scholarly journals Antimicrobial properties, anti-virulence activities, and physico-mechanical characteristics of orthodontic adhesive containing C-phycocyanin: a promising application of natural products

Folia Medica ◽  
2021 ◽  
Vol 63 (1) ◽  
pp. 113-121
Author(s):  
Maryam Pourhajibagher ◽  
Abbas Bahador
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Antimicrobial Properties ◽  
Acrylic Resin ◽  
Inhibition Zone ◽  
Antimicrobial Activities ◽  
Microbial Biofilms ◽  
Growth Inhibition Zone ◽  
Orthodontic Adhesives ◽  
Acrylic Resins

Introduction: Antimicrobial orthodontic adhesives aim to reduce enamel demineralization, white spot lesions, and incipient tooth decay around bonded orthodontic brackets, but they should not imperil its mechanical properties.  Aim: To evaluate the antimicrobial and physico-mechanical properties of acrylic containing different concentrations of C-phycocyanin on Streptococcus mutans, Lactobacillus acidophilus, and Candida albicans. Materials and methods: The mechanical properties of acrylic resins were measured by flexural strength test after preparation of acrylic resin samples with concentrations of 1%, 2%, 5%, 7.5%, and 10% of C-phycocyanin. Then we evaluated the antimicrobial effects of acrylic resin containing the maximum concentration of C-phycocyanin with clinically acceptable flexural strength and the changes in expression of virulence factors. Results: The highest and lowest means of flexural strength were obtained in acrylic resins containing 0% and 10% concentrations of C-phycocyanin at 50.2±4.5 and 30.1±3.3 MPa, respectively. Adding 1%, 2%, and 5% of C-phycocyanin showed no significant decrease in flexural strength (p>0.05). The maximum mean diameter of the growth inhibition zone was observed around discs containing 5% of C-phycocyanin. Until day 30 of the study, no microbial biofilms were formed on any acrylic disc. Only microbial biofilms of C. albicans were able to form on discs containing 5% of C-phycocyanin at 90 days. 5% C-phycocyanin could significantly decrease the expression levels of gtfB, hsp16, and ALS9 6.1-, 7.3-, and 3.9-fold, respectively. Conclusions: It can be concluded that the most acceptable concentration of C-phycocyanin in acrylic resin is 5% based on the results of flexural strength tests and antimicrobial activities of acrylic resin containing various concentrations of C-phycocyanin.

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 Polytetrafluorethylene added to acrylic resins: mechanical properties

2010 ◽  
Vol 21 (1) ◽  
pp. 55-59 ◽  
Author(s):  
Fabiana Gouveia Straioto ◽  
Antonio Pedro Ricomini Filho ◽  
Alfredo Júlio Fernandes Neto ◽  
Altair Antoninha Del Bel Cury
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Flexural Strength ◽  
Flexural Modulus ◽  
Peak Load ◽  
Surface Hardness ◽  
Acrylic Resin ◽  
Denture Base ◽  
Standard Data ◽  
Acrylic Resins

The addition of different polymers, such as polytetrafluorethylene (PTFE), to denture base resins could be an option to modify acrylic resin mechanical properties. This study evaluated the surface hardness, impact and flexural strength, flexural modulus and peak load of 2 acrylic resins, one subjected to a long and another subjected to a short polymerization cycle, which were prepared with or without the addition of 2% PTFE. Four groups were formed according to the polymerization cycle and addition or not of PTFE. Forty specimens were prepared for each test (10 per group) with the following dimensions: hardness (30 mm diameter x 5 mm thick), impact strength (50 x 6 x 4 mm) and flexural strength (64 x 10 x 3.3 mm) test. The results of the flexural strength test allowed calculating flexural modulus and peak of load values. All tests were performed in accordance with the ISO 1567:1999 standard. Data were analyzed statistically by ANOVA and Tukey's test with the level of significance set at 5%. No statistically significant differences (p>0.05) were found for surface hardness. Flexural strength, impact strength and peak load were significantly higher (p<0.05) for resins without added PTFE. The flexural modulus of the acrylic resin with incorporated 2% PTFE polymerized by long cycle was significantly higher (p<0.05) than that of the other resins. Within the limits of this study, it may be concluded that the addition of PTFE did not improve the mechanical properties of the evaluated acrylic resins.

