Yazar "Önem E." seçeneğine göre listele
Listeleniyor 1 - 8 / 8
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Changes in the fractal dimension, feret diameter, and lacunarity of mandibular alveolar bone during initial healing of dental implants(2012) Önem E.; Güniz Baksı B.; Sogur E.Purpose: To evaluate the combination of fractal dimension (FD), lacunarity, and Feret diameter (FeD) to quantitatively characterize structural changes of mandibular alveolar bone around dental implants during initial healing. Materials and Methods: Three standard-sized regions of interest (ROIs) (mesial and distal crest and apical area) around implants and three ROIs of the same size in the alveolar bone on the contralateral side were analyzed on digital panoramic images. FD was calculated using the box-counting method, and lacunarity was calculated using the FracLac plugin of Image J software. FeD was measured in the same ROIs. Comparisons of the groups were done with the Dunnett test. Results: Forty-two implants in the posterior mandibles of 21 patients were used for FD measurements. A total of 189 ROIs was segmented into binary images. Mean FD values for mesial, distal, and apical ROIs around implants were 1.26, 1.36, and 1.4, respectively. The mean FD of alveolar bone around premolars/molars was 1.39 for all ROIs. The mean FeD for mesial, distal, and apical ROIs around implants was 7.63, 7.86, and 8.02, respectively, whereas it ranged between 7.88 and 8.13 for premolar teeth. Mean lacunarity values for mesial, distal, and apical ROIs around implants were 0.53, 0.51, and 0.48, respectively. Lacunarity values for ROIs around premolars ranged between 0.45 and 0.50. No significant differences were observed in FD, FeD, or lacunarity measurements between ROIs around implants and around teeth. Conclusions: The satisfactory healing of bone following implant placement may be monitored by calculating FD, lacunarity, and FeD using digital panoramic images. Although preliminary, these values may alert the practitioner to any implants with loss of stability. © 2012 by Quintessence Publishing Co Inc.Öğe Determination of thermal behavior of leathers in different processes by differential scanning calorimetry and evaluation of the analysis conditions [Farkli proses aşamasindaki' deri'leri'n di'feransi'yel taramali kalori'metre i'le termal davranişlarinin belirlenmesi ve anali'z koşullarinin değerlendirilmesi'](Chamber of Textile Engineers, 2018) Önem E.; Yorgancioğlu A.; Yilmaz O.; Karavana H.A.; Zengin G.; Bitlisli B.O.The study examined the thermal behavior of leathers in different processes by differential scanning calorimetry (DSC) under the various analysis conditions and the representativeness of hydrothermal stability of leathers by DSC method were investigated. For this purpose, hydrothermal stability of the raw skin, pickled, tanned and finished leathers was firstly analyzed with standard shrinkage temperature test. Then, same leather samples were analyzed in dry and wet states under the different conditioning parameters by DSC method. The obtained data showed that the leather samples analyzed between 25-150 °C, in aqueous media, conditioned for 24 h and within the anti-pressure cells provided the best results. Moreover, the data derived from DSC thermograms under the cited conditions were also parallel with the shrinkage temperature (Ts) values of leathers obtained by standard method. © 2012.Öğe Determination of thermal behavior of leathers in different processes by differential scanning calorimetry and evaluation of the analysis conditions [Farkli proses aşamasindaki? deri?leri?n di?feransi?yel taramali kalori?metre i?le termal davranişlarinin belirlenmesi ve anali?z koşullarinin değerlendirilmesi?](Chamber of Textile Engineers, 2018) Önem E.; Yorgancioğlu A.; Yilmaz O.; Karavana H.A.; Zengin G.; Bitlisli B.O.The study examined the thermal behavior of leathers in different processes by differential scanning calorimetry (DSC) under the various analysis conditions and the representativeness of hydrothermal stability of leathers by DSC method were investigated. For this purpose, hydrothermal stability of the raw skin, pickled, tanned and finished leathers was firstly analyzed with standard shrinkage temperature test. Then, same leather samples were analyzed in dry and wet states under the different conditioning parameters by DSC method. The obtained data showed that the leather samples analyzed between 25-150 °C, in aqueous media, conditioned for 24 h and within the anti-pressure cells provided the best results. Moreover, the data derived from DSC thermograms under the cited conditions were also parallel with the shrinkage temperature (Ts) values of leathers obtained by standard method. © 2012.