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Fu D, Holles SB, England E, Zhang Y, Cheng S, Szczepanski C. Compatibility versus reaction diffusion: Factors that determine the heterogeneity of polymerized adhesive networks. Dent Mater 2024; 40:800-810. [PMID: 38485599 PMCID: PMC11098697 DOI: 10.1016/j.dental.2024.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 02/20/2024] [Accepted: 03/02/2024] [Indexed: 05/18/2024]
Abstract
OBJECTIVES Heterogeneity and phase separation during network polymerization is a major issue contributing to the failure of dental adhesives. This study investigates how the ratio of hydrophobic crosslinkers to hydrophilic comonomer (C/H ratio), as well as cosolvent fraction (ethanol/water) influences the degree of heterogeneity and proclivity for phase separation in a series of model adhesive formulations. METHODS Twelve formulations were investigated, with 4 different C/H ratios (7:1, 2.2:1, 1:1, 0.5:1) and 3 different overall cosolvent fractions (0, 10 and 20 wt%). The heterogeneity and phase behavior were characterized using Fourier Transform Infrared Spectroscopy (FT-IR), dynamic mechanical analysis (DMA), small-angle x-ray scattering (SAXS) and atomic force microscopy (AFM). RESULTS In resins without cosolvent, all characterizations confirm reduced heterogeneity as C/H ratio decreases. However, when 10 or 20 wt% of cosolvent is included in the adhesive formulation, a higher degree of heterogeneity and even distinct phase separation with domains ranging from a few hundreds of nanometers to a few micrometers in size form. This is particularly noticeable at lower C/H ratios, which is surprising as HEMA is commonly considered a compatibilizer between hydrophobic crosslinkers and aqueous (co)solvents. SIGNIFICANCE Our experiments demonstrate that formulations with lower C/H ratio and thus a lower viscosity experience later onsets of diffusion limitations during polymerization, which favors thermodynamically driven phase separation. Therefore, to determine or predict the resulting phase structure of adhesive materials, it is necessary to consider the kinetics and diffusion constraints during the formation of the polymer network and not just the compatibility of resin constituents.
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Affiliation(s)
- Denghao Fu
- Department of Chemical Engineering & Materials Science, Michigan State University, East Lansing MI 48824, USA
| | - Sarah Beth Holles
- Department of Chemical Engineering & Materials Science, Michigan State University, East Lansing MI 48824, USA
| | - Emily England
- Department of Chemical Engineering & Materials Science, Michigan State University, East Lansing MI 48824, USA
| | - Yunlu Zhang
- Department of Chemical Engineering & Materials Science, Michigan State University, East Lansing MI 48824, USA
| | - Shiwang Cheng
- Department of Chemical Engineering & Materials Science, Michigan State University, East Lansing MI 48824, USA
| | - Caroline Szczepanski
- Department of Chemical Engineering & Materials Science, Michigan State University, East Lansing MI 48824, USA.
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Stape THS, Mutluay M, Tezvergil-Mutluay A. To etch or not to etch, Part III: On the hydrophobic-rich content and fatigue strength of universal adhesives after long-term ageing. Dent Mater 2024; 40:44-52. [PMID: 37891131 DOI: 10.1016/j.dental.2023.09.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 09/28/2023] [Indexed: 10/29/2023]
Abstract
OBJECTIVES To examine whether dentin-etching extension and/or the hydrophobic-rich content of hybrid layers would affect fatigue strengths of a mild universal adhesive after long-term aging. METHODS Twin-bonded resin-dentin interfaces were produced by etching sound midcoronal dentin beams with 32 % ortho-phosphoric acid for 15 s (OPA15s), 3 s (OPA3s) or 10 % meta-phosphoric acid for 15 s (MPA15s). Samples were bonded with a mild universal adhesive with or without additional coating using a solvent-free bisGMA-based bonding resin. Self-etch application served as control. Composite buildups were made with a nanofilled composite. Bar-shaped twin-bonded interfaces (0.9 × 0.9 × 12 mm) were aged for two years in artificial saliva at 37 ℃ and tested under 4-point flexure at quasi-static (n = 16) and cyclic loads (n = 35) until failure. The stress-life fatigue behavior was evaluated using the staircase method at 4 Hz. Crack initiation and fracture patterns were evaluated by SEM. Cyclic-loaded data was analyzed by Kruskal-Wallis on Ranks (α = 0.05). RESULTS Significantly higher fatigue life distributions and higher endurance limits were observed for less aggressive etch-and-rinse protocols (OPA3s and MPA15s) after long-term ageing. Hydrophobic-rich coating produced 20-32 % higher endurance limits, prevented micrometer-sized porosities at bonded interfaces, reduced etching-associated variability and lowered crack formation. Significance Long-term hydrolysis produces detrimental effects on the fatigue strength of resin-dentin interfaces. The bond-promotion effect of less aggressive etch-and-rinse protocols and the creation of hybrid layers with higher hydrophobic-rich content are critical to extend the durability of mild universal adhesives. Therefore, current oversimplification trends in adhesive dentistry may limit resin-dentin bonding performance.
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Affiliation(s)
- Thiago Henrique Scarabello Stape
- Department of Restorative Dentistry and Cariology, Adhesive Dentistry Research Group, Institute of Dentistry, University of Turku, Turku, Finland; Turku University Hospital, TYKS, University of Turku, Turku, Finland.
| | - Murat Mutluay
- Department of Restorative Dentistry and Cariology, Adhesive Dentistry Research Group, Institute of Dentistry, University of Turku, Turku, Finland; Department of Prosthetic Dentistry, Institute of Dentistry, University of Eastern Finland, Kuopio, Finland
| | - Arzu Tezvergil-Mutluay
- Department of Restorative Dentistry and Cariology, Adhesive Dentistry Research Group, Institute of Dentistry, University of Turku, Turku, Finland; Turku University Hospital, TYKS, University of Turku, Turku, Finland
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Zhong Q, Zhou Q, Xiao T, Li X, Xu W, Li Y, Tao Y, Wu L, Zhou Z, Wong HM, Li QL. Er:YAG Laser Physical Etching and Ultra-High-Molecular-Weight Cross-Linked Sodium Polyacrylate Chemical Etching for a Reliable Dentin Dry Bonding. ACS APPLIED MATERIALS & INTERFACES 2023; 15:39127-39142. [PMID: 37565782 DOI: 10.1021/acsami.3c07091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Dentin bond interface stability is the key issue of dental adhesion in present clinical dentistry. The concept of selective extrafibrillar demineralization has opened a new way to maintain intrafibrillar minerals to prevent interface degradation. Here, using ultra-high-molecular-weight sodium polyacrylate [Carbopol (Carbo) > 40 kDa] as a calcium chelator, we challenge this concept and propose a protocol for reliable dentin dry bonding. The results of high-resolution transmission electron microscopy revealed periodic bands of 67 nm dentin collagen fibrils after Carbo etching, and the hydroxyproline concentration increasing with prolonged chelating time denied the concept of extrafibrillar demineralization. The results that wet and dry bonding with Carbo-based demineralization produced a weaker bond strength than the traditional phosphoric acid wet adhesion suggested that the Carbo-based demineralization is an unreliable adhesion strategy. A novel protocol of Er:YAG laser physical etching followed by Carbo chemical etching for dentin adhesion revealed that a micro-/nano-level rough, rigid, and non-collagen exposed dentin surface was produced, the micro-tensile bond strength was maintained after aging under dry and wet bonding modes, and in situ zymography and nanoleakage within the hybrid layers presented lower signals after aging. Cell culture in vitro and a rabbit deep dentin adhesion model in vivo proved that this protocol is safe and biocompatible. Taken together, the concept of extrafibrillar demineralization is limited and insufficient to use in the clinic. The strategy of Er:YAG laser physical etching followed by Carbo chemical etching for dentin adhesion produces a bonding effect with reliability, durability, and safety.
