scholarly journals THE RESIDUAL MONOMER IN DENTAL ACRYLIC RESIN AND ITS ADVERSE EFFECTS

2013 ◽  
Vol 4 (1) ◽  
Author(s):  
Nedeljka Ivković ◽  
Djordje Božović ◽  
Siniša Ristić ◽  
Vladan Mirjanić ◽  
Olivera Janković
Keyword(s):  
Oral Cavity ◽  
Oral Mucosa ◽  
Acrylic Resin ◽  
Review Literature ◽  
Orthodontic Appliances ◽  
Residual Monomer ◽  
Acrylic Resins ◽  
Functional Efficiency ◽  
Clinically Significant ◽  
The One

Acrylic based resins are frequently used in daily dental practice. The most common use of the materials includes denture bases and denture liners, temporary crowns and orthodontic appliances. In the mouth, properties and functional efficiency of applied acrylic resins depend on internal factors related to the methods and conditions of polymerization and on external factors that are related to the environment in which the material is placed. Residual monomer, which is released as a result of interaction of both sets of factors is often associated with irritation, inflammatory and allergic reactions of oral mucosa. The aim of this paper is to review literature dealing with the conditions of polymerization and biodegradation of acrylic resins under certain conditions in the oral cavity and their impact on oral health (reviewed literature available on Medline database during the past two decades.) Conclusion: Methods and conditions of acrylate polymerization, on the one hand, and properties of saliva, chewing and the presence of microorganisms in the oral cavity, on the other hand, can be considered responsible for the release of residual monomers. Clinically significant events followed by redness and erosion of the oral mucosa, burning sensation and burning mucosa and tongue, may be due to the effects of released, potentially cytotoxic, residual monomers.

The Effect of Bleach Liquid and Household Cleaner on Surface Hardness and Roughness of Acrylic Base of Orthodontic Appliances

2021 ◽  
Author(s):  
Saeed Noorollahian ◽  
Farinaz Shirban ◽  
Vahid Mojiri
Keyword(s):  
Surface Roughness ◽  
Hydrochloric Acid ◽  
Sodium Hypochlorite ◽  
Surface Hardness ◽  
Acrylic Resin ◽  
Liquid Sodium ◽  
P Value ◽  
Orthodontic Appliances ◽  
Acrylic Resins ◽  
Significant Difference

Introduction: The daily use of orthodontic removable plates can interfere with the self-cleansing function of the mouth. Although various techniques have been proposed for cleaning removable orthodontic appliances, there is no consensus on the use of a safe method that preserves the physical properties of the appliance. This study aimed to investigate the effect of using hydrochloric acid (10%, for removal of mineral deposits) and sodium hypochlorite (5.25%, to remove organic matter and discolorations) on surface hardness and roughness of self-cure orthodontic acrylic resins. Materials & Methods: This cross-sectional laboratory study was conducted in the fall of 2017 at Isfahan University of Medical science and Isfahan University of Technology. In this study two orthodontic acrylic resins (Orthocryl® and Acropars®) were used. Eighty samples (12×10×3 mm) from each one were fabricated and divided into four groups (n = 20). Group 1: 15 minutes immersion in household cleaner liquid (Hydrochloric acid, 10%) followed by15 minutes immersion in household bleach liquid (Sodium Hypochlorite, 5.25%). In group 2, immersions were repeated just like group two times and in group 3, were done three times. Group 4 was as control and had no immersion. The surface hardness and roughness of samples were measured. Data were analyzed with Two Way ANOVA and the significance level was set at 0.05. Results: The number of immersion procedures did not significantly affect the surface hardness (p value = 0.958) and surface roughness (p value = 0.657) in the different study groups. There was no significant difference in the surface hardness between the two acrylic resin brands (p value = 0.077); however, Acropars acrylic resin samples exhibited significantly higher surface roughness compared to the Orthocryl acrylic resin samples(p value < 0.001). Conclusion: 15 minutes of immersion in 10% HCl, followed by 15 minutes of immersion in 5.25% NaOCl and repetition of the procedure three times did not significantly affect the surface hardness and roughness of self-cured acrylic resins.

scholarly journals Surface morphology changes of acrylic resins during finishing and polishing phases

