Background: Thymus species are well-known as medicinal plants. It was aimed to investigate the chemical composition of Thymus pectinatus (TP) and its antioxidant, antimicrobial, antispasmodic, and angiogenic activities. Materials and Methods: After essential oil of TP (EO-TP) was obtained with clevenger distillation system, it was analyzed for chemical composition with GC-MS. To study antispasmodic activity, eight male Wistar albino rats each weighing approximately 250-300 g were used. Results: The results of the analysis revealed 19 components, which equals to 92.93 of the essential oil. The following are the main components; thymol (48.77%), m-cymene (9.15%), isoborneol (5.19%), trans-caryophyllene (4.43%), carvacrol (3.91%) and -terpinene (3.54%). It has been found that microorganisms subjected to whole all of microbiological tests are highly resistant to EO-TP. 2,2- diphenyl-l-picrylhydrazyl, hydroxyl radical, along with superoxide radical scavenging, and lipid peroxidation says were utilized to show the antioxidant activities of the EO-TP. In measuring its effect, 0.1 mg/mL and 0.5 mg/mL dosage of the EO-TP was applied to the rat ileum as a result of which the magnitude and the frequency of the contractions were observed to be significantly. Conclusion: It was also understood that EO-TP had angiogenic effect upon the vein system of the embryos of chicks. There is a need for further studies to clarify the mechanisms of antimicrobial, antioxidant and angiogenic effects and to determine the constituents of EO-TP responsible from these effects, especially the angiogenic.
This study aimed to compare the monomer elution, microhardness, and roughness of experimental resin-based composites (RBCs) prepared from a novel monomer system derived from 9,9-Bis[4-(2-hydroxyethoxy)phenyl]fluorene) (Bis-EFMA), bisphenol A-glycidyl methacrylate (Bis-GMA), and urethane dimethacrylate (UDMA) with each other, also with a commercial RBC, 3 M ESPE FiltekTM Z250 (FZ). Experimental Bis-EFMA (ET), Bis-GMA (BT), and UDMA (UT) based composites were prepared (20% Bis-EFMA or 20% Bis-GMA or 20% UDMA, and 20% triethylene glycol dimethacrylate [TEGDMA], and 60% glass filler). 60 specimens were produced (n = 5) and exposed to ethanol solution for 7 days. Then specimens were tested at baseline (T0), first (T1), third (T2), and seventh (T3) days. ET and FZ released significantly lower TEGDMA than other RBCs did (p < 0.05). BT released significantly higher TEGDMA than other RBCs did at T1 (p < 0.05). However, no significant difference was found between FZ and ET at T1 (p > 0.05). FZ exhibited the highest microhardness at all-time points; besides, the microhardness of BT was lowest at T0, while the microhardness of BT and UT was lower than that of FZ and ET at T1, T2, and T3 (p < 0.05). BT exhibited higher roughness at T2 than the UT did at T0 and T1, significantly (p < 0.05). However, no significant difference was found between the other RBCs (p > 0.05). Bis-EFMA, a novel bisphenol A-free monomer system, has the potential to be used in commercial RBCs as a substitute for Bis-GMA in terms of lower monomer elution and higher microhardness.
In prosthodontics, to increase the bonding of metals with porcelain by several means including laser surface treatments is still an important research topic. The current study was undertaken to evaluate the influence of surface treatment with Ho:YAG, Er:YAG, and Nd:YAG lasers on the shear bond strength (SBS) of low fusion dental porcelain to titanium and zirconium oxide substructures. Titanium (n=70) and zirconium oxide (n=70) specimens were categorized into 7 study groups (n=10): sandblasting, Er:YAG 1.5W and 2.5W, Nd:YAG 1.5W and 2.5W, and Ho:YAG 4W and 10W. Their surface morphology was examined with under scanning electron microscopy (SEM) after surface treatment. After application of low fusion dental porcelain, the SBS test was performed applying a universal testing machine. In the titanium specimens, the SBSs of the Nd:YAG laser 2.5W and 1.5W were significantly higher than those of the sandblasting and other lasers, respectively (p<0.05); In the zirconium oxide specimens, the SBSs of the sandblasting, Nd:YAG 1.5W and Nd:YAG 2.5W lasers were significantly higher than those of the other lasers, respectively (p<0.05); In the titanium specimens, Er:YAG 1.5W, Nd:YAG 2.5W, and Ho:YAG 10W lasers provided significantly higher SBSs compared to those in the zirconium oxide specimens (p<0.05). To increase SBS of low fusion porcelain with titanium and zirconium oxide substructures, Nd:YAG laser is more successful compared to Er:YAG and Ho:YAG lasers. The laser applications provide different SBS results although there are no obvious differences among their surfaces by SEM; this requires further research in order to clarify the mechanism of these differences.
In current experimental settings, Er:YAG laser applied to DLS infrastructure veneered with Vita porcelain increases bonding strength more distinctly, and Nd:YAG laser applied to Ni-Cr-based infrastructure veneered with G-Ceram porcelain alters bonding strength unfavorably.
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