missouri-Kansas City, School of Dentistry, Kansas City, MO, USA
| | - Hang Liu
- Department of Oral and Craniofacial Sciences, University of Missouri-Kansas City, School of Dentistry, Kansas City, MO, USA
| | - Yong Wang
- Department of Oral and Craniofacial Sciences, University of Missouri-Kansas City, School of Dentistry, Kansas City, MO, USA.
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Fugolin AP, Dobson A, Mbiya W, Navarro O, Ferracane JL, Pfeifer CS. Use of (meth)acrylamides as alternative monomers in dental adhesive systems. Dent Mater 2019; 35:686-696. [PMID: 30826074 PMCID: PMC6462417 DOI: 10.1016/j.dental.2019.02.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 01/31/2019] [Accepted: 02/07/2019] [Indexed: 10/27/2022]
Abstract
OBJECTIVES Methacrylamides are proposed as components for dental adhesive systems with enhanced resistance to hydrolytic and enzymatic degradation. The specific objective of this study was to evaluate the polymerization kinetics, water sorption and solubility, pH-derived degradation and microtensile bond strength of various monofunctional acrylamides and meth(acrylamides) when copolymerized with dimethacrylates. METHODS Base monomers were added at 60 wt%, and included either BisGMA or UDMA. Monofunctional monomers were added at 40 wt%, including one (meth)acrylate as the control, two secondary methacrylamides and two tertiary acrylamides. DMPA (0.2 wt%) and DPI-PF6 (0.4 wt%)/BHT (0.1 wt%) were added as initiators/inhibitor. Polymerization kinetics wwere followed with near-IR spectroscopy in real time. Water sorption (WS) and solubility (SL) were measured following ISO 4049. Monomer degradation at different pH levels was assessed with 1H NMR. Microtensile bond strength (MTBS) was assessed in caries-free human third molars 48 h and 3 weeks after restorations were placed using solvated BisGMA-based adhesives (40 vol% ethanol). Data were analyzed with one-way ANOVA/Tukey's test (α = 0.05). RESULTS As expected, rate of polymerization and final degree of conversion (DC) were higher for the acryl versions of each monomer, and decreased with increasing steric hindrance around the vinyl group for each molecule. In general, UDMA copolymerizations were more rapid and extensive than for BisGMA, but this was dependent upon the specific monofunctional monomer added. WS/SL were in general higher for the (meth)acrylamides compared to the (meth)acrylates, except for the tertiary acrylamide, which showed the lowest values. One of the secondary methacrylamides was significantly more stable than the methacrylate control, but the alpha substitutions decreased stability to degradation in acid pH. MTBS in general was higher for the (meth)acrylates. While for all materials the MTBS values at 3 weeks decreased in relation to the 24 h results, the tertiary acrylamide showed no reduction in bond strength. SIGNIFICANCE This study highlights the importance of considering steric and electronic factors when designing monomers for applications where rapid polymerizations are needed, especially when co-polymerizations with other base monomers are required to balance mechanical properties, as is the case with dental adhesives. The results of this investigation will be used to design fully formulated adhesives to be tested in clinically-relevant conditions.
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Affiliation(s)
- Ana P Fugolin
- Department of Restorative Dentistry, Division of Biomaterials and Biomechanics, Oregon Health & Science University, Portland, OR, USA
| | - Adam Dobson
- Department of Restorative Dentistry, Division of Biomaterials and Biomechanics, Oregon Health & Science University, Portland, OR, USA
| | - Wilbes Mbiya
- Department of Restorative Dentistry, Division of Biomaterials and Biomechanics, Oregon Health & Science University, Portland, OR, USA
| | - Oscar Navarro
- Department of Restorative Dentistry, Division of Biomaterials and Biomechanics, Oregon Health & Science University, Portland, OR, USA
| | - Jack L Ferracane
- Department of Restorative Dentistry, Division of Biomaterials and Biomechanics, Oregon Health & Science University, Portland, OR, USA
| | - Carmem S Pfeifer
- Department of Restorative Dentistry, Division of Biomaterials and Biomechanics, Oregon Health & Science University, Portland, OR, USA.