2013 ◽  
Vol 18 (6) ◽  
pp. 26-30 ◽  
Author(s):  
Glaucio Serra ◽  
Liliane Siqueira de Morais ◽  
Carlos Nelson Elias
Keyword(s):  
Surface Morphology ◽  
Acrylic Resin ◽  
Surface Finishing ◽  
Control Group ◽  
Orthodontic Appliances ◽  
Test Results ◽  
Good Surface ◽  
Acrylic Resins ◽  
Polishing Procedures ◽  
Removable Orthodontic Appliances

INTRODUCTION: The finishing and polishing phases are essential to improve smoothness and shining on the surface of acrylic resins used to make removable orthodontic appliances. A good surface finishing reduces roughness, which facilitates hygiene, prevents staining and provides greater comfort to the patients. OBJECTIVE: The aim of this paper was to analyze the changes on surface morphology of acrylic resins during finishing and polishing phases. METHODS: Thirty discs (10 mm in diameter and 5 mm in length) were made with acrylic resin and randomly divided into ten groups. The control group did not receive any treatment while the other groups received gradual finishing and polishing. The last group received the entire finishing and polishing procedures. Surface morphology was qualitatively analyzed through scanning electron microscopy and quantitatively analyzed through a laser profilometer test. RESULTS: The acrylic resin surfaces without treatment showed bubbles which were not observed in the subsequent phases. Wearing out with multilaminated burs, finishing with wood sandpaper and finishing with water sandpaper resulted in surfaces with decreasing irregularities. The surfaces that were polished with pumice and with low abrasive liquids showed high superficial smoothness. CONCLUSION: Highly smooth acrylic resin surfaces can be obtained after mechanical finishing and polishing performed with multilaminated burs, wood sandpaper, water sandpaper, pumice and low abrasive liquids.

Surface Microstructure Study of Self Cured Acrylic Resin after Immersion in Arabica Gayo Coffee

2020 ◽  
Vol 48 ◽  
pp. 62-69
Author(s):  
Viona Diansari ◽  
Subhaini ◽  
Arihta Putri
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Acid Content ◽  
Acrylic Resin ◽  
Polymer Chains ◽  
Surface Microstructure ◽  
Residual Monomer ◽  
Microstructure Observation ◽  
Acrylic Resins ◽  
Scanning Electron

The water absorption on self-cured acrylic resin is higher than the heat cured acrylic resin. Incoming water positions itself between the polymer chains and affects the surface microstructure of self-cured acrylic resin. The absorption of liquids such as Arabica Gayo coffee may aggravate the surface structure of self-cured acrylic resins due to their acid content. This study aims to find out the microstructure of self-cured acrylic resin surface after immersed in Arabica Gayo coffee for 2 and 7 days. This study used 5 specimens of self-cured acrylic resin (MeliodentTM) with size 10x10x1,5 mm3. Each specimen was immersed in aquades for 24 hours to reduce the residual monomer and then be given different immersion treatments. The immersion temperature used was 55°C. After immersion, surface microstructure observation was done using Scanning Electron Microscope (JEOL JSM 6510 LA). The images obtained were bubbles after being immersed in aquades for 2 days and more on day 7, micro porous after being immersed in Arabica Gayo coffee for 2 days and more on day 7 than untreated specimens. The conclusion of this study is micro porous formed more on the surface of self-cured acrylic resin along with the duration of self-cured acrylic resin immersion in Arabica Gayo coffee.

scholarly journals Incorporation of Chitosan Nanoparticles into a Cold-Cure Orthodontic Acrylic Resin: Effects on Mechanical Properties

Biomimetics ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 7
Author(s):  
Mostafa Shahabi ◽  
Sorour Movahedi Fazel ◽  
Abdolrasoul Rangrazi
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Impact Strength ◽  
Flexural Strength ◽  
Chitosan Nanoparticles ◽  
Antimicrobial Properties ◽  
Acrylic Resin ◽  
Orthodontic Appliances ◽  
Negative Effects ◽  
Acrylic Resins