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Affiliation(s)
- Qi Zhong
- Key Lab. of Oral Diseases Research of Anhui Province, College & Hospital of Stomatology, Anhui Medical University, Hefei 230032, China
| | - Qingli Zhou
- Key Lab. of Oral Diseases Research of Anhui Province, College & Hospital of Stomatology, Anhui Medical University, Hefei 230032, China
| | - Ting Xiao
- Key Lab. of Oral Diseases Research of Anhui Province, College & Hospital of Stomatology, Anhui Medical University, Hefei 230032, China
| | - Xiaofeng Li
- Key Lab. of Oral Diseases Research of Anhui Province, College & Hospital of Stomatology, Anhui Medical University, Hefei 230032, China
| | - Wu Xu
- Key Lab. of Oral Diseases Research of Anhui Province, College & Hospital of Stomatology, Anhui Medical University, Hefei 230032, China
| | - Yuzhu Li
- Key Lab. of Oral Diseases Research of Anhui Province, College & Hospital of Stomatology, Anhui Medical University, Hefei 230032, China
| | - Yang Tao
- Key Lab. of Oral Diseases Research of Anhui Province, College & Hospital of Stomatology, Anhui Medical University, Hefei 230032, China
| | - Leping Wu
- Key Lab. of Oral Diseases Research of Anhui Province, College & Hospital of Stomatology, Anhui Medical University, Hefei 230032, China
| | - Zheng Zhou
- School of Dentistry, University of Detroit Mercy, Detroit, Michigan 48208-2576, United States
| | - Hai Ming Wong
- Faculty of Dentistry, The Prince Philip Dental Hospital, The University of Hong Kong, Hong Kong 999077, China
| | - Quan-Li Li
- Key Lab. of Oral Diseases Research of Anhui Province, College & Hospital of Stomatology, Anhui Medical University, Hefei 230032, China
- Department of Stomatology, Longgang Otorhinolaryngology Hospital, Shenzhen 518172, China
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Mao C, He H, Chen C, Gu X. Synergistic effect of collagen cross-linking and remineralization for improving resin-dentin bond durability. Eur J Oral Sci 2023; 131:e12928. [PMID: 36931874 DOI: 10.1111/eos.12928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 02/17/2023] [Indexed: 03/19/2023]
Abstract
In this study, the synergistic effect of glutaraldehyde-cross-linking and remineralization on the strength and durability of resin-dentin bonds was investigated. Dentin surfaces were etched with 35% phosphoric acid. The control specimens were bonded with Adper Single Bond 2 using wet bonding without pretreatment. The experimental specimens were pretreated with 5% (v/v) glutaraldehyde solution for 3 min and placed in a remineralizing solution for 0, 12, and 24 h, followed by dry bonding. After performing composite build-ups on the specimens, they were longitudinally sectioned, immediately, and after aging for 3 h with sodium hypochlorite (NaOCl), to evaluate microtensile bond strength (µTBS). The cross-linked specimens exhibited µTBS values comparable with those of the control group, but the µTBS decreased significantly after NaOCl aging. The cross-linked dentin remineralized for 24 h exhibited an increase in µTBS. After aging in NaOCl, the µTBS of the specimens remineralized for 24 h did not decrease and was significantly higher than for the other experimental groups. Cross-linking with dry bonding maintained µTBS in specimens before aging in NaOCl, but the bonding durability was compromised. Remineralization of cross-linked dentin for 24 h followed by dry bonding increased the immediate µTBS and improved bond durability. Therefore, combining cross-linking with remineralization of collagen fibrils progressively increased resistance to degradation, improving bond durability.
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Affiliation(s)
- Caiyun Mao
- Department of Stomatology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, P.R. China
| | - Huihui He
- Zhejiang University School of Stomatology, Hangzhou, Zhejiang Province, P.R. China
| | - Chaoqun Chen
- Department of Stomatology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, P.R. China
| | - Xinhua Gu
- Department of Stomatology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, P.R. China
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Enrique Cuevas-Suárez C, Aldrighi Münchow E, Gonçalves Schwarzbold C, Kuhn Rutz J, Fernandes da Silva A, Piva E. Effect of naturally derived antioxidants as polymerization inhibitors on experimental adhesive resins. J Photochem Photobiol A Chem 2023. [DOI: 10.1016/j.jphotochem.2022.114368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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YEŞİL ACAR Z, TUNÇ KOÇYİĞİT M, ASİLTÜRK M. Investigation of the effect of matrix-interface formed with silane-based coupling agents on physico-chemical behavior and flow distance of dental composites. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
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Somrit P, Tantilertanant Y, Srisawasdi S. Primer application technique and remaining dentin thickness affected microtensile bond strength of contemporary dentin adhesives under simulated pulp pressure. Clin Oral Investig 2023; 27:139-149. [PMID: 36109375 DOI: 10.1007/s00784-022-04699-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 08/26/2022] [Indexed: 01/28/2023]
Abstract
OBJECTIVES To evaluate the effect of application techniques, type of adhesives and remaining dentin thicknesses on microtensile bond strength (µTBS) of 3 adhesive systems. MATERIALS AND METHODS 112 flat occlusal dentinal surfaces of third molar were randomly allocated into 16 groups based on 2 remaining dentin thicknesses (RDT), 2 application techniques, and 3 adhesive systems (Optibond FL, OFL; Clearfil SE Bond, CSE; and Single Bond Universal, SB); SB was applied in either etch-and-rinse (ER) or self-etch (SE) mode. Simulated pulpal pressure was performed during restorative procedure and water storage. The stick-shaped specimens from each tooth underwent µTBS testing. The data were evaluated using a paired t test and ANOVA followed by a post hoc test. The fractured specimens were evaluated for mode of failure using a stereomicroscope. RESULTS The mean µTBS values were significantly affected by RDT, application technique, and types of adhesives. Neither RDT nor application technique affected µTBS of SB in ER mode, whereas application technique affected both conventional and universal self-etch adhesives. RDT also influenced µTBS of OFL. CONCLUSIONS RDT and application technique differently affected the µTBS of dentin bonding which was product-related. Etch-and-rinse systems had higher bond strength to superficial than to deep dentin, whereas self-etch systems were more sensitive to both RDT and application technique. CLINICAL RELEVANCE The universal adhesive is less sensitive to intrinsic wetness and can be used according to manufacturer's instructions.