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Par M, Tarle Z, Hickel R, Ilie N. Polymerization kinetics of experimental bioactive composites containing bioactive glass. J Dent 2018; 76:83-88. [PMID: 29935997 DOI: 10.1016/j.jdent.2018.06.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 05/14/2018] [Accepted: 06/20/2018] [Indexed: 10/28/2022] Open
Abstract
OBJECTIVES To investigate the polymerization kinetics and the degree of conversion (DC) of experimental resin composites with varying amount of bioactive glass 45S5 (BG). METHODS Experimental resin composites based on a photo-curable Bis-GMA/TEGDMA resin system were prepared. The composite series contained 0, 5, 10, 20, and 40 wt% of BG and reinforcing fillers up to the total filler amount of 70 wt%. Composite specimens were light cured with 1219 mW/cm2 for 20 or 40 s and their DC was monitored during 5 min at the data collection rate of 2 s-1 using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). RESULTS The 5-min DC values for experimental composites were in the range of 42.4-55.9% and 47.3-57.9% for curing times of 20 and 40 s, respectively. The differences in the 5-min DC between curing times of 20 s or 40 s became more pronounced in materials with higher BG amount. Within both curing times, a decreasing trend of the 5-min DC values was observed with the increasing percentage of BG fillers. The maximum polymerization rate also decreased consistently with the increasing BG amount. CONCLUSIONS Unsilanized BG fillers showed a dose-dependent inhibitory effect on polymerization rate and the DC. Extending the curing time from 20 to 40 s showed a limited potential to improve the DC of composites with higher BG amount. SIGNIFICANCE The observed inhibitory effect of BG fillers on the polymerization of resin composites may have a negative influence on mechanical properties and biocompatibility.
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Affiliation(s)
- Matej Par
- Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Gunduliceva 5, Zagreb, Croatia.
| | - Zrinka Tarle
- Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Gunduliceva 5, Zagreb, Croatia.
| | - Reinhard Hickel
- Department of Restorative Dentistry, Periodontology and Pedodontics, Ludwig-Maximilians-University of Munich, Goethestr. 70, Munich, Germany.
| | - Nicoleta Ilie
- Department of Restorative Dentistry, Periodontology and Pedodontics, Ludwig-Maximilians-University of Munich, Goethestr. 70, Munich, Germany.
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Li YJ, Barthès-Biesel D, Salsac AV. Polymerization kinetics of a mixture of Lipiodol and Glubran 2 cyanoacrylate glue upon contact with a proteinaceous solution. J Mech Behav Biomed Mater 2017; 74:84-92. [PMID: 28554038 DOI: 10.1016/j.jmbbm.2017.05.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 05/13/2017] [Accepted: 05/16/2017] [Indexed: 02/03/2023]
Abstract
The Glubran 2 cyanoacrylate glue is a liquid embolic agent used to block blood vessels endovascularly. Typically mixed with an iodized oil (Lipiodol) for visualization under X-ray, it polymerizes when in contact with blood and tissues owing to the presence of ions and proteins. The objective of the study is to determine the influence of plasma proteins in the polymerization reaction. A triggering solution containing bovine serum albumin (BSA) and the main blood ions is used as a model of plasma. The polymerization kinetics of Glubran 2-Lipiodol mixtures is measured upon aspiration in a capillary tube and contact with the proteinaceous solution. Having varied the glue and protein concentrations, we show that glue-Lipiodol mixtures with concentrations larger or equal to 25% polymerize when put in contact with an ionic solution containing at least 4% of BSA. The reaction is decomposed into two phases: a fast zwitterionic polymerization induced by the BSA molecules followed by a slower polymerization phase. The reaction speed and extent of the solidification region mostly depend on the glue concentration. The time for the glue solution to polymerize over a 1mm thickness varies from 5s for pure glue to about 1min for a 50% glue concentration, and 10min for a 25% glue mixture. It is the first time that the kinetics of the two polymerization reactions is quantified for Glubran 2, which will provide the information needed by interventional radiologists to optimize the planning of endovascular glue injection.
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Affiliation(s)
- Y J Li
- Biomechanics and Bioengineering Laboratory (UMR CNRS 7338), Université de Technologie de Compiègne - CNRS, Sorbonne Universités, CS 60319, 60203 Compiègne, France
| | - D Barthès-Biesel
- Biomechanics and Bioengineering Laboratory (UMR CNRS 7338), Université de Technologie de Compiègne - CNRS, Sorbonne Universités, CS 60319, 60203 Compiègne, France
| | - A-V Salsac
- Biomechanics and Bioengineering Laboratory (UMR CNRS 7338), Université de Technologie de Compiègne - CNRS, Sorbonne Universités, CS 60319, 60203 Compiègne, France.
