-
The Angle Orthodontist Sep 2014To quantify, with high-pressure liquid chromatography (HPLC), the amount of residual monomer leached from different orthodontic acrylic materials prepared with two... (Comparative Study)
Comparative Study
OBJECTIVE
To quantify, with high-pressure liquid chromatography (HPLC), the amount of residual monomer leached from different orthodontic acrylic materials prepared with two different manipulation methods.
MATERIALS AND METHODS
Eighty cylindrical specimens (5 × 25 mm) were divided into eight groups (n = 10). The specimens were prepared with four acrylic materials-Orthocryl Neon Blue (Dentaurum), Orthocryl EQ (Dentaurum), Orthoplast (Vertex), and O-80 (Imicryl)-and with two different manipulation methods: doughing and spray-on. HPLC measurements were made at intervals of 2 hours, 6 hours, 1 day, 1 week, and 3 months. One-way analysis of variance (ANOVA) and Tukey's honestly significant difference multiple-comparison test were used to assess the amount of monomer eluted from the various groups. To assess the differences within each group over the various periods, repeated-measures ANOVA and paired t-tests were used.
RESULTS
Statistically significant differences were found within the groups in the amount of residual monomer in the specimens at different time intervals (P < .001). HPLC showed statistically significant differences among the groups (P < .05) in the amount of eluted monomer. Evaluation of the manipulation techniques showed that the monomer release rate was higher in the specimens prepared with the doughing method. When the four acrylic materials were compared, the specimens made from Orthoplast (Vertex) showed the highest rate of monomer release with both manipulation techniques.
CONCLUSION
The spray-on method can be recommended to clinicians for the preparation of orthodontic appliances.
Topics: Acrylic Resins; Aerosols; Chromatography, High Pressure Liquid; Cross-Linking Reagents; Dental Materials; Humans; Materials Testing; Methacrylates; Methylmethacrylate; Methylmethacrylates; Orthodontic Appliances; Polymerization; Polymers; Polymethyl Methacrylate; Temperature; Terpenes; Time Factors; Viscosity
PubMed: 24601878
DOI: 10.2319/060713-435.1 -
Journal of Applied Oral Science :... Aug 2011Residual methyl methacrylate (MMA) may leach from the acrylic resin denture bases and have adverse effects on the oral mucosa. This in vitro study evaluated and...
Effect of leaching residual methyl methacrylate concentrations on in vitro cytotoxicity of heat polymerized denture base acrylic resin processed with different polymerization cycles.
OBJECTIVES
Residual methyl methacrylate (MMA) may leach from the acrylic resin denture bases and have adverse effects on the oral mucosa. This in vitro study evaluated and correlated the effect of the leaching residual MMA concentrations ([MMA]r) on in vitro cytotoxicity of L-929 fibroblasts.
MATERIAL AND METHODS
A total of 144 heat-polymerized acrylic resin specimens were fabricated using 4 different polymerization cycles: (1) at 74ºC for 9 h, (2) at 74ºC for 9 h and terminal boiling (at 100ºC) for 30 min, (3) at 74ºC for 9 h and terminal boiling for 3 h, (4) at 74ºC for 30 min and terminal boiling for 30 min. Specimens were eluted in a complete cell culture medium at 37ºC for 1, 2, 5 and 7 days. [MMA]r in eluates was measured using high-performance liquid chromatography. In vitro cytotoxicity of eluates on L-929 fibroblasts was evaluated by means of cell proliferation using a tetrazolium salt XTT (sodium 3´-[1-phenyl-aminocarbonyl)-3,4-tetrazolium]bis(4-methoxy-6-nitro)benzenesulphonic acid) assay. Differences in [MMA]r of eluates and cell proliferation values between polymerization cycles were statistically analyzed by Kruskal-Wallis, Friedman and Dunn's multiple comparison tests. The correlation between [MMA]r of eluates and cell proliferation was analyzed by Pearson's correlation test (p<0.05).
RESULTS
[MMA]r was significantly (p<0.001) higher in eluates of specimens polymerized with cycle without terminal boiling after elution of 1 and 2 days. Cell proliferation values for all cycles were significantly (p<0.01) lower in eluates of 1 day than those of 2 days. The correlation between [MMA]r and cell proliferation values was negative after all elution periods, showing significance (p<0.05) for elution of 1 and 2 days. MMA continued to leach from acrylic resin throughout 7 days and leaching concentrations markedly reduced after elution of 1 and 2 days.