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Affiliation(s)
- Paphawee Somrit
- Department of Operative Dentistry, Faculty of Dentistry, Chulalongkorn University, Henri-Dunant Road, Pathumwan, Bangkok, 10330, Thailand.
| | - Yanee Tantilertanant
- Department of Operative Dentistry, Faculty of Dentistry, Chulalongkorn University, Henri-Dunant Road, Pathumwan, Bangkok, 10330, Thailand
| | - Sirivimol Srisawasdi
- Department of Operative Dentistry, Faculty of Dentistry, Chulalongkorn University, Henri-Dunant Road, Pathumwan, Bangkok, 10330, Thailand
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Stape THS, Viita-aho T, Sezinando A, Seseogullari-Dirihan R, Eleftheriadi E, Mutluay M, Tezvergil-Mutluay A. To etch or not to etch, Part II: On the hydrophobic-rich content and fatigue strength of universal adhesives. Dent Mater 2022; 38:1419-1431. [DOI: 10.1016/j.dental.2022.06.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 06/09/2022] [Accepted: 06/22/2022] [Indexed: 11/03/2022]
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How Water Content Can Influence the Chemomechanical Properties and Physical Degradation under Aging of Experimental Adhesives. Int J Dent 2022; 2022:5771341. [PMID: 35265134 PMCID: PMC8898883 DOI: 10.1155/2022/5771341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/18/2022] [Accepted: 02/02/2022] [Indexed: 12/04/2022] Open
Abstract
Objective To evaluate the physicochemical (sorption (SOR), solubility (SOL), and degree of conversion (DC)) and mechanical (flexural strength (FS), modulus of elasticity (ME), and compressive strength (CS)) properties of adhesives with different water contents (D2O). Materials and Methods An adhesive was formulated: 55 wt% BisGMA, 45 wt% HEMA, 0.5 wt% camphorquinone, 0.5 wt% EDMAB, and 1.0 wt% DPIHP. D2O was added into the adhesives (0 wt%, 10 wt%, and 16 wt%). DC was monitored through the FTIR. FS, ME, CS, SOR, and SOL were tested. The adhesive samples were aged in deionized water, ethanol, and acetone. Data were submitted to ANOVA and Tukey's tests (5%). Results For DC, the 0 wt% group showed a significant reduction (68.09 ± 0.14A) compared with the 10 wt% (87.07 ± 0.81B) and 16 wt% groups (89.87 ± 0.24B); 10 wt% showed the highest FS (MPa) mean values (141.6 ± 6.71B) compared with the 0 wt% (109.4 ± 20.5A) and 16 wt% (107.8 ± 15.8A). For the CS (MPa) and ME (GPa), the 16 wt% showed the lowest mean values (98.8 ± 18.0B and 2.2 ± 0.3B, respectively) compared with the 10 wt% and 0 wt%. For the SOR, 16 wt% of water showed the highest mean values and the ethanol showed the lowest mean values of SOL regardless of water content. Conclusion The amount of water content and the types of aging solvents significantly affect the adhesive properties.
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Citta M, Anovazzi G, Basso FG, Scheffel D, Zhou J, Pashley DH, Souza Costa CA, Hebling J. Mechanical Stability and Proteolytic Activity of Resin-dentin Bonds Using the Cross-linked Dry Bonding Technique. Oper Dent 2021; 46:E251-E263. [PMID: 34919726 DOI: 10.2341/20-016-l] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/19/2021] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To evaluate the mechanical stability and the proteolytic activity of bonds created by a two-step, etch-and-rinse adhesive applied to cross-linked and air-dried etched dentin. METHODS Flat dentin surfaces were produced in 64 extracted sound human molars. The dentin was etched with 35% phosphoric acid for 15 seconds, and then the teeth were divided into groups according to the cross-linking solution applied on the etched dentin. Group 1: 5% grape seed extract (GSE), Group 2: 5% glutaraldehyde, Group 3: Gluma Desensitizer, or Group 4: deionized water (control). Solutions were applied for 60 seconds, followed by rinse and blot drying. Then, the teeth were separated into two subgroups where the etched dentin was kept moist or air-dried. The adhesive was applied followed by a composite resin buildup. After 24 hours, the teeth were cut into beams (0.81 mm2) that were tested for microtensile strength immediately or after 12 months of aging in a 37°C saliva-like buffer. Additional teeth (n=32) were bonded as described and cut into 0.5-mm-thick slabs. The slabs were prepared for nanoleakage (scanning electron microscopy) and in situ zymography (EnzChek Protease Assay Kit). Bond strength data were submitted to ANOVA and Tukey tests (α=0.05). RESULTS Significant reduction in immediate bond strength (ca 65%) and increase in proteolytic activity was seen when the etched dentin was air dried without previous cross-linking biomodification. Conversely, bond strengths did not differ from those produced on wet dentin when collagen was cross-linked before air drying, irrespective of the solution applied. For both moist and air-dried etched dentin, collagen cross-linking resulted in mechanically stable bonds and reduced proteolytic activity after 12 months of storage. CONCLUSION Bonds produced by the application of a two-step, etch-and-rinse adhesive to cross-linked, air-dried, etched dentin were mechanically stable and revealed reduced proteolytic activity after 1 year of aging.
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Affiliation(s)
- M Citta
- Mariana Citta, DDS, MSc, Department of Oral Rehabilitation, Sao Paulo State University (UNESP), School of Dentistry, SP, Brazil
| | - G Anovazzi
- Giovana Anovazzi, DDS, MSc, PhD, Department of Orthodontics and Pediatric Dentistry, Sao Paulo State University (UNESP), School of Dentistry, SP, Brazil
| | - F G Basso
- Fernanda Gonçalves Basso, DDS, MSc, PhD, Department of Oral Rehabilitation, Sao Paulo State University (UNESP), School of Dentistry, SP, Brazil
| | - Dls Scheffel
- Débora Lopes Salles Scheffel, DDS, MSc, PhD, Department of Dentistry, State University of Maringá, School of Dentistry, PR, Brazil
| | - J Zhou
- Jianfeng Zhou, DMD, PhD, Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing, PR China
| | - D H Pashley
- David Henry Pashley, DMD, PhD, Department of Oral Biology, The Dental College of Georgia, Augusta University, Augusta, GA, United States
| | - C A Souza Costa
- Carlos Alberto de Souza Costa, DDS, MSc, PhD, Department of Physiology and Pathology, Sao Paulo State University (UNESP), School of Dentistry, SP, Brazil
| | - J Hebling
- *Josimeri Hebling, DDS, MSc, PhD, Department of Orthodontics and Pediatric Dentistry, Sao Paulo State University (UNESP), School of Dentistry, SP, Brazil
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Fugolin APP, Navarro O, Logan MG, Huynh V, França CM, Ferracane JL, Pfeifer CS. Synthesis of di- and triacrylamides with tertiary amine cores and their evaluation as monomers in dental adhesive interfaces. Acta Biomater 2020; 115:148-159. [PMID: 32853802 DOI: 10.1016/j.actbio.2020.08.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/24/2020] [Accepted: 08/14/2020] [Indexed: 01/13/2023]
Abstract
PURPOSE/AIM In an attempt to increase the service life of dental adhesive interfaces, more hydrolytically and enzymatically-stable methacrylate alternatives, such as methacrylamides, have been proposed. The aim of this study was to investigate polymerization behavior, as well as mechanical and biological properties of experimental adhesives containing multi-functional acrylamides. MATERIALS AND METHODS Multi-functional acrylamides (N,N-Bis[(3-methylaminoacryl)propyl]methylamine - BMAAPMA, Tris[(2-methylaminoacryl)ethyl]amine - TMAAEA, N,N'-bis(acrylamido) 1,4-diazepane - BAADA, N,N-Diethyl-1,3-bis(acrylamido)propane - DEBAAP) or HEMA (2-Hydroxyethyl methacrylate - control) were added at 40 wt% to UDMA. 0.2 wt% DMPA and 0.4 wt% DPI-PF6 were used as initiators. Polymerization kinetics was followed in real-time in near-IR during photoactivation (320-500 nm, at 630 mW/cm2). Water sorption/solubility and flexural strength/modulus were measured according to ISO 4049. 1H NMR was used to assess monomer degradation kinetics. MTT assay was used to assess cytotoxicity against OD-21 and DPSC cells. Biofilm formation and adhesion were assessed by Luciferase Assay and Impingement technique, respectively. Solvated adhesives (40 vol% ethanol) were used to test interfacial adhesion strength. The results were analyzed by ANOVA/Tukey's test (α = 0.05). RESULTS In general, the pure methacrylate mixture had higher rate of polymerization (Rpmax), degree of conversion (DC) at Rpmax, and final DC than the acrylamides. Flexural properties after water storage decreased between 11 and 65%, more markedly for acrylamides. Interfacial bond strength was greater and more stable long-term for the newly synthesized acrylamide formulations (less than 4% reduction at 6 months) compared to the methacrylate experimental control (42% reduction at 6 months). HEMA degraded by almost 90%, while the acrylamides showed no degradation in acidic conditions. Cytotoxicity and biofilm formation, in general, were similar for all groups. CONCLUSIONS Despite demonstrating high water sorption, the acrylamide-containing materials had similar mechanical and biological properties and enhanced interfacial bond strength stability compared to the methacrylate control.