Improvement of the antibacterial properties of acrylic resins, used in the construction of removable orthodontic appliances, is an important strategy to reduce the incidence of caries and oral diseases in orthodontic treatments. The addition of antimicrobial agents to acrylic resins is one of the effective methods to enhance the antimicrobial properties of these materials. However, one main concern is that modification of acrylic resin has negative effects on its mechanical properties. Recently, chitosan nanoparticles (NPs), as biocompatible and biodegradable polysaccharides with remarkable antimicrobial properties, have been used in different areas of dentistry and medicine. This study aimed to investigate the effects of adding chitosan NPs on the mechanical properties of a cold-cure orthodontic acrylic resin. The chitosan NPs were added to the acrylic resin in various weight percentages: 0% (control), 0.5%, 1%, 2%, and 4%. The flexural strength, compressive strength, Vickers microhardness, and impact strength measurements were performed for all five groups. The results showed that adding up to 1% (w/w) chitosan NPs to an acrylic resin had no significant negative effects on its flexural strength and compressive strength, while it decreased these parameters at weight percentages of 2% and 4% (w/w). The results also revealed that modification of acrylic resin with chitosan NPs up to 4% had no significant negative effects on the microhardness and impact strength of acrylic resin. In conclusion, the addition of chitosan NPs up to 1% (w/w) had no significant negative effects on the mechanical properties of cold-cure acrylic resin.

scholarly journals Effect of adding zinc oxide nanoparticles supported in 4A zeolite on antibacterial properties and flexural strength of self-curing acrylic resin used in removable orthodontic appliances

2021 ◽  
Vol 43 (3) ◽  
pp. 274-282
Author(s):  
Mahdiyeh Esmaeilzadeh ◽  
Baharak Divband ◽  
Fatemeh Yeganeh Sefidan ◽  
Mona Gholami ◽  
Mojgan Kachoei
Keyword(s):  
Flexural Strength ◽  
Antibacterial Properties ◽  
Acrylic Resin ◽  
Test Method ◽  
Bending Test ◽  
Orthodontic Appliances ◽  
X Ray ◽  
Acrylic Resins ◽  
4A Zeolite ◽  
Base Plates

Background: Self-curing acrylic resins, mainly composed of Polymethyl Methacrylate (PMMA), are widely used to manufacture removable orthodontic appliances. Self-curing acrylic resins have higher porosity than heat-curing acrylic resins leading to a susceptible place for microbial plaque colonization. Due to some of these microorganisms' activities, a very unpleasant odor is emitted from orthodontic base plates, which has adverse effects on patients' cooperation. This study aimed to investigate the antimicrobial properties of cold-curing PMMA acrylic resin containing ZnO nanoparticles supported in 4A zeolite and evaluating its mechanical properties. Methods: The synthesized nanocomposite ZnO/4A zeolite was added to SR Triplex® Cold orthodontic self-curing acrylic resin powder with 2wt% and 4wt% concentrations. X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), energy dispersive X-ray (EDX), MAP analysis, and Dynamic light scattering (DLS) were performed to investigate the sample's characteristics. Direct test method was used to assess the antibacterial properties of the fabricated acrylic samples against three bacterial strains Streptococcus mutans, Klebsiella Pnemoniae, and Esherichia coli. Flexural strength was evaluated by a three-point bending test, and One-way ANOVA and Tukey's post hoc test were used for statistical evaluation of data. The p-value of less than 0.05 was considered significant. Results: The addition of ZnO/4A in 2wt% and 4 wt% concentrations lead to more than 99% destruction of colonies in all three types of microorganisms. The mean flexural strength of acrylic specimens containing 2wt% and 4wt% of ZnO/4A significantly lower than the control group. Despite the considerable reduction, all mean values are greater than 50 MPa. Conclusion: The ZnO/4A zeolite nanocomposite due to its potent antibacterial properties and minimal toxicity can reduce the unfavorable odor of orthodontic base plates consequently increases patient cooperation and reaching the desired result. Method: The synthesized nanocomposite ZnO/4A zeolite was added to SR Triplex® Cold orthodontic self-curing acrylic resin powder with 2wt% and 4wt% concentrations. X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy(FE-SEM), energy dispersive X-ray (EDX), MAP analysis, and Dynamic light scattering (DLS) were performed to investigate the sample's characteristics. Direct test method was used to assess the antibacterial properties of the fabricated acrylic samples against three bacterial strains Streptococcus mutans, Klebsiella Pnemoniae, and Esherichia coli. Flexural strength was evaluated by a three-point bending test, and One-way ANOVA and Tukey's post hoc test were used for statistical evaluation of data. The p-value of less than 0.05 was considered significant. Results: The addition of ZnO/4A in 2wt% and 4 wt% concentrations lead to more than 99% destruction of colonies in all three types of microorganisms. The mean flexural strength of acrylic specimens containing 2wt% and 4wt% of ZnO/4A significantly lower than the control group. Despite the considerable reduction, all mean values are greater than 50 MPa. Conclusion: The addition of ZnO/4A zeolite nanocomposite due to its potent antibacterial properties and minimal toxicity can reduce the unfavorable odor of orthodontic base plates consequently increases patient cooperation and reaching the desired result.