CONCLUSION
Due to reduction of leaching residual MMA concentrations, use of terminal boiling in the polymerization process for at least 30 min and water storage of the heat-polymerized denture bases for at least 1 to 2 days before denture delivery is clinically recommended for minimizing the residual MMA and possible cytotoxic effects.
Topics: Acrylic Resins; Cell Culture Techniques; Cell Proliferation; Chromatography, High Pressure Liquid; Denture Bases; Fibroblasts; Hot Temperature; Materials Testing; Methylmethacrylate; Polymerization; Time Factors
PubMed: 21956586
DOI: 10.1590/s1678-77572011005000002 -
Journal of Endodontics Feb 2014MTA Plus is a new calcium silicate cement with unknown cytotoxicity characteristics. The objectives of this study were to examine the effect of MTA Plus on the... (Comparative Study)
Comparative Study
INTRODUCTION
MTA Plus is a new calcium silicate cement with unknown cytotoxicity characteristics. The objectives of this study were to examine the effect of MTA Plus on the viability, apoptosis/necrosis profile, and oxidative stress levels of rat odontoblast-like cells.
METHODS
MDPC-23 cells were exposed to gray and white MTA Plus (GMTAP, WMTAP), gray and white ProRoot MTA (GMTA, WMTA) cements, or their eluents. The cells were evaluated for (1) cell viability by using XTT assay, (2) apoptosis/necrosis by using flow cytometry and confocal laser scanning microscopy, and (3) oxidative stress by measuring reactive oxygen species.
RESULTS
XTT assay showed that all test cements exhibited marked initial cytotoxicity that decreased with time. By the end of the third week, GMTAP and GMTA were comparable to untreated cells (negative control) in terms of cell viability, whereas WMTAP and WMTA were significantly lower than the untreated cells. Apoptosis/necrosis profiles of cells exposed to WMTAP and GMTAP were not significantly different from untreated cells, whereas cells exposed to WMTA and GMTA showed significantly less viable cells. All experimental groups exhibited reduction of intracellular reactive oxygen species formation compared with untreated cells, although cells exposed to WMTA were not significantly different from untreated cells.
CONCLUSIONS
Both the gray and white versions of MTA Plus possess negligible in vitro cytotoxic risks that are time and dilution dependent. They enrich the spectrum of hydraulic calcium silicate cements currently available to clinicians for endodontic applications.
Topics: Aluminum Compounds; Animals; Apoptosis; Biocompatible Materials; Calcium Compounds; Cell Culture Techniques; Cell Line; Cell Survival; Drug Combinations; Flow Cytometry; Indicators and Reagents; Materials Testing; Methylmethacrylates; Microscopy, Confocal; Necrosis; Odontoblasts; Oxidative Stress; Oxides; Rats; Reactive Oxygen Species; Silicates; Tetrazolium Salts; Time Factors; Zinc Oxide-Eugenol Cement
PubMed: 24461414
DOI: 10.1016/j.joen.2013.07.009 -
Neurologia Medico-chirurgica 2015Eudragit-E was originally developed as a non-adhesive liquid embolic material in the late 1990s and is a copolymer of methyl and butyl methacrylate and...
Eudragit-E was originally developed as a non-adhesive liquid embolic material in the late 1990s and is a copolymer of methyl and butyl methacrylate and dimethylaminoethyl methacrylate that is dissolved in ethanol and iopamidol. This material has been used for endovascular embolization of brain arteriovenous malformations (AVMs) for some time but is currently not widely used. Because safety and feasibility of Eudragit-E has not been well documented, we here report our experience using this material for treating 22 human brain AVMs. From June 1998 to February 2014, 30 endovascular procedures using Eudragit-E were performed to treat 22 patients, including 14 men and 8 women with a mean age of 41.1 years (15-70 years). The mean follow-up period was 56 months (12-129 months), and the Spetzler-Martin grades were I (4 patients), II (9 patients), III (5 patients), and IV (4 patients). Residual AVMs were treated with stereotactic radiosurgery or surgery. The rate of complete obliteration with embolization alone was 27.3%. The overall obliteration rate after endovascular embolization with/without subsequent stereotactic radiosurgery or surgery was 72.7%. Eudragit-E caused two cases of cerebral infarction. One case of intracerebral hemorrhage due to postoperative hemodynamic changes also occurred. The rate of complications directly related to embolization was 10.0%. The safety and effectiveness of Eudragit-E embolization were satisfactory.