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Affiliation(s)
- A P P Fugolin
- Biomaterials and Biomechanics, Department of Restorative Dentistry, Oregon Health & Science University, Portland OR 97239, USA
| | - Oscar Navarro
- Biomaterials and Biomechanics, Department of Restorative Dentistry, Oregon Health & Science University, Portland OR 97239, USA
| | - Matthew G Logan
- Biomaterials and Biomechanics, Department of Restorative Dentistry, Oregon Health & Science University, Portland OR 97239, USA
| | - Vincent Huynh
- Biomaterials and Biomechanics, Department of Restorative Dentistry, Oregon Health & Science University, Portland OR 97239, USA
| | - Cristiane M França
- Biomaterials and Biomechanics, Department of Restorative Dentistry, Oregon Health & Science University, Portland OR 97239, USA
| | - Jack L Ferracane
- Biomaterials and Biomechanics, Department of Restorative Dentistry, Oregon Health & Science University, Portland OR 97239, USA
| | - Carmem S Pfeifer
- Biomaterials and Biomechanics, Department of Restorative Dentistry, Oregon Health & Science University, Portland OR 97239, USA.
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Polyphenol-enriched extract of Arrabidaea chica used as a dentin pretreatment or incorporated into a total-etching adhesive system: Effects on bonding stability and physical characterization. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2020; 116:111235. [PMID: 32806286 DOI: 10.1016/j.msec.2020.111235] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 05/15/2020] [Accepted: 06/21/2020] [Indexed: 11/22/2022]
Abstract
The aim of this paper was to evaluate the physical properties and the long-term bond strength of a 2.5% polyphenol-enriched extract of Arrabidaea chica (AC) incorporated into both the phosphoric acid and the primer of a three-step total-etch adhesive, or into an aqueous solution as a dentin pretreatment. Fifty dentin surfaces received the treatments (n = 10): CON (control) - application of the three-step adhesive system (Adper Scotchbond Multipurpose, 3M ESPE); WAT - distilled water used as a pretreatment after dentin etching and before application of the adhesive system; ACPA - AC incorporated into the phosphoric acid; ACW - dentin pre-treatment with AC incorporated into an aqueous solution after etching; ACP - AC incorporated into the primer. Microtensile bond strength tests were performed after 24 h, 6 and 12 months of storage. Slices from the resin-dentin interface were obtained for scanning electron microscopy analysis of the hybrid layer. Degree of conversion of AC incorporated into the primer was evaluated. The particle size, polydispersity index and zeta potential of all the solutions prepared by incorporating AC (phosphoric acid, primer and distilled water) were measured by dynamic light scattering, which brought about changes after incorporation. Degree of conversion of the primer was not affected after incorporating AC. ACP showed lower microtensile bond strength values than the other groups. Bond strength decreased after 6 months of storage, stabilizing at the 12-month evaluation. Therefore, use of AC incorporated into the primer led to lower bond strength values, since AC modified the physical properties (particle size, polydispersity index and zeta potential) of the primer, but did not change the degree of conversion. Application of AC as a dentin pretreatment did not affect bond strength or the micromorphological characteristics of the hybrid layer.
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Abedin F, Ye Q, Spencer P. Hydrophilic dyes as photosensitizers for photopolymerization of dental adhesives. J Dent 2020; 99:103405. [PMID: 32522687 DOI: 10.1016/j.jdent.2020.103405] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 05/30/2020] [Accepted: 06/03/2020] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVES This study explored hydrophilic dyes as photosensitizers for application in dental adhesives. The goal was to identify dyes that enhance the degree of conversion (DC) of the hydrophilic-rich phase without impairing polymerization of the hydrophobic-rich phase. METHODS Properties that were investigated included the molar extinction coefficient at 480 nm, relative normalized photon absorption efficiency (PAE), rate of polymerization and degree of conversion (DC). The following hydrophilic dyes: Bromophenol blue sodium salt, Rosebengal sodium salt, Erythrosin B, New Fuchsin and Victoria blue B were identified as suitable photosensitizers. RESULTS In this study it was observed that dyes such as Bromophenol blue sodium salt, New Fuchsin, Victoria blue B and Rosebengal sodium salt were suitable candidates for dental adhesive photopolymerization, leading to substantial degree of conversion to both the hydrophilic-rich phase and the hydrophobic-rich phase. CONCLUSIONS In addition to the ability of the photosensitizer to absorb light in the visible range and transition to an excited state as a result of the absorbed energy, other factors such as the efficiency of the photosensitizer/light curing unit (LCU) combination, stability/efficiency of the excited state of the photosensitizer and/or initiating reactive species play an important role in the photopolymerization of the dental adhesive.
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Affiliation(s)
- Farhana Abedin
- Department of Electromechanical Engineering Technology, California State Polytechnic University, 3801 W Temple Ave, Pomona, CA, 91768, United States.
| | - Qiang Ye
- Institute of Bioengineering Research Laboratories, The University of Kansas, 1530 W 15thStreet, Lawrence, KS, 66045, United States.
| | - Paulette Spencer
- Institute of Bioengineering Research Laboratories, The University of Kansas, 1530 W 15thStreet, Lawrence, KS, 66045, United States; Department of Mechanical Engineering, The University of Kansas, 1530 W 15thStreet, Lawrence, KS, 66045, United States.