scholarly journals The PHYTOCHEMICALS, ANTIOXIDANT AND ANTIMICROBIAL PROPERTIES OF Senna alata AND Senna tora LEAF EXTRACTS AGAINST BACTERIAL STRAINS CAUSING SKIN INFECTIONS

2019 ◽  
Vol 2 (1) ◽  
pp. 19
Author(s):  
Murni Halim
Keyword(s):  
Leaf Extract ◽  
Antimicrobial Properties ◽  
Inhibition Zone ◽  
Antimicrobial Activities ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Leaf Extracts ◽  
Natural Drugs ◽  
Senna Alata

A study was carried out to screen for phytochemical constituents and assess the antioxidant and antimicrobial activities of Senna alata and Senna tora leaf extracts. The leaves were first dried at room temperature and 50°C in an oven prior to solvent extraction using ethanol and methanol. The in-vitro qualitative assays showed that both S. alata and S. tora leaf extracts contained bioactive and secondary metabolites components such as tannins, steroids, saponin, terpenoids, glycosides, flavonoids and phenols. The antioxidant activity and capacity test were carried out by conducting free radical of 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and Ferric reduction antioxidant plasma (FRAP) assays. Both assays showed S. tora leaf extract has higher antioxidant capacity than S. alata leaf extract. The efficacy of these leaf extracts were tested against skin pathogens through agar well diffusion method. S. alata extract showed an inhibition zone (1.15 – 1.59 mm) against Pseudomonas aeruginosa while S. tora extracts exhibited a strong antimicrobial activity against S. epidermidis (inhibition zone of 12 – 16.94 mm) followed by P. aeruginosa (inhibition zone of 1 – 1.59 mm). Nonetheless, no inhibition zone was observed for S. aureus by both leaf extracts. The phytochemicals and antioxidant constituents as well as inhibitory potential on skin pathogens possessed by S. alata and S. tora leave highlighted their potential utilization in the development of natural drugs or cosmetics to treat skin related diseases or infections.

scholarly journals Effect of repeated disinfections by microwave energy on the physical and mechanical properties of denture base acrylic resins

2009 ◽  
Vol 20 (2) ◽  
pp. 132-137 ◽  
Author(s):  
Rafael Leonardo Xediek Consani ◽  
Douglas Duenhas de Azevedo ◽  
Marcelo Ferraz Mesquita ◽  
Wilson Batista Mendes ◽  
Paulo César Saquy
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Flexural Strength ◽  
Physical And Mechanical Properties ◽  
Knoop Hardness ◽  
Microwave Energy ◽  
Bending Test ◽  
Denture Base ◽  
Acrylic Resins ◽  
The Impact

The present study evaluated the effect of repeated simulated microwave disinfection on physical and mechanical properties of Clássico, Onda-Cryl and QC-20 denture base acrylic resins. Aluminum patterns were included in metallic or plastic flasks with dental stone following the traditional packing method. The powder/liquid mixing ratio was established according to the manufacturer's instructions. After water-bath polymerization at 74ºC for 9 h, boiling water for 20 min or microwave energy at 900 W for 10 min, the specimens were deflasked after flask cooling and finished. Each specimen was immersed in 150 mL of distilled water and underwent 5 disinfection cycles in a microwave oven set at 650 W for 3 min. Non-disinfected and disinfected specimens were subjected to the following tets: Knoop hardness test was performed with 25 g load for 10 s, impact strength test was done using the Charpy system with 40 kpcm, and 3-point bending test (flexural strength) was performed at a crosshead speed of 0.5 mm/min until fracture. Data were analyzed statistically by ANOVA and Tukey's test (α= 0.05%). Repeated simulated microwave disinfections decreased the Knoop hardness of Clássico and Onda-Cryl resins and had no effect on the impact strength of QC-20. The flexural strength was similar for all tested resins.