Topics: Adolescent; Adult; Aged; Embolization, Therapeutic; Endovascular Procedures; Female; Humans; Intracranial Arteriovenous Malformations; Male; Methylmethacrylates; Middle Aged; Retrospective Studies; Treatment Outcome; Young Adult
PubMed: 25739432
DOI: 10.2176/nmc.oa.2014-0287 -
International Journal of Nanomedicine 2018Nanoparticles are increasingly used as drug carriers for oral administration. The delivery of drug molecules is largely dependent on the interaction of nanocarriers and...
INTRODUCTION
Nanoparticles are increasingly used as drug carriers for oral administration. The delivery of drug molecules is largely dependent on the interaction of nanocarriers and gastrointestinal (GI) mucus, a critical barrier that regulates drug absorption. It is therefore important to understand the effects of physical and chemical properties of nanocarriers on the interaction with GI mucus. Unfortunately, most of the nanoparticles are unable to be prepared with satisfactory structural monodispersity to comprehensively investigate the interaction. With controlled size, shape, and surface chemistry, copolymers are ideal candidates for such purpose.
MATERIALS AND METHODS
We synthesized a series of diblock copolymers via the atom transfer radical polymerization method and investigated the GI mucus permeability in vitro and in vivo.
RESULTS
Our results indicated that uncharged and hydrophobic copolymers exhibited enhanced GI absorption.
CONCLUSION
These results provide insights into developing optimal nanocarriers for oral administration.
Topics: Administration, Oral; Animals; Caco-2 Cells; Drug Carriers; Humans; Hydrophobic and Hydrophilic Interactions; Indoles; Intestinal Absorption; Intestinal Mucosa; Male; Methacrylates; Methylmethacrylates; Mice; Nanoparticles; Nylons; Particle Size; Polymers; Propionates; Tissue Distribution
PubMed: 29805260
DOI: 10.2147/IJN.S160651 -
Journal of Biomedical Materials... Nov 2009A new trimethacrylate monomer with urethane-linked groups, 1,1,1-tri-[4-(methacryloxyethylamino-carbonyloxy)-phenyl]ethane (MPE), was synthesized, characterized, and...
A new trimethacrylate monomer with urethane-linked groups, 1,1,1-tri-[4-(methacryloxyethylamino-carbonyloxy)-phenyl]ethane (MPE), was synthesized, characterized, and used as a comonomer in dentin adhesives. Dentin adhesives containing 2-hydroxyethyl methacrylate (HEMA, 45% w/w) and 2,2-bis[4(2-hydroxy-3-methacryloyloxy-propyloxy)-phenyl] propane (BisGMA, 30% w/w) in addition to MPE (25% w/w) were formulated with H(2)O at 0 (MPE0), 8 (MPE8), and 16 wt % water (MPE16) to simulate the wet demineralized dentin matrix and compared with controls [HEMA /BisGMA, 45/55 w/w, at 0 (C0), 8 (C8), and 16 wt % water (C16)]. The new adhesive showed a degree of double bond conversion and mechanical properties comparable with control, with good penetration into the dentin surface and a uniform adhesive/dentin interface. On exposure to porcine liver esterase, the net cumulative methacrylic acid (MAA) released from the new adhesives was dramatically (p < 0.05) decreased relative to the control, suggesting that the new monomer improves esterase resistance.
Topics: Absorbable Implants; Acrylic Resins; Adhesiveness; Adhesives; Dental Materials; Dentin; Enzymes; Esterases; Hydrolysis; Magnetic Resonance Spectroscopy; Materials Testing; Methylmethacrylates; Microscopy, Electron, Scanning; Staining and Labeling; Stress, Mechanical; Urethane
PubMed: 19582843
DOI: 10.1002/jbm.b.31430 -
Journal of Dental Research Nov 2014Resin monomers (RMs) are inflammatory agents and are thought to cause allergic contact dermatitis (ACD). However, mouse models are lacking, possibly because of the weak...