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Geng Vivanco R, Cardoso RS, Sousa ABS, Chinelatti MA, Vincenti SADF, Tonani-Torrieri R, Pires-de-Souza FDCP. Effect of thermo-mechanical cycling and chlorhexidine on the bond strength of universal adhesive system to dentin. Heliyon 2020; 6:e03871. [PMID: 32373750 PMCID: PMC7191587 DOI: 10.1016/j.heliyon.2020.e03871] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 04/02/2020] [Accepted: 04/23/2020] [Indexed: 11/30/2022] Open
Abstract
OBJECTIVES This study evaluated the influence of thermo-mechanical cycling (TMC) on the bond strength (BS) of a universal adhesive system (UAS - Adper Single Bond Universal, 3M ESPE) to dentin treated or not with 0.2% chlorhexidine (CHX). METHODS Eighty human molars were flattened until reach the dentin and separated into 4 groups according to the bonding protocol: ENR Group: 37% phosphoric acid + 3-step etch-and-rinse adhesive system (ENR); UAS Group: UAS in self-etch mode; ENR + CHX Group: 37% phosphoric acid + CHX + ENR; UAS + CHX Group: CHX + UAS in self-etch mode. After treatments, teeth were restored (Filtek Z350, 3M ESPE). Samples (n = 10) were submitted to aging process: stored in distilled water at 37°C/30 days or TMC (ERIOS - 98N/1.6Hz + thermal cycling 5/37/55 °C - 1,200,000 cycles). Specimens were sectioned into sticks (1.0 mm2) and submitted to the microtensile test (Mechanical Test Machine - 0.5 mm/min). Fracture patterns and hybrid layer integrity were analyzed under Stereomicroscope and Scanning Electron Microscopy (SEM). RESULTS The BS results (3-way ANOVA, Bonferroni's test, α = 5%) showed that groups treated with CHX presented higher BS values than control groups; significant in all cases (p < .05), except for ENR submitted to TMC (p > .05). When CHX was applied and samples were cycled, UAS revealed higher BS (p < .05) than ENR. After TMC, cohesive fractures increased for UAS, regardless of CHX application. SEM analysis demonstrated different hybridization patterns for the adhesive systems tested. CONCLUSION The performance of the universal adhesive system used in self-etch mode was better than that of the 3-step etch-and-rinse adhesive system. CLINICAL SIGNIFICANCE Universal adhesive systems have been developed in order to simplify the dentin hybridization protocol. It is important to determine the longevity of the adhesive interface using these bonding materials after chewing.
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Affiliation(s)
- Rocio Geng Vivanco
- Department of Dental Materials and Prosthodontics, Ribeirão Preto School of Dentistry, University of São Paulo, Av do Café s/n, 14040-904, Ribeirão Preto, SP, Brazil
| | - Renata Silva Cardoso
- Department of Dental Materials and Prosthodontics, Ribeirão Preto School of Dentistry, University of São Paulo, Av do Café s/n, 14040-904, Ribeirão Preto, SP, Brazil
| | - Ana Beatriz Silva Sousa
- School of Dentistry, University of Ribeirão Preto, Av Costábile Romano, 2.201, 14096-900, Ribeirão Preto, SP, Brazil
| | - Michelle Alexandra Chinelatti
- Department of Dental Materials and Prosthodontics, Ribeirão Preto School of Dentistry, University of São Paulo, Av do Café s/n, 14040-904, Ribeirão Preto, SP, Brazil
| | - Sergio Augusto de Freitas Vincenti
- Department of Dental Materials and Prosthodontics, Ribeirão Preto School of Dentistry, University of São Paulo, Av do Café s/n, 14040-904, Ribeirão Preto, SP, Brazil
| | - Rafaella Tonani-Torrieri
- Department of Dental Materials and Prosthodontics, Ribeirão Preto School of Dentistry, University of São Paulo, Av do Café s/n, 14040-904, Ribeirão Preto, SP, Brazil
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Ruivo MA, Pacheco RR, Sebold M, Giannini M. Surface roughness and filler particles characterization of resin-based composites. Microsc Res Tech 2019; 82:1756-1767. [PMID: 31313442 DOI: 10.1002/jemt.23342] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 05/22/2019] [Accepted: 06/27/2019] [Indexed: 11/11/2022]
Abstract
The purpose of this study was to evaluate the surface roughness (Ra), and the morphology and composition of filler particles of different composites submitted to toothbrushing and water storage. Disc-shaped specimens (15 mm × 2 mm) were made from five composites: two conventional (Z100™, and Filtek™ Supreme Ultra Universal, 3M), one "quick-cure" (Estelite ∑ Quick, Tokuyama), one fluoride-releasing (Beautiful II, Shofu), and one self-adhering (Vertise Flow, Kerr) composite. Samples were finished/polished using aluminum oxide discs (Sof-Lex, 3M), and their surfaces were analyzed by profilometry (n = 5) and scanning electron microscopy (SEM; n = 3) at 1 week and after 30,000 toothbrushing cycles and 6-month water storage. Ra data were analyzed by two-way analysis of variance and Tukey's test (α = 0.05). Filler particles morphology and composition were analyzed by SEM and X-ray dispersive energy spectroscopy, respectively. Finishing/polishing resulted in similar Ra for all the composites, while toothbrushing and water storage increased the Ra of all the tested materials, also changing their surface morphology. Beautifil II and Vertise Flow presented the highest Ra after toothbrushing and water storage. Filler particles were mainly composed of silicon, zirconium, aluminum, barium, and ytterbium. Size and morphology of fillers, and composition of the tested composites influenced their Ra when samples were submitted to toothbrushing and water storage.
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Affiliation(s)
- Melissa A Ruivo
- Department of Restorative Dentistry, Dental Materials Division, University of Campinas, Piracicaba Dental School, Piracicaba, SP, Brazil
| | - Rafael R Pacheco
- Department of Restorative Dentistry, Dental Materials Division, University of Campinas, Piracicaba Dental School, Piracicaba, SP, Brazil
| | - Maicon Sebold
- Department of Restorative Dentistry, Operative Dentistry Division, University of Campinas, Piracicaba Dental School, Piracicaba, SP, Brazil
| | - Marcelo Giannini
- Department of Restorative Dentistry, Operative Dentistry Division, University of Campinas, Piracicaba Dental School, Piracicaba, SP, Brazil
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Parthasarathy R, Misra A, Song L, Ye Q, Spencer P. Structure-property relationships for wet dentin adhesive polymers. Biointerphases 2018; 13:061004. [PMID: 30558430 PMCID: PMC6296910 DOI: 10.1116/1.5058072] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 11/27/2018] [Accepted: 11/28/2018] [Indexed: 12/23/2022] Open
Abstract
Dentin adhesive systems for composite tooth restorations are composed of hydrophilic/hydrophobic monomers, solvents, and photoinitiators. The adhesives undergo phase separation and concomitant compositional change during their application in the wet oral environment; phase separation compromises the quality of the hybrid layer in the adhesive/dentin interface. In this work, the adhesive composition in the hybrid layer can be represented using the phase boundaries of a ternary phase diagram for the hydrophobic monomer/hydrophilic monomer/water system. The polymer phases, previously unaccounted for, play an important role in determining the mechanical behavior of the bulk adhesive, and the chemomechanical properties of the phases are intimately related to the effects produced by differences in the hydrophobic-hydrophilic composition. As the composition of the polymer phases varies from hydrophobic-rich to hydrophilic-rich, the amount of the adsorbed water and the nature of polymer-water interaction vary nonlinearly and strongly correlate with the change in elastic moduli under wet conditions. The failure strain, loss modulus, and glass transition temperature vary nonmonotonically with composition and are explained based upon primary and secondary transitions observed in dynamic mechanical testing. Due to the variability in composition, the assignment of mechanical properties and the choice of suitable constitutive models for polymer phases in the hybrid layer are not straightforward. This work investigates the relationship between composition and chemomechanical properties of the polymer phases formed on the water-adhesive phase boundary using quasistatic and dynamic mechanical testing, mass transfer experiments, and vibrational spectroscopy.
