ABSTRACT
BACKGROUND: Titanium miniscrews are used at an ever-increasing rate to provide orthodontic anchorage. The aim of this study was to evaluate the mechanical performance of miniscrews after dry and steam sterilization. MATERIALS AND METHODS: In this experimental study, a total of 72 miniscrews from two different manufacturers with a diameter of 1.6 mm and height of 8 mm were divided into six groups (n = 12). One group of screws from each manufacturer was considered as the control group; the second underwent steam sterilization; and the last group was subjected to dry sterilization. Insertion and fracture torques of each miniscrew were assessed by a torque tester. Data were analyzed using the Kruskal-Wallis and Mann-Whitney tests (P < 0.05). RESULTS: For Jeil miniscrew, no statistically significant differences were detected between the steam-sterilized and control groups in their insertion torques (P > 0.05). There was a statistically significant difference between the steam sterilized, dry sterilized and control groups with respect to their fracture torque (P < 0.001). For Hubit miniscrew, there were no significant differences between steam sterilized, dry sterilized and control groups in their insertion torque (P > 0.05) and between steam sterilized and control groups with respect to their fracture torque (P > 0.05). There were significant differences in the mean values of insertion and fracture torques between the two different manufacturers (P < 0.001). CONCLUSION: Steam sterilization had no detrimental effects on torque values of miniscrews, but dry heat sterilization affected their mechanical properties.
ABSTRACT
Chitosan-coated magnetic nanoparticles are an appropriate drug delivery method which can improve the therapeutic properties of chemotherapy agents and also can be useful as MRI contrast agent for early cancer diagnosis. This research discovers the optimization of the possible therapeutic effects of Chitosan- citric acid- Fe3O4- CUR quartets. Chitosan as a natural polymer can use to encapsulate citric acid modified Fe3O4 nanoparticles. The successful preparation of CUR-loaded nano-carriers was confirmed by X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and transmission electron microscopy (TEM) techniques. Moreover, the hemolysis test was used for the study of hemobiocompatibility. The loading capacity and encapsulation efficiency of CUR molecules were 11±0.09% and 49.5±0.41%, respectively. The anticancer effect of the void of CUR and CUR-loaded nano-carriers were compared by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay on the treated MCF-7 cell lines. It can be concluded that the use of these nanoparticles are a better and more efficient approach for the controlled and slow release of CUR in the cancer treatment.