Öğe Diagnostic accuracy of proximal enamel subsurface demineralization and its relationship with calcium loss and lesion depth(2012) Önem E.; Baksi B.G.; Şen B.H.; Sögüt Ö.; Mert A.Objective: The aim of this study was to determine the relationship between the amount of calcium loss, lesion depth, and the accuracy of storage phosphor plate (SPP) and film radiographs for the detection of artificial proximal demineralization. Methods: Standard enamel windows of extracted premolars were exposed to a demineralizing solution for 60 h, 80h, 100 h and 120 h. Solutions were analysed for calcium concentration by atomic absorption spectrometer and the lesion depths were calculated by a specific formula. All teeth were radiographed with SPPs and F-speed films before and after acid application. Images were evaluated by five observers. Stereomicroscopic and scanning electron microscopic (SEM) observations were carried out to visualize enamel surfaces after acid exposure. Receiver operating characteristic analysis was used for diagnostic accuracy (A z). A zs were compared with factorial analysis of variance and t-tests. The relationship between A zs and lesion depths was determined with Pearson's correlation test. Results: Strong positive correlation was found between A zs of both radiographic methods and lesion depths. No difference was found between the A zs of two radiographic systems for any of the demineralization durations (p > 0.05). Pair-wise comparisons revealed no significant difference in Azs of SPPs (p > 0.05), while significant differences were obtained for the A zs of films for different demineralization periods (p < 0.05). Stereomicroscopic and SEM observations confirmed demineralizations from superficial to deeper layers of enamel. Conclusion: Subsurface enamel demineralization was not accurately detectable with either storage phosphor plates or F-speed films. The amount of calcium loss and the depth of demineralization have a strong relationship with diagnostic accuracy with a significant effect particularly on F-speed films. © 2012 The British Institute of Radiology.Öğe Effect of different atmospheric conditions on some physical properties of leather(2011) Başaran B.; Bitlisli B.O.; Ocak B.; Önem E.In this study, the effect of conditioning under standard and tropical atmospheric conditions on physical properties of leather was investigated. For this purpose, garment sheep leathers were conditioned under standard atmospheric conditions of 23 °C ± 2 °C temperature and % 50 ± relative humidity suggested in TS EN ISO 2419, and under tropical atmospheric conditions of 27 °C ± 2 °C temperature and % 65 ± 5 relative humidity suggested in ISO/DIS 2419. Then, changes in leather physical properties were investigated statistically. According to results, for sheep leather conditioned under standard atmospheric conditions, percentage extension was 53.47 ± 4.10, Young's modulus was 77.32 ± 23.34 N/mm, double edge tear load was 38.03 ± 8.47 N, water vapour permeability was 6.18 ± 0.55 mg/cm2.h, while under tropical atmospheric conditions, percentage extension was 57.67 ± 5.36, Young's modulus was 69.42 ± 13.87 N/mm, double edge tear load was 43.06 ± 10.50 N, water vapour permeability was 6.61 ± 0.47 mg/cm2.h. The difference between these physical properties was determined to be statistically significant. Changes in tensile strength and single edge tear load were not significant.Öğe Effect of exposure parameters on the radiopacity of root canal sealers(2013) Önem E.; Baksi B.G.; Şen B.H.Background: The aim of this study was to test the effect of different kilovoltage, milliampere, and exposure time settings on the radiopacity of two endodontic sealers using an image plate system. Materials and methods: MM-Seal (MicroMega, Besancon, France) and Diaket (3M Espe, Seefeld, Germany) were packed into a polytetrafluoroethylene ring mold with an internal diameter of 10. mm and a depth of 1. mm. Five discs of each material were imaged alongside an aluminum step-wedge. Sets of radiographs were obtained using storage phosphor plates (SPPs). The SPPs were exposed at 60, 65, or 70. kVp, 7 or 8. mA for 0.12 or 0.16. s. Radiographic densities of the sealers and each step of the step-wedge were analyzed with Image Tool 3.0 SDK software (University of Texas Health Sciences Center, TX, USA). Three readings were made for each image. The mean was calculated to give the radiographic density expressed as mean gray values. Three-way ANOVA was used to test the differences in radiopacity of sealers with respect to kilovoltage, milliampere, exposure time, and the interaction of the three factors. Results: No significant difference in sealers' radiopacity was found with change in three exposure parameters (p>. 