scholarly journals Evaluation of the Effect of Propolis Nanoparticles on Antimicrobial Properties and Shear Bond Strength of Orthodontic Composite Bonded to Bovine Enamel

2019 ◽  
Author(s):  
Ahmad Sodagar ◽  
Azam Akhavan ◽  
Sepideh Arab ◽  
Abbas Bahador ◽  
Maryam Pourhajibagher ◽  
...  
Keyword(s):  
Bond Strength ◽  
Shear Bond Strength ◽  
Antimicrobial Property ◽  
Testing Machine ◽  
Antimicrobial Properties ◽  
Inhibition Zone ◽  
Colony Growth ◽  
Control Group ◽  
Growth Inhibition Zone ◽  
Bovine Enamel

We aimed to investigate the effects of propolis nanoparticles (prpNPs) on antimicrobial property and shear bond strength (SBS) of orthodontic composite bonded to bovine enamel. Materials and Methods: Sixty bovine teeth were randomly divided into five groups (n=12). PrpNPs were prepared at concentrations of 0% (control), 1%, 2%, 5%, and 10% in Transbond XT composite to bond stainless steel brackets to the teeth. SBS between brackets and teeth was measured using a universal testing machine. After debonding, the adhesive remnant index (ARI) on bracket bases was measured. In the microbial test, composites with the aforementioned concentrations of prpNPs were cured in metal discs. The bacteria included Streptococcus mutans (S. mutans), Streptococcus sanguinis (S. sanguinis), and Lactobacillus acidophilus (L. acidophilus), and antimicrobial effects of prpNPs were investigated by anti-biofilm, disc agar diffusion and eluted component tests. Results: The 10% prpNPs group showed the lowest SBS. Colony growths of S. mutans and S. sanguinis at all concentrations (except for 1%) was significantly lower than the control group. L. acidophilus colony growth was significantly reduced at 5% and 10% concentrations. Growth inhibition zone developed at 2%, 5%, and 10% concentrations for S. mutans and S. sanguinis. The lowest numbers of S. mutans and S. sanguinis colonies at all concentrations were observed on day 15. L. acidophilus colonies decreased significantly at all concentrations (except for 1%) until day 30.

scholarly journals TESTING OF THE FRACTURE RESISTANCE OF THE HEAT-CURING DENTURE BASE ACRYLIC RESIN

2018 ◽  
Vol 9 (2) ◽  
Author(s):  
Aleksandra Maletin ◽  
Jovana Bastajić ◽  
Ivan Ristić ◽  
Branislava Petronijević Šarčev ◽  
Isidora Nešković ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Fracture Resistance ◽  
Acrylic Resin ◽  
Denture Base ◽  
Universal Testing ◽  
Heat Curing ◽  
Significant Difference ◽  
Student’S T ◽  
Student’S T Test

For many years, poly-methyl methacrylate has been used as a material of choice for making the denture base, thanks to its good and desirable performances, such as: simplicity in work, possibility of reparation, aesthetics and affordable price. Considering to its insufficient hardness and fracture resistance, there is a tendency to improve the mechanical properties of the material, by changing its basic composition. The aim of the research was to determine the fracture resistance of the heat-curing denture base acrylic resin materials. Materials and methods: For the research ,20 samples of the 2 heat-curing acrylics had been prepared, standard ones and reinforced acrylic resin material. After the storage in the saline for 15 days, measurements of the fracture resistance were performed by using the universal testing device. The data were statistically processed using the Student’s t-test for independent samples. Results: By measuring the flexural strength and deflection at breakage, it has been proven that there was, statistically, a significant difference of the flexural strength between reinforced (179.91-248.72MPa) and standard heat-curing acrylics (183.25- 200.74MPa). The deflection at breakage showed approximately the same values for both materials (1,0-1,4mm; 1.0-1.5mm). Conclusion: By enhancing the polymer, the mechanical properties of the denture base acrylic resin materials will be improved, primarily, higher fracture resistance, that means that these technologies need to be improved.

scholarly journals Variations in Flexural Strength of Heat-polymerized Acrylic Resin after the Usage of Denture Cleansers