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Affiliation(s)
- Ranganathan Parthasarathy
- Department of Civil and Architectural Engineering, Tennessee State University, 3500 John A Merritt Blvd, Nashville, Tennessee 37209
| | - Anil Misra
- Department of Civil and Environmental Engineering, Institute for Bioengineering Research, University of Kansas, 5104B Learned Hall, 1530 W 15th Street, Lawrence, Kansas 66045
| | - Linyong Song
- Institute for Bioengineering Research, University of Kansas, 5104A Learned Hall, 1530 W 15th Street, Lawrence, Kansas 66045
| | - Qiang Ye
- Institute for Bioengineering Research, University of Kansas, 5101E Learned Hall, 1530 W 15th Street, Lawrence, Kansas 66045
| | - Paulette Spencer
- Department of Mechanical Engineering, Institute for Bioengineering Research, University of Kansas, 3111 Learned Hall, 1530 W 15th Street, Lawrence, Kansas 66045
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Azad E, Atai M, Zandi M, Shokrollahi P, Solhi L. Structure–properties relationships in dental adhesives: Effect of initiator, matrix monomer structure, and nano-filler incorporation. Dent Mater 2018; 34:1263-1270. [DOI: 10.1016/j.dental.2018.05.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 04/24/2018] [Accepted: 05/09/2018] [Indexed: 11/16/2022]
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Ye Q, Abedin F, Parthasarathy R, Spencer P. Photoinitiators in Dentistry: Challenges and Advances. PHOTOPOLYMERISATION INITIATING SYSTEMS 2018. [DOI: 10.1039/9781788013307-00297] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Photopolymerization is used in a wide range of clinical applications in dentistry and the demand for dental materials that can restore form, function and esthetics is increasing rapidly. Simultaneous with this demand is the growing need for photoinitiators that provide effective and efficient in situ polymerization of dental materials using visible light irradiation. This chapter reviews the fundamentals of Type I and II photoinitiators. The advantages and disadvantages of these photoinitiators will be considered with a particular focus on parameters that affect the polymerization process in the oral cavity. The chapter examines recent developments in photoinitiators and opportunities for future research in the design and development of photoinitiators for dental applications. Future research directions that employ computational models in conjunction with iterative synthesis and experimental methods will also be explored in this chapter.
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Affiliation(s)
- Qiang Ye
- Institute for Bioengineering Research, School of Engineering, University of Kansas 1530 W. 15th St Lawrence KS 66045 USA
| | - Farhana Abedin
- Electromechanical Engineering Technology program, College of Engineering, California State Polytechnic University Pomona 3801 W. Temple Ave Pomona CA 91768 USA
| | - Ranganathan Parthasarathy
- Nanomaterials Research Lab, Tennessee State University 3500 John A Merritt Blvd Nashville TN 37209 USA
| | - Paulette Spencer
- Institute for Bioengineering Research, School of Engineering, University of Kansas 1530 W. 15th St Lawrence KS 66045 USA
- Department of Mechanical Engineering, University of Kansas 1530 W. 15th St Lawrence KS 66045 USA
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Abstract
From the conception of resin-enamel adhesion to today's contemporary dental adhesive systems, clinicians are no longer afraid of exploring the many advantages brought by adhesive restorative concepts. To maximize the performance of adhesive-based restorative procedures, practitioners must be familiar with the mechanism of adhesion, clinical indications, proper handling, the inherent limitations of the materials and the biological challenges. This review provides an overview of the current status of restorative dental adhesives, their mechanism of adhesion, mechanisms of degradation of dental adhesive interfaces, how to maximize performance, and future trends in adhesive dentistry.
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Pucci CR, Gu LS, Zeng C, Gou YP, Tay FR, Niu LN. Susceptibility of contemporary single-bottle self-etch dentine adhesives to intrinsic water permeation. J Dent 2017; 66:52-61. [PMID: 28844892 DOI: 10.1016/j.jdent.2017.08.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 08/10/2017] [Accepted: 08/19/2017] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVES To evaluate the effect of intrinsic water permeation on the microtensile bond strengths of different adhesive systems to dentine and the quality of resin-dentine interfaces. METHODS Ninety-six non-carious human third molars were divided into 4 groups: Clearfil S3 Bond Plus (CSBP; Kuraray); Clearfil S3 Bond (C3S; Kuraray); iBond Self-Etch (IB; Heraeus-Kulzer) and Prime&Bond NT (PB, control etch-and-rinse adhesive, Dentply-Sirona). For each adhesive, specimens from one subgroup (N=10) were bonded using zero pulpal pressure, while specimens from the other subgroup (N=10) were bonded using 15cm water pressure (PP). Each bonded tooth was sectioned into 1×1mm sticks and stressed to failure. Data were analysed using two-way ANOVA and Holm-Sidak pairwise comparisons to examine the effects of "adhesive", "pulpal pressure" and their interaction on bond strength (α=0.05). Representative fractured sticks were examined by SEM. The remaining tooth slabs in each subgroup were used for TEM and CLSM. RESULTS Microtensile bond strengths (mean±SD; in MPa) were: 33.4±6.9 (CSBP), 33.2±4.7 (CSBP-PP), 35.0±8.6 (C3S), 25.5±7.3 (C3S-PP), 18.4±4.0 (IB), 16.5±6.9 (IB-PP), 28.2±5.5 (PB), 20.5±7.2 (PB-PP). "Adhesive-type" (P<0.001), "pulpal-pressure" (P<0.001) and their interactions (P<0.001) significantly affected bond strength results. No difference between no-PP and PP subgroups was found for CSBP and IB (P>0.05). Water droplets were identified along the resin-dentine interface for IB, IB-PP and C3S-PP. CONCLUSION IB exhibits water sensitivity when bonding is performed with/without pulpal pressure. C3S exhibits water sensitivity when bonding is performed with pulpal pressure. CSBP does not exhibit water sensitivity when bonding is performed with/without pulpal pressure. CLINICAL SIGNIFICANCE Intrinsic water permeation during bonding procedures significantly affects bond strength results and the resin-dentine interface of contemporary single-bottle self-etch dentine adhesive systems.
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Affiliation(s)
- Cesar R Pucci
- Department of Restorative Dentistry, Institute of Science and Technology, São Paulo State University UNESP, São Jose dos Campos, São Paulo, Brazil
| | - Li-Sha Gu
- Department of Operative Dentistry and Endodontics, Guanghua School of Stomatology & Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Chang Zeng
- Department of Stomatology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ya-Ping Gou
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Franklin R Tay
- Department of Endodontics, The Dental College of Georgia, Augusta University, Augusta, GA, USA
| | - Li-Na Niu
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, China.