0.05). However, standard deviations of the measurements for lower exposures were greater; MM-Seal was significantly more radiopaque than Diaket (p<. 0.0001) at any parameter. Conclusions: Differences in kilovoltage, milliampere, and exposure time do not affect the radiopacity measurements of sealers on SPP images. However, choosing the proper exposure parameters may optimize the gray value range of the sealers allowing for better discrimination of the sealer and surrounding structures thereby providing better clinical guidance. © 2012 Japanese Stomatological Society.Öğe Factors of patient satisfaction/ dissatisfaction in a dental faculty outpatient clinic in Turkey(Blackwell Munksgaard, 2000) Gürdal P.; Çankaya H.; Önem E.; Dinçer S.; Yilmaz T.Being service providers, dental professionals should satisfy their consumers/dental patients. This study investigates satisfaction with dental care among the patients of a dental faculty outpatient clinic of a major university in İzmir, Turkey. Method: The study was performed on 1001 patients of whom 674 filled out the questionnaire containing sociodemographic items and open-ended questions to determine the factors of (dis)satisfaction. The open-ended questions were content analyzed, and each patient was scored according to his comments: "complaining: (0)", "both praising and complaining: (1)", "no comment: (2)", and "praising: (3)". Each factor that has an impact on the decision of the study sample was determined by statistical analyses of data, using student t-test, chi-square test, and multiple regression analysis. Results: Most of the patients were highly educated (74.7%), had a high income (48.7%), and were young to middle-aged (73.1%). There was a well-balanced gender representation. The patient sample had sought care mostly for dental caries, periodontal diseases, problems with old restorations, and prosthetic rehabilitation. Of 1001 patients, 38.6% were satisfied with the dental care they received, 23.8% were both satisfied and dissatisfied, 5% were dissatisfied, and 32.7% failed to comment. No significant differences were observed between the satisfaction/dissatisfaction scores and sociodemographic variables of the patients in the groups (P>0.05). The most important components of satisfaction were found to be "relationship between dentists and patients" (P<0.001), "organized service system" (P<0.001), and "scientific ability of dental personnel" (P<0.001). The most prominent complaints were "long treatment span" (P<0.001), "disorganized service system" (P<0.001), and "slowness of radiographical examination procedures" (P<0.001). Conclusions: Despite the significant variations among the cultural and ethnic structures of different societies, personal interactions have priority in establishing satisfying dental service.Öğe Investigation on the effects of various waste extracts on free formaldehyde in leather(2011) Eke Bayramoglu E.; Önem E.; Yorgancioglu A.; Yilmaz B.Due to the some chemical substances used in leather manufacturing, free formaldehyde is released in finished leathers and made serious problems for tanners. This situation causes the firms not to get Eco-Leather label and great problems are experienced about leather sales especially in recent years because natural and ecological products are in fashion. This study aims to reduce the free formaldehyde amount in leather by using various plant extracts (hazelnut shells, thyme, olive shoots, lavandula, ivy, christ's thorn seed), which are obtained from agricultural wastes, during retanning stage of leather processing. The analyses have been conducted with HPLC device according to IUC 19 (ISO TS 17226) method. According to the results; the extracts from hazelnut shells, thyme and olive shoots reduced the free formaldehyde amount on the leather by 35.49%, 33.86%, and 24.03% respectively. Color measurements on all finished leathers have been conducted with Konica Minolta CM-3600d brand spectrophotometer, light fastness analyses with ATLAS-XENOTEST ALPHA+ test instrument and according to ISO 105-B02 standard's method. The results showed that the plant extracts impacting formaldehyde considerably also improved the light fastness of the leather samples for a certain extent.
