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    Conversion degrees of resin composites using different light sources
    (2013) Ozturk B.; Cobanoglu N.; Cetin Dr. A.R.; Gunduz B.
    Objective: The objective of this study was to compare the conversion degree of six different composite materials (Filtek Z 250, Filtek P60, Spectrum TPH, Pertac II, Clearfil AP-X, and Clearfil Photo Posterior) using three different light sources (blue light-emitting diode [LED], plasma arc curing [PAC], and conventional halogen lamp [QTH]). Methods: Composites were placed in a 2 mm thick and 5 mm diameter Teflon molds and light cured from the top using three methods: LED for 40 s, PAC for 10 s, and QTH for 40 s. A Fourier Transform Infrared Spectroscopy (FTIR) was used to evaluate the degree of conversion (DC) (n=5). The results were analyzed with two-way analysis of variance and Tukey HSD test. Results: DC was significantly influenced by two variables, light source and composite (P<.05). QTH revealed significantly higher DC values than LED (P<.05). However, there were no significant differences between DC values of QTH and PAC or between DC values of LED and PAC (P>.05). The highest DC was observed in the Z 250 composite specimens following photopolymerization with QTH (70%). The lowest DC was observed in Clearfil Photo Posterior composite specimens following photo- polymerization with LED (43%). Conclusions: The DC was found to be changing according to both light sources and composite materials used. Conventional light halogen (QTH) from light sources and Filtek Z 250 and Filtek P 60 among composite materials showed the most DC performance.
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    The effect of intravitreal bevacizumab and ranibizumab on macular edema of the contralateral eye: A comparative study of two anti-VEGFs
    (Medknow Publications, 2016) Bakbak B.; Ozturk B.; Gonul S.; Gedik S.
    Purpose: To compare the effects of bevacizumab and ranibizumab on the visual function and macular thickness in the contralateral (untreated) eye of patients with bilateral diabetic macular edema (DME). Materials and Methods: Thirty-nine patients with bilateral DME, who had been treated with both bevacizumab and ranibizumab in the same eye, were considered retrospectively for this study. Recorded outcome measurements included the best-corrected visual acuity (BCVA) assessment with the Early Treatment Diabetic Retinopathy Study (ETDRS) chart and the central subfield macular thickness (CSMT) measurement of the contralateral, uninjected eye before and at 4 weeks after the injections. Results: The median BCVA of the uninjected eye was 50 ETDRS letters and the median CSMT was 459 ?m preceding the bevacizumab injection whereas at the control appointment, 4 weeks after the injection, the median BCVA had increased to 52 letters (P = 0.098), and the median CSMT had decreased to 390 ?m (P = 0.036). The mean interval between the bevacizumab and ranibizumab treatments was 4.79 1.52 months. The measurements of the untreated eye after the ranibizumab treatment showed that the median BCVA decreased from 55 to 52 letters, and the median CSMT increased from 361 ?m to 418 ?m (P = 0.148 and P = 0.109, respectively). Conclusions: In contrast to ranibizumab, the intravitreal administration of bevacizumab resulted in a statistically significant decrease in macular thickness in the untreated eye in patients with bilateral DME. © 2016 Oman Ophthalmic Society | Published by Wolters Kluwer Medknow.
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    The effects of exogenous estradiol and progesterone with melatonin on homocvsteine levels in ovariectomized rats
    (2007) Oztekin E.; Mogulkoc R.; Baltaci A.K.; Ozturk B.; Tiftik A.M.
    The study was carried out an 24 adult, Spraque-Dawfey strain of female rats. Group 1: Control group; Group 2: Ovariectomy group; Group 3 : supplemented with esradiol and progesterone after ovariectomy. Estradiol propionate 450?g/kg and medroxyprogesterone acetate 15mg/kg were supplemented a one time every week and melatonin injection (3mg/kg/rat) was made for four weeks. Serum homocysteine levels in groups 2 and 3 were significantly higher than those in groups 1 and 4. Homocysteine levels in groups 1 and 4 were not different from each other. The findings demonstrate that ovariectomy leads to a significant increase in homocysteine levels, but hormone (estradiol and progesterone) replacement could not prevent this increase. However, this increase was suppressed by exogenous melatonin supplementation.