Resin monomers (RMs) are inflammatory agents and are thought to cause allergic contact dermatitis (ACD). However, mouse models are lacking, possibly because of the weak antigenicities of RMs. We previously reported that inflammatory substances can promote the allergic dermatitis (AD) induced by intradermally injected nickel (Ni-AD) in mice. Here, we examined the effects of RMs on Ni-AD. To sensitize mice to Ni, a mixture containing non-toxic concentrations of NiCl2 and an RM [either methyl methacrylate (MMA) or 2-hydroxyethyl methacrylate (HEMA)] was injected intraperitoneally or into ear-pinnae intradermally. Ten days later, a mixture containing various concentrations of NiCl2 and/or an RM was intradermally injected into ear-pinnae, and ear-swelling was measured. In adoptive transfer experiments, spleen cells from sensitized mice were transferred intravenously into non-sensitized recipients, and 24 h later NiCl2 was challenged to ear-pinnae. Whether injected intraperitoneally or intradermally, RM plus NiCl2 mixtures were effective in sensitizing mice to Ni. AD-inducing Ni concentrations were greatly reduced in the presence of MMA or HEMA (at the sensitization step from 10 mM to 5 or 50 µM, respectively, and at the elicitation step from 10 µM to 10 or 100 nM, respectively). These effects of RMs were weaker in IL-1-knockout mice and in macrophage-depleted mice. Cell-transfer experiments in IL-1-knockout mice indicated that both the sensitization and elicitation steps depended on IL-1. Challenge with an RM alone did not induce allergic ear-swelling in mice given the same RM + NiCl2 10 days before the challenge. These results suggest that RMs act as adjuvants, not as antigens, to promote Ni-AD by reducing the AD-inducing concentration of Ni, and that IL-1 and macrophages are critically important for the adjuvant effects. We speculate that what were previously thought of as "RM-ACD" might include ACD caused by antigens other than RMs that have undergone promotion by the adjuvant effects of RMs.
Topics: Adaptive Immunity; Adjuvants, Immunologic; Animals; Blood Component Removal; Cell Transplantation; Clodronic Acid; Dental Materials; Dermatitis, Allergic Contact; Disease Models, Animal; Female; Immunization; Inflammation Mediators; Injections, Intradermal; Injections, Intraperitoneal; Interleukin-1alpha; Interleukin-1beta; Liposomes; Macrophages; Methacrylates; Methylmethacrylate; Mice; Mice, Inbred BALB C; Mice, Knockout; Nickel; Spleen
PubMed: 25252875
DOI: 10.1177/0022034514552674 -
Annals of African Medicine 2021Clinically, adhesion failure is the most critical problem because of the failure of the optimal bond between denture base and the soft liner.
BACKGROUND
Clinically, adhesion failure is the most critical problem because of the failure of the optimal bond between denture base and the soft liner.
OBJECTIVES
This study was performed to assess the tensile bond strength of two temporary soft liners to different denture base resins.
MATERIALS AND METHODS
Forty-eight blocks with 16 samples each of heat-cured denture base resin of three different types were fabricated from custom-made stainless steel die after de-waxing mold space. Surface roughening of each acrylic resin specimens which bonds with soft liners was done by abrading the surface and to this temporary soft liners (Perma soft denture liner and Pro soft denture liner) were bonded. The universal testing machine was used to test the tensile strength of bonded space. The results were statistically analyzed using the Statistical Software IBM SPSS Statistics for Windows, version 20.0. (Armonk, NY, USA: IBM Corp.) using the Chi-square test, Post hoc Tukey's HSD, and two way ANOVA tests.
RESULTS
It was observed that Perma soft was prevalent over Pro-soft denture liner on the basis of tensile bond strength with all three different types of denture base resins. Trevalon HI and acrylic composite exhibited better bond strength results with both Perma soft and GC Pro-soft denture liner as compared to other types of denture base resins.
CONCLUSION
Perma soft had a better bond strength compared to Pro-soft denture liner in bonding modified denture base and conventional resins.
Topics: Acrylic Resins; Dental Bonding; Denture Bases; Denture Liners; Humans; Materials Testing; Methylmethacrylates; Surface Properties; Tensile Strength
PubMed: 34213478
DOI: 10.4103/aam.aam_30_20 -
Dental Materials Journal 2012The cytotoxicity of nine soft and hard lining materials (Mollosil Plus, Ufi Gel SC, Visco-gel, Molloplast-B, GC Tissue Conditioner, Vertex Rapid Simplified, GC Reline...
