Dataset Information

Probing the neutralization behavior of zwitterionic monomer-containing dental adhesive.

ABSTRACT: To investigate the polymerization kinetics, neutralization behavior, and mechanical properties of amine-functionalized dental adhesive cured in the presence of zwitterionic monomer, methacryloyloxyethyl phosphorylcholine (MPC).The control adhesive was a mixture based on HEMA/BisGMA/2-N-morpholinoethyl methacrylate (MEMA) (40/30/30, w/w/w). The control and experimental formulations containing MPC were characterized with regard to water miscibility of liquid resins, photopolymerization kinetics, water sorption and solubility, dynamic mechanical properties and leachables from the polymers (aged in ethanol). The neutralization behavior of the adhesives was determined by monitoring the pH of lactic acid (LA) solution.The water miscibility decreased with increasing MPC amount. The water sorption of experimental copolymer specimen was greater than the control. The addition of 8wt% water led to improved photo-polymerization efficiency for experimental formulations at MPC of 2.5 and 5wt%, and significant reduction in the cumulative amounts of leached HEMA, BisGMA, and MEMA, i.e. 90, 60 and 50% reduction, respectively. The neutralization rate of MPC-containing adhesive was faster than control. The optimal MPC concentration in the formulations was 5wt%.Incompatibility between MEMA and MPC led to a decrease in water miscibility of the liquid resins. Water (at 8wt%) in the MPC-containing formulations (2.5-5wt% MPC) led to higher DC, faster RPmax and significant reduction in leached HEMA, BisGMA, and MEMA. The neutralization rate was enhanced with the addition of MPC in the amine-containing formulation. Promoting the neutralization capability of dentin adhesives could play an important role in reducing recurrent decay at the composite/tooth interface.

SUBMITTER: Song L

PROVIDER: S-EPMC5480395 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature

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Probing the neutralization behavior of zwitterionic monomer-containing dental adhesive.

Song Linyong L Ye Qiang Q Ge Xueping X Misra Anil A Tamerler Candan C Spencer Paulette P

Dental materials : official publication of the Academy of Dental Materials 20170331 5

<h4>Objective</h4>To investigate the polymerization kinetics, neutralization behavior, and mechanical properties of amine-functionalized dental adhesive cured in the presence of zwitterionic monomer, methacryloyloxyethyl phosphorylcholine (MPC).<h4>Methods</h4>The control adhesive was a mixture based on HEMA/BisGMA/2-N-morpholinoethyl methacrylate (MEMA) (40/30/30, w/w/w). The control and experimental formulations containing MPC were characterized with regard to water miscibility of liquid resin ...[more]

PMID: 28366234

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Project description:Dental adhesives are vital for the success of dental restorations. The objective of this study is to make strong and durable dental adhesives that are free from 2 symbolic methacrylate-based dental resins-2-bis[4-(2-hydroxy-3-methacryl-oxypropoxy)-phenyl]-propane (Bis-GMA) and 2-hydroxyethyl-methacrylate (HEMA)-and have equivalent/improved bonding strength and durability. We formulated, prepared, and evaluated 2 dental adhesives using mixtures of a hydrolytically stable ether-based monomer, triethylene glycol divinylbenzyl ether (TEG-DVBE), with urethane dimethacrylate (UDMA) or pyromellitic glycerol dimethacrylate. These adhesives were composed of equimolar ester-/ether-based vinyl functional groups. They were compared with Bis-GMA/HEMA-based commercial and experimental dental adhesives in terms of shear bond strength and microtensile bond strength (µTBS) to human dentin and the µTBS bond stability under extended thermocycling challenges. In addition, the resins' infiltration to dentin tubules, mechanical performance, and chemical properties were assessed by scanning electron microscopy, ISO standard flexural strength and modulus measurements, contact angle measurements, and water sorption/solubility measurements. The hybrid TEG-DVBE-containing dental adhesives generated equivalent shear bond strength and µTBS in comparison with the controls. Significantly, these adhesives outperformed the controls after being challenged by 10,000 thermocycles between 5 °C and 55 °C. Water contact angle measurements suggested that the hybrid dental adhesives were relatively more hydrophobic than the Bis-GMA/HEMA controls. However, both TEG-DVBE-containing adhesives developed more and deeper resin tags in dentin tubules and formed thicker hybrid layers at the composite-dentin interface. Furthermore, the water solubility of UDMA/TEG-DVBE resins was reduced approximately 89% in comparison with the Bis-GMA/HEMA controls. The relatively hydrophobic adhesives that achieved equivalent/enhanced bonding performance suggest great potentials in developing dental restoration with extended service life. Furthermore, the TEG-DVBE-containing materials may find wider dental applications and broader utility in medical device development.

Project description:ObjectiveAssess the ability of an antimicrobial drug-releasing resin adhesive, containing octenidine dihydrochloride (OCT)-silica co-assembled particles (DSPs), to enhance the biostability and preserve the interfacial fracture toughness (FT) of composite restorations bonded to dentin. Enzyme-catalyzed degradation compromises the dental restoration-tooth interface, increasing cariogenic bacterial infiltration. In addition to bacterial ingress inhibition, antimicrobial-releasing adhesives may exhibit direct interfacial biodegradation inhibition as an additional benefit.MethodsMini short-rod restoration bonding specimens with total-etch adhesive with/without 10% wt. DSPs were made. Interfacial fracture toughness (FT) was measured as-manufactured or post-incubation in simulated human salivary esterase (SHSE) for up to 6-months. Effect of OCT on SHSE and whole saliva/bacterial enzyme activity was assessed. Release of OCT outside the restoration interface was assessed.ResultsNo deleterious effect of DSPs on initial bonding capacity was observed. Aging specimens in SHSE reduced FT of control but not DSP-adhesive-bonded specimens. OCT inhibited SHSE degradation of adhesive monomer and may inhibit endogenous proteases. OCT inhibited bacterial esterase and collagenase. No endogenous collagen breakdown was detected in the present study. OCT increased human saliva degradative esterase activity below its minimum inhibitory concentration towards S. mutans (MIC), but inhibited degradation above MIC. OCT release outside restoration margins was below detection.SignificanceDSP-adhesive preserves the restoration bond through a secondary enzyme-inhibitory effect of released OCT, which is virtually confined to the restoration interface microgap. Enzyme activity modulation may produce a positive-to-negative feedback switch, by increasing OCT concentration via biodegradation-triggered release to an effective dose, then subsequently slowing degradation and degradation-triggered release.