2016 ◽  
Vol 17 (4) ◽  
pp. 322-326 ◽  
Author(s):  
M Kalavathi ◽  
Mallikarjuna Ragher ◽  
G Vinayakumar ◽  
Sanketsopan Patil ◽  
Aishwarya Chatterjee ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Testing Machine ◽  
Peak Load ◽  
Acrylic Resin ◽  
Control Group ◽  
Denture Base ◽  
Acrylic Resins ◽  
Significant Difference ◽  
Base Resin ◽  
Denture Cleansers

ABSTRACT Objective The objective of this study was to evaluate and compare changes in the flexural strength of heat-cured denture base resins when treated using denture cleansers. Study design A total of 40 specimens with dimension 65 mm length, 10 mm width, and 3 mm thickness were prepared as per ISO 1567 specification. A total of 10 specimens were immersed in distilled water to be used as control. Of the remaining 30 samples, 10 were treated with Clinsodent, 10 with VI-Clean, and 10 with Clanden denture cleansers. Specimens in each group were subjected to three-point flexural load in universal testing machine at a cross-head speed of 5 mm/min. The peak load (N) was recorded and flexural strength was calculated. The findings were analyzed using Kruskal–Wallis analysis of variance and Mann–Whitney test. Results Heat-cured denture base resin selected for this study showed significant difference in flexural strength after immersion in denture cleansers Clinsodent, VI-Clean, and Clanden solutions, when compared with the control group. Conclusion Findings of this study showed that denture cleansers altered the flexural strength of heat polymerized acrylic resins that endured soaking cycles which simulated 180 days of use. Hence, denture cleansers should be used with caution, once a day after brushing the dentures. It is advisable for patients to follow the manufacturer's instructions. How to cite this article Ragher M, Vinayakumar G, Patil S, Chatterjee A, Mallikarjuna DM, Dandekeri S, Swetha V, Pradeep MR. Variations in Flexural Strength of Heat-polymerized Acrylic Resin after the Usage of Denture Cleansers. J Contemp Dent Pract 2016;17(4):322-326.

scholarly journals GC-MS Analysis of the Compositions and Antimicrobial Activities of Essential Oils From Five Species of Lamiaceae in Iran

2021 ◽  
Author(s):  
mansureh ghavam
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Essential Oils ◽  
Antimicrobial Properties ◽  
Inhibition Zone ◽  
Antimicrobial Activities ◽  
Gas Chromatography Mass Spectrometry ◽  
Probability Of Error ◽  
Chromatography Mass Spectrometry ◽  
Significant Difference

Abstract Essential oils (EOs) separated from Lamiaceae species attract more attention due to their abundant use in the preservation of natural foods and pharmaceutics and have gained considerable interester in research and industrial. The aim of this study was to evaluate composition and antimicrobial activity of EOs obtained from five species Lamiaceae in Iran. After extraction of EOs by Clevenger, their composition was evaluated by gas chromatography-mass spectrometry (GC–MS). Antimicrobial properties were assayed by measuring inhibition zones, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The results showed that the effects of species, on yield and predominant compounds amount of EOs of five species were significant with a probability of error of 1 %. The yield of oils were varied from ~ 0.02 to ~ 1.88%. About 66 components were identified by gas chromatography-mass spectrometry (GC-MS), and the dominant compounds were included thymol (67.71%), oleic acid (0.49–62.09%), (-)-caryophyllene oxide (0.41–24.81%), α-pinene (1.09–19.41%), 1,8-cineole (0.22–15.40%), palmitic acid (0.32–13.28%), (+)spathulenol (11.16%), and germacrene D (0.30-10.26%) in different species. The results of analysis of variance showed that there was a significant difference between the mean of the inhibition zone obtained treating the different microorganisms with the essential oil of five species (P ≤ 0.01). The highest inhibition zone belonged to TDEO (39.33 ± 0.58 and 25.00 ± 0.00 mm) against Gram-positive S. aureus and A. brasiliensis. The Gram-negative P. aeruginosa showed the lowest inhibitory resistance to HIEO, SIEO, and ROEO (with a MIC value of 31.25 µg/mL), which was very significant compared to rifampin. Therefore, EOs of five species have potential applications in the control of various bacteria and fungi and can be a natural alternative to some antibiotics.