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Par M, Šantić A, Gamulin O, Marovic D, Moguš-Milanković A, Tarle Z. Impedance changes during setting of amorphous calcium phosphate composites. Dent Mater 2016; 32:1312-1321. [PMID: 27524232 DOI: 10.1016/j.dental.2016.07.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Accepted: 07/25/2016] [Indexed: 11/25/2022]
Abstract
OBJECTIVES To investigate the electrical properties of experimental light-curable composite materials based on amorphous calcium phosphate (ACP) with the admixture of silanized barium glass and silica fillers. METHODS Short-term setting was investigated by impedance measurements at a frequency of 1kHz, while for the long-term setting the impedance spectra were measured consecutively over a frequency range of 0.05Hz to 1MHz for 24h. The analysis of electrical resistivity changes during curing allowed the extraction of relevant kinetic parameters. The impedance results were correlated to the degree of conversion assessed by Raman spectroscopy, water content determined by gravimetry, light transmittance measured by CCD spectrometer and microstructural features observed by scanning electron microscopy. RESULTS ACP-based composites have shown higher immediate degree of conversion and less post-cure polymerization than the control composites, but lower polymerization rate. The polymerization rate assessed by impedance measurements correlated well with the light transmittance. The differences in the electrical conductivity values observed among the materials were correlated to the amount of water introduced into composites by the ACP filler. High correlation was found between the degree of conversion and electrical resistivity. Equivalent circuit modeling revealed two electrical contributions for the ACP-based composites and a single contribution for the control composites. SIGNIFICANCE The impedance spectroscopy has proven a valuable method for gaining insight into various features of ACP-based composites. Better understanding of the properties of ACP-based composites should further the development of these promising bioactive materials.
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Affiliation(s)
- Matej Par
- Private Dental Practice, Dankovecka 9, 10040 Zagreb, Croatia.
| | - Ana Šantić
- Glass Laboratory, Ruđer Bošković Institute, Zagreb, Croatia.
| | - Ozren Gamulin
- Department of Physics and Biophysics, School of Medicine, University of Zagreb, Salata 3b, Zagreb, Croatia.
| | - Danijela Marovic
- Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Gunduliceva 5, Zagreb, Croatia.
| | | | - Zrinka Tarle
- Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Gunduliceva 5, Zagreb, Croatia.
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Par M, Marovic D, Skenderovic H, Gamulin O, Klaric E, Tarle Z. Light transmittance and polymerization kinetics of amorphous calcium phosphate composites. Clin Oral Investig 2016; 21:1173-1182. [PMID: 27315056 DOI: 10.1007/s00784-016-1880-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 06/08/2016] [Indexed: 11/24/2022]
Abstract
OBJECTIVES This study investigated light transmittance and polymerization kinetics of experimental remineralizing composite materials based on amorphous calcium phosphate (ACP), reinforced with inert fillers. MATERIALS AND METHODS Light-curable composites were composed of Bis-EMA-TEGDMA-HEMA resin and ACP, barium glass, and silica fillers. Additionally, a commercial composite Tetric EvoCeram was used as a reference. Light transmittance was recorded in real-time during curing, and transmittance curves were used to assess polymerization kinetics. To obtain additional information on polymerization kinetics, temperature rise was monitored in real-time during curing and degree of conversion was measured immediately and 24 h post-cure. RESULTS Light transmittance values of 2-mm thick samples of uncured ACP composites (2.3-2.9 %) were significantly lower than those of the commercial composite (3.8 %). The ACP composites presented a considerable transmittance rise during curing, resulting in post-cure transmittance values similar to or higher than those of the commercial composite (5.5-7.9 vs. 5.4 %). The initial part of light transmittance curves of experimental composites showed a linear rise that lasted for 7-20 s. Linear fitting was performed to obtain a function whose slope was assessed as a measure of polymerization rate. Comparison of transmittance and temperature curves showed that the linear transmittance rise lasted throughout the most part of the pre-vitrification period. CONCLUSIONS The linear rise of light transmittance during curing has not been reported in previous studies and may indicate a unique kinetic behavior, characterized by a long period of nearly constant polymerization rate. CLINICAL RELEVANCE The observed kinetic behavior may result in slower development of polymerization shrinkage stress but also inferior mechanical properties.
