1.Mechanical properties of zirconia after different surface treatments and repeated firings.
Meryem Gulce SUBASI ; Necla DEMIR ; Ozlem KARA ; A Nilgun OZTURK ; Faruk OZEL
The Journal of Advanced Prosthodontics 2014;6(6):462-467
PURPOSE: This study investigated the influence of surface conditioning procedures and repeated firings on monoclinic content and strength of zirconia before cementation. MATERIALS AND METHODS: Sintered bar-shaped zirconia specimens were subjected to no surface treatment (control), air abrasion, or grinding (n=21). Their roughness was evaluated using a profilometer, and microscope analysis was performed on one specimen of each group. Then, 2 or 10 repeated firings (n=10) were executed, the monoclinic content of specimens was analyzed by X-ray diffraction, and a three-point flexural strength test was performed. Surface roughness values were compared using one-way analysis of variance (ANOVA) and Tukey honestly significant difference (HSD) tests, the monoclinic content values were tested using Kruskal-Wallis and Mann-Whitney U tests, and the flexural strength values were tested using two-way ANOVA and Tukey HSD tests (P=.05). Spearman's correlation test was performed to define relationships among measured parameters. RESULTS: Surface-treated specimens were rougher than untreated specimens and had a higher monoclinic content (P<.005), and the relationship between roughness and monoclinic content was significant (P<.000). Neither surface treatment nor firing significantly affected the flexural strength, but Weibull analysis showed that for the air-abraded samples the characteristic strength was significantly lower after the 10th firing than after the 2nd firing. CONCLUSION: After firing, a negligible amount of monoclinic content remained on the zirconia surfaces, and rougher surfaces had higher monoclinic contents than untreated surfaces. Multiple firings could be performed if necessary, but the fracture probability could increase after multiple firings for rougher surfaces.
Cementation
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Ceramics
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Fires*
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X-Ray Diffraction
2. Antiprotozoal assessment and phenolic acid profiling of five Fumaria (fumitory) species
Ilkay Erdogan ORHAN ; Bilge SENER ; Nilgun OZTURK
Asian Pacific Journal of Tropical Medicine 2015;8(4):283-286
Objective: To explore some Fumaria species which were recorded to be traditionally used against malaria and other protozoal diseases. Methods: Consequently, in the current study, antiprotozoal effect of the ethanol extracts obtained from five Fumaria species (Fumaria densiflora, Fumaria cilicica, Fumaria rostellata, Fumaria kralikii, and Fumaria parviflora) was investigated against the parasites; Plasmodium falciparum (malaria) and Trypanosoma bruceirhodesiense (human African trypanosomiasis) at 0.81 and 4.85 μg/mL concentrations. Results: Among them, Fumaria densiflora extract exerted the highest antiplasmodial (93.80%) and antitrypanasomal effect (55.40%), while the ethanol extracts of Fumaria kralikii (43.45%) and Fumaria rostellata (41.65%) showed moderate activity against Plasmodium falciparum. Besides, phenolic acid contents of the extracts were analyzed using high performance liquid chromatography (HPLC) and trans-cinnamic (4.32 mg/g) and caffeic (3.71 mg/g) acids were found to be the dominant phenolic acids in Fumaria densiflora. Conclusions: According to our results, Fumaria densiflora deserve further study for its promising antiprotozoal activity.