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Extrafibrillar collagen demineralization-based chelate-and-rinse technique bridges the gap between wet and dry dentin bonding. Acta Biomater 2017; 57:435-448. [PMID: 28499631 DOI: 10.1016/j.actbio.2017.05.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/05/2017] [Accepted: 05/08/2017] [Indexed: 11/20/2022]
Abstract
Limitations associated with wet-bonding led to the recent development of a selective demineralization strategy in which dentin was etched with a reduced concentration of phosphoric acid to create exclusive extrafibrillar demineralization of the collagen matrix. However, the use of acidic conditioners removes calcium via diffusion of very small hydronium ions into the intrafibrillar collagen water compartments. This defeats the purpose of limiting the conditioner to the extrafibrillar space to create a collagen matrix containing only intrafibrillar minerals to prevent collapse of the collagen matrix. The present work examined the use of polymeric chelators (the sodium salt of polyacrylic acid) of different molecular weights to selectively demineralize extrafibrillar dentin. These polymeric chelators exhibit different affinities for calcium ions (isothermal titration calorimetry), penetrated intrafibrillar dentin collagen to different extents based on their molecular sizes (modified size-exclusion chromatography), and preserve the dynamic mechanical properties of mineralized dentin more favorably compared with completely demineralized phosphoric acid-etched dentin (nanoscopical dynamic mechanical analysis). Scanning and transmission electron microscopy provided evidence for retention of intrafibrillar minerals in dentin surfaces conditioned with polymeric chelators. Microtensile bond strengths to wet-bonded and dry-bonded dentin conditioned with these polymeric chelators showed that the use of sodium salts of polyacrylic acid for chelating dentin prior to bonding did not result in significant decline in resin-dentin bond strength. Taken together, the findings led to the conclusion that a chelate-and-rinse conditioning technique based on extrafibrillar collagen demineralization bridges the gap between wet and dry dentin bonding. STATEMENT OF SIGNIFICANCE The chelate-and-rinse dental adhesive bonding concept differentiates from previous research in that it is based on the size-exclusion characteristics of fibrillar collagen; molecules larger than 40kDa are prevented from accessing the intrafibrillar water compartments of the collagen fibrils. Using this chelate-and-rinse extrafibrillar calcium chelation concept, collagen fibrils with retained intrafibrillar minerals will not collapse upon air-drying. This enables adhesive infiltration into the mineral-depleted extrafibrillar spaces without relying on wet-bonding. By bridging the gap between wet and dry dentine bonding, the chelate-and-rinse concept introduces additional insight to the field by preventing exposure of endogenous proteases via preservation of the intrafibrillar minerals within a collagen matrix. If successfully validated, this should help prevent degradation of resin-dentine bonds by collagenolytic enzymes.
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Bürgin S, Rohr N, Fischer J. Assessing degradation of composite resin cements during artificial aging by Martens hardness. Head Face Med 2017; 13:9. [PMID: 28526054 PMCID: PMC5437403 DOI: 10.1186/s13005-017-0142-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 05/11/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Aim of the study was to verify the efficiency of Martens hardness measurements in detecting the degradation of composite resin cements during artificial aging. METHODS Four cements were used: Variolink II (VL2), RelyX Unicem 2 Automix (RUN), PermaFlo DC (PDC), and DuoCem (DCM). Specimens for Martens hardness measurements were light-cured and stored in water at 37 °C for 1 day to allow complete polymerization (baseline). Subsequently the specimens were artificially aged by water storage at 37 °C or thermal cycling (n = 6). Hardness was measured at baseline as well as after 1, 4, 9 and 16 days of aging. Specimens for indirect tensile strength measurements were produced in a similar manner. Indirect tensile strength was measured at baseline and after 16 days of aging (n = 10). The results were statistically analyzed using one-way ANOVA (α = 0.05). RESULTS After water storage for 16 days hardness was significantly reduced for VL2, RUN and DCM while hardness of PDC as well as indirect tensile strength of all cements were not significantly affected. Thermal cycling significantly reduced both, hardness and indirect tensile strength for all cements. No general correlation was found between Martens hardness and indirect tensile strength. However, when each material was analyzed separately, relative change of hardness and of indirect tensile strength revealed a strong linear correlation. CONCLUSIONS Martens hardness is a sensible test method to assess aging of resin composite cements during thermal cycling that is easy to perform.
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Affiliation(s)
- Stefan Bürgin
- Division of Dental Materials and Engineering, Department of Reconstructive Dentistry and Temporomandibular Disorders, University Center for Dental Medicine Basel, University of Basel, Hebelstrasse 3, 4056, Basel, Switzerland
| | - Nadja Rohr
- Division of Dental Materials and Engineering, Department of Reconstructive Dentistry and Temporomandibular Disorders, University Center for Dental Medicine Basel, University of Basel, Hebelstrasse 3, 4056, Basel, Switzerland.
| | - Jens Fischer
- Division of Dental Materials and Engineering, Department of Reconstructive Dentistry and Temporomandibular Disorders, University Center for Dental Medicine Basel, University of Basel, Hebelstrasse 3, 4056, Basel, Switzerland
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Huang XQ, Pucci CR, Luo T, Breschi L, Pashley DH, Niu LN, Tay FR. No-waiting dentine self-etch concept-Merit or hype. J Dent 2017; 62:54-63. [PMID: 28506642 DOI: 10.1016/j.jdent.2017.05.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 05/10/2017] [Accepted: 05/11/2017] [Indexed: 10/19/2022] Open
Abstract
OBJECTIVE A recently-launched universal adhesive, G-Premio Bond, provides clinicians with the alternative to use the self-etch technique for bonding to dentine without waiting for the adhesive to interact with the bonding substrate (no-waiting self-etch; Japanese brochure), or after leaving the adhesive undisturbed for 10s (10-s self-etch; international brochure). The present study was performed to examine in vitro performance of this new universal adhesive bonded to human coronal dentine using the two alternative self-etch modes. METHODS One hundred and ten specimens were bonded using two self-etch application modes and examined with or without thermomechanical cycling (10,000 thermal cycles and 240,000 mechanical cycles) to simulate one year of intraoral functioning. The bonded specimens were sectioned for microtensile bond testing, ultrastructural and nanoleakage examination using transmission electron microscopy. Changes in the composition of mineralised dentine after adhesive application were examined using Fourier transform infrared spectroscopy. RESULTS Both reduced application time and thermomechanical cycling resulted in significantly lower bond strengths, thinner hybrid layers, and significantly more extensive nanoleakage after thermomechanical cycling. Using the conventional 10-s application time improved bonding performance when compared with the no-waiting self-etch technique. Nevertheless, nanoleakage was generally extensive under all testing parameters employed for examining the adhesive. CONCLUSION Although sufficient bond strength to dentine may be achieved using the present universal adhesive in the no-waiting self-etch mode that does not require clinicians to wait prior to polymerisation of the adhesive, this self-etch concept requires further technological refinement before it can be recommended as a clinical technique. CLINICAL SIGNIFICANCE Although the surge for cutting application time to increase user friendliness remains the most frequently sought conduit for advancement of dentine bonding technology, the use of the present universal adhesive in the no-waiting self-etch mode may not represent the best use of the adhesive.
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Affiliation(s)
- Xue-Qing Huang
- Department of Prosthodontics, Guanghua School and Hospital of Stomatology & Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, PR China
| | - César R Pucci
- Department of Restorative Dentistry, Institute of Science and Technology, São Paulo State University UNESP São Jose dos Campos, São Paulo, Brazil
| | - Tao Luo
- Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou, Guangdong, PR China
| | - Lorenzo Breschi
- Department of Biomedical and Neuromotor Sciences, DIBINEM, University of Bologna - Alma Mater Studiorum, Bologna, Italy
| | - David H Pashley
- College of Graduate Studies, Augusta University, Augusta, GA, USA
| | - Li-Na Niu
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, PR China.
| | - Franklin R Tay
- College of Graduate Studies, Augusta University, Augusta, GA, USA.