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Affiliation(s)
- Matej Par
- Private Dental Practice, Dankovecka 9/I, Zagreb, Croatia.
| | - Danijela Marovic
- Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Gunduliceva 5, Zagreb, Croatia
| | | | - Ozren Gamulin
- Department of Physics and Biophysics, School of Medicine, University of Zagreb, Salata 3b, Zagreb, Croatia
| | - Eva Klaric
- Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Gunduliceva 5, Zagreb, Croatia
| | - Zrinka Tarle
- Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Gunduliceva 5, Zagreb, Croatia
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Selig D, Haenel T, Hausnerová B, Moeginger B, Labrie D, Sullivan B, Price RBT. Examining exposure reciprocity in a resin based composite using high irradiance levels and real-time degree of conversion values. Dent Mater 2015; 31:583-93. [PMID: 25804190 DOI: 10.1016/j.dental.2015.02.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 12/10/2014] [Accepted: 02/16/2015] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Exposure reciprocity suggests that, as long as the same radiant exposure is delivered, different combinations of irradiance and exposure time will achieve the same degree of resin polymerization. This study examined the validity of exposure reciprocity using real time degree of conversion results from one commercial flowable dental resin. Additionally a new fitting function to describe the polymerization kinetics is proposed. METHODS A Plasma Arc Light Curing Unit (LCU) was used to deliver 0.75, 1.2, 1.5, 3.7 or 7.5 W/cm(2) to 2mm thick samples of Tetric EvoFlow (Ivoclar Vivadent). The irradiances and radiant exposures received by the resin were determined using an integrating sphere connected to a fiber-optic spectrometer. The degree of conversion (DC) was recorded at a rate of 8.5 measurements a second at the bottom of the resin using attenuated total reflectance Fourier Transform mid-infrared spectroscopy (FT-MIR). Five specimens were exposed at each irradiance level. The DC reached after 170s and after 5, 10 and 15 J/cm(2) had been delivered was compared using analysis of variance and Fisher's PLSD post hoc multiple comparison tests (alpha=0.05). RESULTS The same DC values were not reached after the same radiant exposures of 5, 10 and 15 J/cm(2) had been delivered at an irradiance of 3.7 and 7.5 W/cm(2). Thus exposure reciprocity was not supported for Tetric EvoFlow (p<0.05). SIGNIFICANCE For Tetric EvoFlow, there was no significant difference in the DC when 5, 10 and 15J/cm(2) were delivered at irradiance levels of 0.75, 1.2 and 1.5 W/cm(2). The optimum combination of irradiance and exposure time for this commercial dental resin may be close to 1.5 W/cm(2) for 12s.
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Affiliation(s)
- Daniela Selig
- Dalhousie University, Department of Dental Clinical Sciences, Faculty of Dentistry, Halifax, Canada; Bonn-Rhein-Sieg University of Applied Sciences, Department of Natural Sciences, Rheinbach, Germany; FH Aachen University of Applied Sciences, Department of Natural Sciences, Jülich, Germany
| | - Thomas Haenel
- Dalhousie University, Department of Dental Clinical Sciences, Faculty of Dentistry, Halifax, Canada; Bonn-Rhein-Sieg University of Applied Sciences, Department of Natural Sciences, Rheinbach, Germany; Tomas Bata University in Zlin, Faculty of Technology, Department of Production Engineering, Zlin, Czech Republic; Tomas Bata University in Zlin, University Institute, Centre of Polymer Systems, Zlin, Czech Republic
| | - Berenika Hausnerová
- Tomas Bata University in Zlin, Faculty of Technology, Department of Production Engineering, Zlin, Czech Republic; Tomas Bata University in Zlin, University Institute, Centre of Polymer Systems, Zlin, Czech Republic
| | - Bernhard Moeginger
- Bonn-Rhein-Sieg University of Applied Sciences, Department of Natural Sciences, Rheinbach, Germany
| | - Daniel Labrie
- Dalhousie University, Department of Physics and Atmospheric Sciences, Halifax, Canada
| | - Braden Sullivan
- Dalhousie University, Department of Dental Clinical Sciences, Faculty of Dentistry, Halifax, Canada
| | - Richard B T Price
- Dalhousie University, Department of Dental Clinical Sciences, Faculty of Dentistry, Halifax, Canada.