scholarly journals ANTIMICROBIAL EFFECTS OF SOME DICOTYLEDONOUS PLANTS ON FUNGAL ISOLATES OF CANDIDA albicans AND TRICHOPHYTON mentagrophyte

2021 ◽  
Vol 4 (1) ◽  
pp. 1-4
Author(s):  
Obhioze Augustine Akpoka ◽  
A. A. Enaigbe ◽  
M. U. Okwu ◽  
O. E. Izevbuwa ◽  
E. A. Ufuah
Keyword(s):  
Candida Albicans ◽  
Antimicrobial Properties ◽  
Inhibition Zone ◽  
Antimicrobial Activities ◽  
Sensitivity Test ◽  
Diffusion Method ◽  
Leaf Extracts ◽  
Disk Diffusion Method ◽  
Fungal Isolates ◽  
Drug Concentrations

The preliminary phytochemical screening revealed that, antimicrobial properties of the leaf extracts were due to secondary metabolites such as amino acids, essential oils, flavonoids and saponins contained. The antimicrobial activities of alcoholic extracts were tested against pathogenic fungal isolates of Candida albicans and Trichophyton mentagrophyte. This was performed by inoculating the isolates into the pure extract, spread onto petri plates containing Sabouraud dextrose agar (SDA) media, observed for growth at stipulated standards. The sensitivity test was done by the disk diffusion method to test the effectiveness of an antimycotic (Griseofulvin) applied on the specific isolates. The minimum inhibitory concentration (MIC) was determined to ascertain the lowest drug concentrations that inhibited the fungal growths. The antimicrobial test revealed that, the leaf extracts of Eupatorium odoratum and Canjanus cajan inhibited the growths of the organisms while extracts of Citrus aurantifolia and Eucalyptus citriodora only prevented the growth of Candida albicans. The sensitivity test recorded the inhibition zone to range from 11 mm to 32 mm, with the lowest cleared area reported in the extract of E. citriodora and the highest in E, odoratum. Consequently, the MIC values of extracts at dilution levels were; E. odoratum: 1: 10000; 1: 1000, C. cajan: 1: 1000; 1: 10000, E. citriodora: 1:1000; 1:100 and C. aurantifolia: 1: 100000; 1: 100 respectively. This work has confirmed the progressive utilization of plants as antimicrobials for the benefit of mankind, to have originated from microbial sources.

scholarly journals Quaternary ammonium salt of chitosan: preparation and antimicrobial property for paper

Open Medicine ◽  
2015 ◽  
Vol 10 (1) ◽  
Author(s):  
Pengtao Liu ◽  
Weisheng Meng ◽  
Shuai Wang ◽  
Yonghui Sun ◽  
Muhammad Aqeel Ashraf
Keyword(s):  
Ammonium Chloride ◽  
Antimicrobial Property ◽  
Antimicrobial Properties ◽  
Inhibition Zone ◽  
Antimicrobial Activities ◽  
Inhibitory Effects ◽  
Zone Method ◽  
E Coli ◽  
H Nmr ◽  
Ft Ir

Abstract A series of 2-hydroxypropyltrimethyl ammonium chloride chitosan (HACC) was prepared by the reaction of chitosan with glycidyl trimethyl ammonium chloride. Structure of HACC was characterized by FT IR and 1H NMR spectroscopies, and it was proved that substitution reaction mainly occurs on the N element. Antimicrobial activities of HACC was examined against S. aureus, E. coli, and A. niger. Results indicatd that the inhibitory effects of HACC solutions were varied with HACC concentration, quaternization degrees, pH values, metal ions, and heat treatment. The antimicrobial properties of handsheets prepared from HACC were studied by the inhibition zone method, and the sheets had good antimicrobial properties against S. aureus and E. coli, and low inhibition rate against A. niger.

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