scholarly journals Comparison of Fracture Resistance in Thermal and Self-Curing Acrylic Resins—An In Vitro Study

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1234
Author(s):  
António Sérgio Silva ◽  
Aurora Carvalho ◽  
Pedro Barreiros ◽  
Juliana de Sá ◽  
Carlos Aroso ◽  
...  
Keyword(s):  
Fracture Resistance ◽  
Research Work ◽  
Testing Machine ◽  
In Vitro Study ◽  
Dimensional Accuracy ◽  
Acrylic Resin ◽  
Thermosetting Resins ◽  
Acrylic Resins ◽  
The Difference

Thermal and self-curing acrylic resins are frequently and versatilely used in dental medicine since they are biocompatible, have no flavor or odor, have satisfactory thermal qualities and polishing capacity, and are easy and fast. Thus, given their widespread use, their fracture resistance behavior is especially important. In this research work, we comparatively analyzed the fracture resistance capacity of thermo and self-curing acrylic resins in vitro. Materials and Methods: Five prosthesis bases were created for each of the following acrylic resins: Lucitone®, ProBase®, and Megacryl®, which were submitted to different forces through the use of the CS® Dental Testing Machine, usually mobilized in the context of fatigue tests. To this end, a point was defined in the center of the anterior edge of the aforementioned acrylic resin bases, for which the peak tended until a fracture occurred. Thermosetting resins were, on average, more resistant to fracture than self-curable resins, although the difference was not statistically significant. The thermosetting resins of the Lucitone® and Probase® brands demonstrated behavior that was more resistant to fracture than the self-curing homologues, although the difference was not statistically significant. Thermosetting resins tended to be, on average, more resistant to fracture and exhibited the maximum values for impact strength, compressive strength, tensile strength, hardness, and dimensional accuracy than self-curing resins, regardless of brand.

Effect of Interchanging Liquid Components of Two Auto-Polymerizing Orthodontic Acrylic Resins in their Flexural Properties

2014 ◽  
Vol 1025-1026 ◽  
pp. 797-802 ◽  
Author(s):  
Tassanaporn Saen-Isara ◽  
Surachai Dechkunakorn ◽  
Niwat Anuwongnukroh ◽  
Toemsak Srikhirin ◽  
Siriporn Tanodekaew
Keyword(s):  
Setting Time ◽  
Acrylic Resin ◽  
Flexural Properties ◽  
Acrylic Resins

Objective: To evaluate the effects of interchanging the liquid components of two commercially available orthodontic auto-polymerizing acrylic resin in their flexural properties, clarity and setting time

Thorough QT Study to Evaluate the Effect of Zoliflodacin, a Novel Therapeutic for Gonorrhea, on Cardiac Repolarization in Healthy Adults

2021 ◽  
Author(s):  
Lori M. Newman ◽  
Martin Kankam ◽  
Aya Nakamura ◽  
Tom Conrad ◽  
John Mueller ◽  
...  
Keyword(s):  
Oral Dose ◽  
Single Oral Dose ◽  
Cardiac Repolarization ◽  
Cardiac Safety ◽  
Double Blind ◽  
Thorough Qt Study ◽  
Regulatory Guidelines ◽  
Clinically Significant ◽  
The One ◽  
Global Threat