The cytotoxicity of nine soft and hard lining materials (Mollosil Plus, Ufi Gel SC, Visco-gel, Molloplast-B, GC Tissue Conditioner, Vertex Rapid Simplified, GC Reline Hard, Vertex Self-Curing, Ufi Gel hard C) was evaluated using human gingival fibroblasts (HGFs). Twelve disk samples per lining material were prepared and incubated for 24, 48, 72, and 96 h. Cytotoxicity of each lining material's extract on cultured HGFs was measured using XTT assay. Data were analyzed using one-way ANOVA, post hoc Dunnett's T3 and Bonferroni tests at a significance level of p<0.05. At all incubation periods, all the hard lining materials (Vertex-SC, GC Reline Hard, Vertex-RS, and Ufi Gel hard C) showed cell viability higher than 90%. Among the soft lining materials, although there were no significant differences in cell viability among the different incubation periods for each lining material (p>0.05), autopolymerized acrylic-based GC Tissue Conditioner showed significantly lower cell viability than the other soft lining materials at each incubation period. Among the hard lining materials, there were no significant differences both among the materials and across all incubation periods for each lining material (p>0.05). In conclusion, all soft and hard liners exhibited good biocompatibility regardless of incubation time, except for GC Tissue Conditioner.
Topics: Acrylic Resins; Analysis of Variance; Biocompatible Materials; Cell Survival; Cells, Cultured; Denture Liners; Fibroblasts; Gingiva; Humans; Methylmethacrylates; Silicone Elastomers; Statistics, Nonparametric
PubMed: 23207219
DOI: 10.4012/dmj.2012-209 -
Brazilian Dental Journal 2011This study evaluated the release of glutaraldehyde from heat-polymerized acrylic resins subjected to disinfection followed by chemical and mechanical polishing. Ninety... (Comparative Study)
Comparative Study
This study evaluated the release of glutaraldehyde from heat-polymerized acrylic resins subjected to disinfection followed by chemical and mechanical polishing. Ninety disc-shaped specimens (15 x 4 mm), 30 per resin (Lucitone 550, QC-20 and Classico), were made and assigned to 2 groups according to the type of polishing. One side of each specimen was not polished and the other was either mechanically (n = 45) or chemically (n = 45) polished, and immersed in water at 50 °C for 1 h to allow the release of intrinsic substances and then kept in distilled water for 7 days. The specimens were disinfected by immersion in 2% glutaraldehyde for 10 min. After this period, 3 specimens from each group were immersed in water for 15, 30, 60, 120 and 240 min. For the 15-, 30-, 60-min immersions, 4 water exchanges were done at the end of period. High performance liquid chromatography (HPLC) was used to detect and quantify the glutaraldehyde released after each period. Data were analyzed statistically by two-way ANOVA and multiple comparisons were done by Tukey's and Scheffé's tests (α = 0.05). No glutaraldehyde release was observed from the specimens with chemical polishing at any of the immersion periods, while the mechanically polished specimens released glutaraldehyde. In the groups with water exchanges, Lucitone released more disinfectant in the 15-min period (0.040 μg/mL), Classico in the 30-min (0.021 μg/mL) and 60-min (0.018 μg/mL) periods, and QC-20 the same amount (-1.760 μg/mL) in all periods. In the groups without water exchanges, Lucitone released the highest amount of disinfectant (-1.370 μg/mL), differing significantly from QC-20 (0022 g/mL) and Classico (0019 g/mL), which were similar. The findings of this showed that chemically polished specimens from the 3 resin brands did not release glutaraldehyde after different periods of immersion, while glutaraldehyde release was observed from the mechanically polished specimens, especially from those made of Lucitone resin.
Topics: Acrylic Resins; Chromatography, High Pressure Liquid; Dental Disinfectants; Dental Materials; Dental Polishing; Disinfection; Glutaral; Hot Temperature; Humans; Immersion; Materials Testing; Methylmethacrylate; Polymerization; Polymethyl Methacrylate; Temperature; Time Factors; Water
PubMed: 22189645
DOI: 10.1590/s0103-64402011000600009