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Randolph LD, Palin WM, Watts DC, Genet M, Devaux J, Leloup G, Leprince JG. The effect of ultra-fast photopolymerisation of experimental composites on shrinkage stress, network formation and pulpal temperature rise. Dent Mater 2014; 30:1280-9. [PMID: 25261362 DOI: 10.1016/j.dental.2014.09.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 09/03/2014] [Accepted: 09/03/2014] [Indexed: 11/22/2022]
Abstract
OBJECTIVES to complement our previous work by testing the null hypotheses that with short curing times and high DC, TPO-based resin composites would exhibit (1) higher polymerization stresses and consequently display (2) higher temperature rise and (3) higher flexural modulus, flexural strength and hardness, compared to a conventional CQ-based experimental composite. METHODS Two experimental resin composites using either Lucirin-TPO or camphorquinone/DMAEMA as photoinitiators were prepared. Light curing was carried out using spectral outputs adapted to the absorption properties of each initiator. Different irradiation protocols were selected (0.5, 1, 3, 9 s at 500, 1000 and 2000 mW/cm(2) for Lucirin-TPO based composites and 20 or 40 s at 1000 mW/cm2 for Lucirin-TPO and camphorquinone-based composites). Degree of conversion (DC) was measured in real time by means of FT-NIR spectroscopy. Pulpal temperature rise (ΔT) was studied in a tooth model. Polymerization stress was monitored using the Bioman instrument. For cured specimens, flexural modulus and flexural strength were determined using a three point bending platform and Vickers hardness was determined with a microhardness indentor on samples prior to and after 24 h incubation in 75/25 ethanol/H2O. Premolars were restored with both materials and microleakage at the teeth/composite interfaces following restoration was assessed. RESULTS Lucirin-TPO-based composites irradiated at radiant exposures of 3 J/cm(2) and more exhibited significantly higher DCs, associated with increased flexural moduli and hardness compared to CQ-based composites. For an ultra-short irradiation time of 1 s at 1000 mW/cm(2), TPO-composites displayed similar polymerization stresses compared to CQ-controls with yet a 25% increase for flexural modulus and 40% increase for hardness measured after EtOH/H2O sorption. Higher stress rates were however observed in all curing protocols compared to CQ-composites. Microleakage was similar between TPO and CQ-composites irradiated at 1000 mW/cm(2) for 3 and 20 s respectively, while a significant increase was observed for TPO-composites irradiated for 1 s. ΔT measured through a 0.6 mm thick dentin layer were all below 5.5°C; TPO-composites exhibited similar or lower values compared to controls. SIGNIFICANCE The use of Lucirin-TPO in resin composites along with appropriate curing conditions may allow for a major reduction of irradiation time while improving mechanical properties. The amount of stress observed during polymerization in TPO-based composites can be similar to those using CQ and the cohesion at the restoration-tooth interface was not affected by short curing times. Contrary to other studies, we found that the temperatures increases measured during polymerization were all well below the 5.5°C threshold for the pulp.
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Yamasaki LC, De Vito Moraes AG, Barros M, Lewis S, Francci C, Stansbury JW, Pfeifer CS. Polymerization development of "low-shrink" resin composites: Reaction kinetics, polymerization stress and quality of network. Dent Mater 2013; 29:e169-79. [PMID: 23849746 DOI: 10.1016/j.dental.2013.04.021] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 02/28/2013] [Accepted: 04/25/2013] [Indexed: 10/26/2022]
Abstract
OBJECTIVES To evaluate "low-shrink" composites in terms of polymerization kinetics, stress development and mechanical properties. METHODS "Low-shrink" materials (Kalore/KAL, N'Durance/NDUR, and Filtek P90/P90) and one control (Esthet X HD/EHD) were tested. Polymerization stress (PS) was measured using the Instron 5565 tensometer. Volumetric shrinkage (VS) was determined by the ACTA linometer. Elastic modulus (E) and flexural strength (FS) were obtained by a three-point bending test. Degree of conversion (DC) and polymerization rate (Rp) were determined by NIR spectroscopy (6165cm(-1) for dimethacrylates; 4156 and 4071cm(-1) for P90). Photopolymerization was performed at 740mW/cm(2)×27s. Glass transition temperature (Tg), degree of heterogeneity and crosslink density were obtained in a DMA for the fully cured specimens. Analysis of extracts was done by (1)H NMR. Data were analyzed with one-way ANOVA/Tukey's test (α=0.05). RESULTS The control presented the highest shrinkage and Tg. P90 showed the highest modulus, and NDUR demonstrated the highest conversion. The polymerization rates were comparable for all materials. NDUR and KAL had the highest and the lowest network homogeneity, respectively. The multifunctional P90 had the highest crosslink density, with no difference between other composites. The control had the greatest stress development, similar to NDUR. Crosslinking density and polymer network homogeneity were influenced by degree of conversion and monomer structure. SIGNIFICANCE Not all "low-shrink" composites reduced polymerization stress. P90 and NDUR had no leachable monomers, which was also a function of high crosslinking (P90) and high conversion (NDUR).