Zoliflodacin is a novel spiropyrimidinetrione antibiotic being developed as single oral dose treatment to address the growing global threat of Neisseria gonorrhoeae . To evaluate the cardiac safety of zoliflodacin, a thorough QT/QTc (TQT) study was performed in healthy subjects. In this randomized, double-blind, placebo-controlled, 4-period crossover study, 72 subjects in a fasted state received a single dose of zoliflodacin 2 g (therapeutic), zoliflodacin 4 g (supratherapeutic), placebo, and moxifloxacin 400 mg as a positive comparator. Cardiac repolarization was measured by duration of the corrected QT interval by Fridericia’s formula (QTcF). At each time point up to 24 hours after zoliflodacin administration, the upper limit of the one-sided 95% confidence interval (CI) for the placebo-corrected change from the pre-dose baseline in QTcF (ΔΔQTcF) was less than 10 ms, indicating an absence of a clinically meaningful increase in QT prolongation. The lower limit of the one-sided multiplicity-adjusted 95% CI of ΔΔQTcF for moxifloxacin was longer than 5 ms at four time points from 1-4 hours after dosing, demonstrating adequate sensitivity of the QTc measurement. There were no clinically significant effects on heart rate, PR and QRS intervals, ECG morphology, or laboratory values. Treatment-emergent adverse events (AEs) were mild or moderate in severity and transient. This was a negative TQT study according to regulatory guidelines (E14) and confirms that a single oral dose of zoliflodacin is safe and well-tolerated. These findings suggest zoliflodacin is not proarrhythmic and contribute to the favorable assessment of cardiac safety for a single oral dose of zoliflodacin.

scholarly journals Water sorption of heat-polymerized acrylic resins processed in mono and bimaxillary flasks

2006 ◽  
Vol 17 (2) ◽  
pp. 122-125 ◽  
Author(s):  
Carolina B. Meloto ◽  
Laís R. Silva-Concílio ◽  
Cristiane Machado ◽  
Margarete C. Ribeiro ◽  
Fábio A. Joia ◽  
...  
Keyword(s):  
Water Sorption ◽  
Acrylic Resin ◽  
Microwave Energy ◽  
Water Bath ◽  
Acrylic Resins ◽  
Energy Processing ◽  
Group 3 ◽  
Group 2 ◽  
Student’S T ◽  
Group 1

This study evaluated water sorption in heat-polymerized acrylic resins processed in monomaxillary flasks by water bath and in bimaxillary flasks by microwave energy and water bath. Fifty heat-polymerized acrylic resin specimens were fabricated according to the 12th specification of the American Dental Association and assigned to 3 groups: group 1 was processed by water bath in monomaxillary metallic flask; group 2 was processed by microwave energy in bimaxillary PVC flask; and group 3 was processed by water bath in bimaxillary metallic flask. Specimens were submitted to water sorption test, means were calculated and analyzed statistically by Student's t-test. Means (in g/cm³) were: group 1 - 0.024085, group 2 - 0.025312 and group 3 - 0.022098. Microwave energy processing and the amount of stone and resin used in the bimaxillary PVC flask did not influence water sorption; specimens processed in bimaxillary metallic flask by water bath presented lower water sorption means, suggesting an inadequate polymerization of the acrylic resin mass.

scholarly journals Acrylic resin disinfection by peracetic acid and microwave energy

2015 ◽  
Vol 63 (3) ◽  
pp. 315-318 ◽  
Author(s):  
Carmen Beatriz Borges FORTES ◽  
Vicente Castelo Branco LEITUNE ◽  
Fabrício Mezzomo COLLARES ◽  
Nélio Bairros DORNELLES JUNIOR ◽  
Stéfani Becker RODRIGUES ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Microwave Irradiation ◽  
Incubation Period ◽  
Peracetic Acid ◽  
Acrylic Resin ◽  
Microwave Energy ◽  
The Other ◽  
Disinfection Methods ◽  
Acrylic Resins ◽  
Irradiation Power

Objective: The objective of this study was to evaluate the effectiveness of disinfection methods in microwave and immersion in peracetic acid in heat-cured, self-cured and microwave-cured acrylic resin, contaminated with Candida albicans. Methods: Five specimens were prepared for each type of acrylic resin. All were infected with Candida Albicans, incubated at 37°C for 24 hours. The group which underwent microwave energy was irradiated with a power of 840W for 1 minute and the other group underwent disinfection by soaking of 0.2% peracetic acid for 5 minutes. Results: All samples proved to be contaminated after the incubation period. After the different processes of disinfection, both immersion in 0.2% peracetic acid as microwave irradiation were effective in disinfection of the 3 types of acrylic resins contaminated by Candida Albicans. Conclusion: Concluded that soaking in 0,2% peracetic acid for 5 minutes with microwave irradiation power 840W for 1 minute are effective methods for disinfecting heat-cured acrylic resin, self-cured acrylic resin and microwave-cured acrylic resin, contaminated with Candida Albicans.

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