AIM: With the increased bacterial resistance and the resulting problems in recent years, it seems necessary to find new biocompatible compounds to confront this problem. This research was conducted to optimise the synthesis of cobalt oxide nanoparticles with the highest antibacterial activity. METHODS: In the present study, 9 experiments were designed using the Taguchi method. The effect of three factors of cobalt nitrate, KOH and the stirring time in the synthesis of cobalt oxide nanoparticles with the highest antibacterial activity was investigated. The bactericidal effect of synthesised nanoparticles was evaluated using the colony-forming unit (CFU) and disk diffusion methods. The characteristics of nanoparticles were studied using the Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and the scanning electron microscopy (SEM). RESULTS: The results indicated that all three evaluated factors were effective on the antibacterial properties of the synthesised nanoparticles. The best antibacterial activity of cobalt oxide nanoparticles was observed in experiment 9 (cobalt nitrate 0.6 M, KOH 2M and stirring time 60 min). The study of nanoparticles synthesised by FTIR, XRD, and SEM confirmed the formation of cobalt oxide nanoparticles with size (24 nm) and a proper structure (spinel structure). CONCLUSION: Due to the optimal antibacterial properties of the synthesised cobalt oxide nanoparticles, they can be used in the fabrication of dental and medical equipment with antibacterial properties.
Introduction. One of the main steps of impression is the selection and preparation of an appropriate tray. Hence, the present study aimed to analyze and compare the accuracy of one- and two-stage impression techniques. Materials and Methods. A resin laboratory-made model, as the first molar, was prepared by standard method for full crowns with processed preparation finish line of 1 mm depth and convergence angle of 3-4°. Impression was made 20 times with one-stage technique and 20 times with two-stage technique using an appropriate tray. To measure the marginal gap, the distance between the restoration margin and preparation finish line of plaster dies was vertically determined in mid mesial, distal, buccal, and lingual (MDBL) regions by a stereomicroscope using a standard method. Results. The results of independent test showed that the mean value of the marginal gap obtained by one-stage impression technique was higher than that of two-stage impression technique. Further, there was no significant difference between one- and two-stage impression techniques in mid buccal region, but a significant difference was reported between the two impression techniques in MDL regions and in general. Conclusion. The findings of the present study indicated higher accuracy for two-stage impression technique than for the one-stage impression technique.
In this study, optimal conditions to form cellulose-MgO nanocomposite with antibacterial properties were evaluated. Applying the Taguchi method, 9 experiments were designed and the effects of different concentrations of biopolymers cellulose (0.5, 1 and 2 mg/ml), MgO nanoparticles (2, 4 and 8 mg/ml) and stirring times (30, 60 and 90 min) on antibacterial activity of synthesized nanocomposites were assessed. The characterizations of products were investigated by dynamic light scattering (DLS), raman spectroscopy, scanning electron microscope (SEM), thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The results showed that the nanocomposite produced in the conditions of experiment 9 (MgO 8 mg/ml, cellulose 2 mg/ml and stirring time of 60 min) has the strongest antibacterial activity. The outcomes of both methods of colony forming units (CFU) and disc diffusion indicated that the antibacterial activity of cellulose-MgO nanocomposite was signifi cantly higher than its components (P <0.05). Thermal analysis indicated improvement in the thermal stability of the cellulose biopolymer after the formation of the nanocomposite. Due to the improvement of the antibacterial properties of cellulose-MgO nanocomposite compared to its components, we can use it as a new antibacterial agent in the fi elds of pharmaceutical, medicine and dentistry.
Background and Objectives: Interferon-gamma (IFN-γ)/interleukin-4 (IL-4) ratio may indicate a change in the immune response with a potential pathological effect presented in oral lichen planus (OLP) patients. Herein, this meta-analysis evaluated the role of serum and salivary interferon-gamma/interleukin-4 ratio in the severity and development of OLP. Materials and Methods: The Scopus, Cochrane Library, PubMed, and Web of Science databases were systematically searched to retrieve the relevant studies published up from the database inception to March 2019. The crude mean difference (MD) and 95% confidence interval (CI) were calculated by RevMan 5.3 software using a random-effects model. A sensitivity analysis was performed on the results using the CMA 2.0 software. A total of 98 studies were retrieved from the databases, of which at last seven studies were included in this meta-analysis. Results: The findings showed that the pooled MDs of serum and salivary IFN-γ/IL-4 ratio were −0.22 (95% CI: −1.16, 0.72; p = 0.64) and 0.17 (95% CI: −1.50, 1.84; p = 0.84) in OLP patients compared to controls, respectively. In addition, the pooled MDs of serum and salivary IFN-γ/IL-4 ratio were −0.15 (95% CI: −0.53, 0.23; p = 0.43) and −0.39 (95% CI: −0.63, −0.15; p = 0.001) in patients with erythematous/ulcerative subtype compared to patients with reticular subtype, respectively. Conclusions: In conclusion, the results of meta-analysis demonstrated that serum and salivary IFN-γ/IL-4 ratio cannot play a major role in OLP development and severity.
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