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Affiliation(s)
- Lilyan C Yamasaki
- Department of Biomaterials and Oral Biology, University of São Paulo, School of Dentistry, São Paulo, SP, Brazil.
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Faria-e-Silva AL, Piva E, Moraes RR. Time-dependent effect of refrigeration on viscosity and conversion kinetics of dental adhesive resins. Eur J Dent 2010; 4:150-5. [PMID: 20396445 PMCID: PMC2853827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
OBJECTIVES This study evaluated the effect of refrigeration at 4 degrees C and post-refrigeration times (immediate, 5, 10, 15, or 20 min) on the viscosity and conversion kinetics of adhesive bonding resins. METHODS Scotchbond Dual-Cure (3M ESPE) and Clearfil SE Bond (Kuraray) were tested. Control samples were kept at 25 degrees C for 24 h. At each post-refrigeration time, the temperature was checked with a K-type thermocouple. Viscosity measurements as a function of temperature were performed using a cone-plate viscometer. Real-time polymerization was monitored by infrared spectroscopy. Degree of conversion (DC) was calculated for each second during polymerization, and the rate of polymerization analyzed. Data were separately submitted to two-way ANOVA and Tukey's test (P<.05). RESULTS Clearfil presented faster increase in temperature after exposure to room temperature than Scotchbond. A continuous decrease in viscosity (Pa.s) was observed for both Scotchbond (0.49, 0.34, 0.30, 0.26, 0.23, 0.23) and Clearfil (0.38, 0.37, 0.34, 0.25, 0.24, 0.22). For Scotchbond, higher final DC was detected for the control (62.7%) compared with the immediate (53.3%) and 5 min (54.7%) groups. For Clearfil, the control sample (81.4%) showed higher DC than all refrigerated groups (68.8-69.5%). Clearfil always showed significantly higher DC than Scotchbond. CONCLUSIONS Refrigeration presented a significant time- and material-dependent effect on the viscosity and polymerization kinetics of the bonding resins. Under clinical conditions, adhesive agents should be removed from the refrigerator at least 20 min before being used.
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Affiliation(s)
- André L Faria-e-Silva
- Professor, Department of Dentistry, School of Dentistry, State University of Montes Claros, MG, Brasil,Corresponding author: Prof. André L. Faria-e-Silva, Department of Dentistry, School of Dentistry State University of Montes Claros, MG, Brazil Campus Universitário Prof. Darcy Ribeiro, Vila Mauricéia Montes Claros, MG, Brasil - 39401-089, Phone/Fax: +55 38 3229.8284, E-mail:
| | - Evandro Piva
- Department of Restorative Dentistry, School of Dentistry, Federal University of Pelotas, RS, Brasil
| | - Rafael R Moraes
- Department of Restorative Dentistry, School of Dentistry, Federal University of Pelotas, RS, Brasil
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Meunier F, Pichot C, Elaïssari A. Effect of thiol-containing monomer on the preparation of temperature-sensitive hydrogel microspheres. Colloid Polym Sci 2006; 284:1287-92. [PMID: 24058238 DOI: 10.1007/s00396-006-1514-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2006] [Accepted: 04/18/2006] [Indexed: 11/21/2022]
Abstract
The main objective of this study is to prepare, thermally, sensitive microgel particles bearing thiol groups via precipitation polymerization of N-isopropylacrylamide (NIPAM), methylenebisacrylamide (MBA) and vinylbenzylisothiouronium chloride (VBIC) using 2-2′-azobis(2-amidinopropane)-dihydrochloride (V50) as initiator. The influence of various parameters has been investigated as a systematic study to point out the role of each reactant on polymerization conversion, and consequently, on particles and water-soluble polymer formation. The final microgel particles were characterized with respect to particle size and swelling ability. The aim of this paper is to complete our first short communication; Macromolecular symposia, 2000. 150: p. 283–290.
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