Project description:PurposeThe aim was to assess monomer conversion, dimensional stability, flexural strength / modulus, surface apatite precipitation and wear of mono / tri calcium phosphate (CaP) and polylysine (PLS)-containing dental composites. These were formulated using a new, high molecular weight, fluid monomer phase that requires no polymerisation activator.Materials and methodsUrethane and Polypropylene Glycol Dimethacrylates were combined with low levels of an adhesion promoting monomer and a light activated initiator. This liquid was mixed with a hybrid glass containing either 10 wt% CaP and 1 wt% PLS (F1) or 20 wt% CaP and 2 wt% PLS (F2). Powder to liquid mass ratio was 5:1. Commercial controls included Gradia Direct Posterior (GD) and Filtek Z250 (FZ). Monomer conversion and polymerisation shrinkage were calculated using Fourier Transform Infrared (FTIR). Subsequent volume increases in water over 7 weeks were determined using gravimetric studies. Biaxial flexural strength (BFS) / modulus (BFM) reduction and surface apatite precipitation upon 1 and 4 weeks immersion in water versus simulated body fluid (SBF) were assessed using a mechanical testing frame and scanning electron microscope (SEM). Mass / volume loss and surface roughness (Ra) following 7 weeks water immersion and subsequent accelerated tooth-brush abrasion were examined using gravimetric studies and profilometer.ResultsF1 and F2 exhibited much higher monomer conversion (72%) than FZ (54%) and low calculated polymerization shrinkage (2.2 vol%). Final hygroscopic expansions decreased in the order; F2 (3.5 vol%) > F1 (1.8 vol%) ~ Z250 (1.6 vol%) > Gradia (1.0 vol%). BFS and BFM were unaffected by storage medium type. Average BFS / BFM upon 4 weeks immersion reduced from 144 MPa / 8 GPa to 107 MPa / 5 GPa for F1 and 105 MPa / 6 GPa to 82 MPa / 4 GPa for F2. Much of this change was observed in the first week of immersion when water sorption rate was high. Surface apatite layers were incomplete at 1 week, but around 2 and 15 micron thick for F1 and F2 respectively following 4 weeks in SBF. Mass and volume loss following wear were equal. Average results for F1 (0.5%), F2 (0.7%), and FZ (0.5%) were comparable but lower than that of GD (1%). Ra, however, decreased in the order; F1 (15 ?m) > F2 (11 ?m) > GD (9 ?m) > FZ (5 ?m).ConclusionsHigh monomer conversion in combination with large monomer size and lack of amine activator should improve cytocompatibility of the new composites. High monomer molecular weight and powder content enables low polymerisation shrinkage despite high conversion. Increasing active filler provides enhanced swelling to balance shrinkage, which, in combination with greater surface apatite precipitation, may help seal gaps and reduce bacterial microleakage. High monomer conversion also ensures competitive mechanical / wear characteristics despite enhanced water sorption. Furthermore, increased active filler could help reduce surface roughness upon wear.

Project description:Antibacterial adhesives have favorable prospects to inhibit biofilms and secondary caries. The objectives of this study were to investigate the antibacterial effect of dental adhesives containing dimethylaminododecyl methacrylate (DMADDM) on different bacteria in controlled multispecies biofilms and its regulating effect on development of biofilm for the first time. Antibacterial material was synthesized, and Streptococcus mutans, Streptococcus gordonii, and Streptococcus sanguinis were chosen to form multispecies biofilms. Lactic acid assay and pH measurement were conducted to study the acid production of controlled multispecies biofilms. Anthrone method and exopolysaccharide (EPS):bacteria volume ratio measured by confocal laser scanning microscopy were performed to determine the EPS production of biofilms. The colony-forming unit counts, scanning electron microscope imaging, and dead:live volume ratio decided by confocal laser scanning microscopy were used to study the biomass change of controlled multispecies biofilms. The TaqMan real-time polymerase chain reaction and fluorescent in situ hybridization imaging were used to study the proportion change in multispecies biofilms of different groups. The results showed that DMADDM-containing adhesive groups slowed the pH drop and decreased the lactic acid production noticeably, especially lactic acid production in the 5% DMADDM group, which decreased 10- to 30-fold compared with control group (P < 0.05). EPS was reduced significantly in 5% DMADDM group (P < 0.05). The DMADDM groups reduced the colony-forming unit counts significantly (P < 0.05) and had higher dead:live volume ratio in biofilms compared with control group (P < 0.05). The proportion of S. mutans decreased steadily in DMADDM-containing groups and continually increased in control group, and the biofilm had a more healthy development tendency after the regulation of DMADDM. In conclusion, the adhesives containing DMADDM had remarkable antimicrobial properties to serve as "bioactive" adhesive materials and revealed its potential value for antibiofilm and anticaries clinical applications.

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Probing the neutralization behavior of zwitterionic monomer-containing dental adhesive.

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Probing the neutralization behavior of zwitterionic monomer-containing dental adhesive.

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