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Computer-aided Molecular Design of Water Compatible Visible Light Photosensitizers for Dental Adhesive. Chem Eng Sci 2016; 159:131-139. [PMID: 29176909 DOI: 10.1016/j.ces.2016.09.033] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Dental adhesive resin undergoes phase separation during its infiltration through the wet demineralized dentin and it has been observed previously that the hydrophilic-rich phase is a vulnerable region for failure due to the lack of photo-polymerization and crosslinking density. The lack of photo-polymerization is mostly due to the partitioning of photo-initiators in low concentrations within this phase. Here, a computational approach has been employed to design candidate water compatible visible light photosensitizers which could improve the photo-polymerization of the hydrophilic-rich phase. This study is an extension of our previous work. QSPRs were developed for properties related to the photo-polymerization reaction of the adhesive monomers and hydrophilicity of the photosensitizer using connectivity indices as descriptors. QSPRs and structural constraints were formulated into an optimization problem which was solved stochastically via Tabu Search. Four candidate photosensitizer molecules have been proposed here which have the iminium ion as a common feature.
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Cross-linked dry bonding: A new etch-and-rinse technique. Dent Mater 2016; 32:1124-32. [PMID: 27431091 DOI: 10.1016/j.dental.2016.06.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 03/16/2016] [Accepted: 06/22/2016] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To determine if acid-etched, cross-linked dentin can be dehydrated without lowering bond strength below that of cross-linked wet-bonded dentin in vitro. METHODS Using extracted human third molars, control acid-etched dentin was bonded with Single Bond Plus, using either the wet- or dry-bonding technique. Experimental acid-etched dentin was treated with 5mass% grape seed extract (GSE) in different solvents for 1min before undergoing wet vs dry resin-dentin bonding with Single Bond Plus. Completely demineralized dentin beams were treated with 5% GSE for 0, 1 or 10min, before measuring stiffness by 3-point flexure. Other completely demineralized beams were treated similarly and then incubated in buffer for 1 week to measure the collagen solubilization by endogenous dentin proteases. RESULTS 24h microtensile bond strengths (μTBS) in wet and dry controls were 53.5±3.6 and 9.4±1.8MPa, respectively (p<0.05). 5% GSE in water gave μTBS of 53.7±3.4 and 39.1±9.7MPa (p<0.05), respectively, while 5% GSE in ethanol gave μTBS of 51.2±2.3 and 35.3±2.0MPa (p<0.05). 5% GSE in 5% EtOH/95% water gave wet and dry μTBS of 53.0±2.3 and 55.7±5.1MPa (p>0.05). Cross-linking demineralized dentin with 5% GSE increased stiffness of dentin and decreased collagen degradation (p<0.05). SIGNIFICANCE 5% GSE pretreatment of acid-etched dentin for 1min permits the dentin to be completely air-dried without lowering bond strength.
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Abedin F, Ye Q, Song L, Ge X, Camarda K, Spencer P. Effect of Partition of Photo-initiator Components and Addition of Iodonium Salt on the Photopolymerization of Phase-Separated Dental Adhesive. JOM (WARRENDALE, PA. : 1989) 2016; 68:1090-1099. [PMID: 27158215 PMCID: PMC4856225 DOI: 10.1007/s11837-016-1816-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 01/06/2016] [Indexed: 06/05/2023]
Abstract
The polymerization kinetics of physically separated hydrophobic- and hydrophilic-rich phases of a model dental adhesive have been investigated. The two phases were prepared from neat resin containing 2-hydroxyethyl methacrylate (HEMA) and bisphenol A glycerolate dimethacrylate (BisGMA) in the ratio of 45:55 (wt/wt). Neat resins containing various combinations of popular photo-initiating compounds, e.g., camphoquinone (CQ), ethyl 4-(dimethylamino)benzoate (EDMAB), 2-(dimethylamino)ethyl methacrylate (DMAEMA) and diphenyliodonium hexafluorophosphate (DPIHP) were prepared. To obtain the two phases 33 wt% of deuterium oxide (D2O) was added to the neat resins. This amount of D2O exceeded the miscibility limit for the resins. The concentration of each component of the photo-initiating system in the two phases was quantified by HPLC. When combined with CQ, DMAEMA is less efficient as a co-initiator compared to EDMAB. The addition of DPIHP as the third component into either CQ/EDMAB or CQ/DMAEMA photo-initiating systems leads to comparable performance in both the hydrophobic- and hydrophilic-rich phases. The addition of the iodonium salt significantly improved the photopolymerization of the hydrophilic-rich phase; the hydrophilic-rich phase exhibited extremely poor polymerization when the iodonium salt was not included in the formulation. The partition concentration of EDMAB in the hydrophilic-rich phase was significantly lower than that of DMAEMA or DPIHP. This study indicates the need for a combination of hydrophobic/hydrophilic photosensitizer and addition of iodonium salt to improve polymerization within the hydrophilic-rich phase of the dental adhesive.
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Affiliation(s)
- Farhana Abedin
- Bioengineering Research Center, The University of Kansas, Lawrence, KS; Bioengineering Graduate Program, The University of Kansas, Lawrence, KS
| | - Qiang Ye
- Bioengineering Research Center, The University of Kansas, Lawrence, KS
| | - Linyong Song
- Bioengineering Research Center, The University of Kansas, Lawrence, KS
| | - Xueping Ge
- Bioengineering Research Center, The University of Kansas, Lawrence, KS
| | - Kyle Camarda
- Department of Chemical and Petroleum Engineering, The University of Kansas, Lawrence, KS
| | - Paulette Spencer
- Bioengineering Research Center, The University of Kansas, Lawrence, KS; Department of Mechanical Engineering, The University of Kansas, Lawrence, KS
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Abedin F, Ye Q, Camarda K, Spencer P. Impact of light intensity on the polymerization kinetics and network structure of model hydrophobic and hydrophilic methacrylate based dental adhesive resin. J Biomed Mater Res B Appl Biomater 2015; 104:1666-1678. [PMID: 26340329 DOI: 10.1002/jbm.b.33517] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 07/30/2015] [Accepted: 08/23/2015] [Indexed: 11/05/2022]
Abstract
The impact of light intensity on the degree of conversion (DC), rate of polymerization and network structure was investigated for hydrophobic and hydrophilic dental adhesive resins. Two and three component photoinitiating (PI) systems were used in this study. Low light intensities had a negative impact on the polymerization efficiency for the hydrophilic resin with 2 component PI system. Incorporation of iodonium salt in the hydrophilic resin significantly improved the polymerization efficiency of the HEMA/BisGMA system and led to a substantial DC, even at low light intensities. The results suggested that shorter polymer chains were formed in the presence of iodonium salt. It appears that there is little or no impact of light intensity on the polymer structure of the 2 component PI system. Light intensity has subtle impact on the polymer structure of the 3 component PI system. In the case of the hydrophobic resin, the polymer is so highly cross-linked that the presence of shorter chains for the 3 component PI system does not cause a decrease in the glass transition temperature (Tg ) when compared to the 2 component PI system. For the hydrophilic resin, the presence of shorter polymer chains in the 3 component PI system reduces the Tg when compared with the corresponding 2 component PI system. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1666-1678, 2016.
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Affiliation(s)
- Farhana Abedin
- Bioengineering Graduate Program, The University of Kansas, Lawrence, Kansas, 66045.,Bioengineering Research Center, The University of Kansas, Lawrence, Kansas, 66045
| | - Qiang Ye
- Bioengineering Research Center, The University of Kansas, Lawrence, Kansas, 66045.
| | - Kyle Camarda
- Department of Chemical and Petroleum Engineering, The University of Kansas, Lawrence, Kansas, 66045
| | - Paulette Spencer
- Bioengineering Research Center, The University of Kansas, Lawrence, Kansas, 66045.,Department of Mechanical Engineering, The University of Kansas, Lawrence, Kansas, 66045
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