33 research outputs found
Geçmişten bugüne yüz protez materyalleri
No full textThis review described the evaluation facial prosthetics and explained the facial prosthetic materials. Nowadays, this increased success is related to the evaluation of the materials. ÖZET Bu çalışmada yüz protezlerinin tarihsel gelişimine kısaca değinilmiş ve geçmişten günümüze kadar kullanılan yüz protez materyalleri açıklanmıştır. Bugün ulaşılan başarı, bu materyallerdeki gelişime bağlıdır. Anahtar Kelimeler: Yüz protez materyalleri, silikon elastomer, poliüretan
İki farklı Co-Cr HBP alaşımının mekanik özelliklerinin karşılaştırılması
No full text<p><strong>Purpose:</strong> The purpose of this study was to compare the mechanical properties of two different removable partial denture alloys that are commonly used in Çukurova University Faculty of Dentistry.</p> <p><strong>Material and Methods:</strong> Using two different Co-Cr alloys; Magnum H60 (MESA, Travagliato, Italy) and Biosil F (Degussa Dental, GmbH, Hanau, Germany) ten tensile test specimens were prepared for each group according to the ADA specification number 14. Specimens were loaded to crack. Ultimate tensile strength and percent elongation of two groups were compared using Mann Whitney U test (α=0.05). Crack surfaces were investigated using a stereomicroskop.</p> <p><strong>Results:</strong> A statistically significant difference was found between ultimate tensile strength of Magnum H60 (828 ± 17.3 MPa) and Biosil F (782 ± 51.6) (α =0.01). Percent elongation of Magnum H60 and Biosil F were found as 6.77 ± 1.62 and 6.32 ± 2.38, respectively. No significant difference was found among the two groups when the percent elongation was compared (α =0.496). Stereomicroscope images that are taken from the crack surfaces of both groups show similarities. Porotic structures and cracks that formed during solidification of the alloys can be seen on crack surfaces.</p> <p><strong>Conclusion:</strong> Both of the Co-Cr removable partial denture alloys tested in the current study seem capable of serving in the mouth for a long time.</p> <p><strong> </strong></p> <p><strong>ÖZET</strong></p> <p><strong>Amaç:</strong> Bu çalışmanın amacı Çukurova Üniversitesi Diş Hekimliği Fakültesi’nde sıklıkla kullanılmakta olan iki farklı hareketli bölümlü protez alaşımının mekanik özelliklerini karşılaştırmaktır.</p> <p><strong>Gereç ve Yöntem:</strong> Magnum H60 (MESA, Travagliato, İtalya) ve Biosil F (Degussa Dental, GmbH, Hanau, Almanya) olmak üzere iki farklı Co-Cr alaşımı kullanılarak her grup için 10 örnek olmak üzere ADA’nın 14 nolu şartnamesine göre çekme testi örnekleri hazırlanmıştır. Örnekler kırılana kadar devam ettirilen çekme testinde iki grubun maksimum çekme dayanıklılığı ve uzama yüzdesi değerleri Mann Whitney U testi kullanılarak karşılaştırılmıştır (α=0.05). Kırılma yüzeyleri stereomikroskop kullanılarak incelenmiştir.</p> <p><strong>Bulgular:</strong> Magnum H60 grubunun maksimum çekme dayanıklılığının (828 ± 17.3 MPa) Biosil F’nin dayanıklılığından (782 ± 51.6) istatistiksel açıdan anlamlı ölçüde yüksek olduğu</p> <p>bulunmuştur (α =0.01). Magnum H60 ve Biosil F gruplarının uzama yüzdeleri sırası ile 6.77 ± 1.62 ve 6.32 ± 2.38 olarak bulunmuştur. İki grubun uzama yüzdeleri arasında anlamlı bir farklılık bulunamamıştır (α =0.496). Kırılma yüzeylerinden alınan stereomikroskop görüntüleri benzerlik göstermektedir. Her iki gruba ait örneklerin kırılma yüzeyinde alaşımın sertleşmesi sırasında oluşmuş porotik yapılar ve çatlaklar izlenmektedir.</p> <p><strong>Sonuç:</strong> Bu çalışmada test edilen Co-Cr alaşımlarının her ikisi de mekanik özellikleri açısından hareketli bölümlü protezlerin ağızda uzun süre kullanımı için uygundur.</p> <strong>Anahtar Kelimeler:</strong> Hareketli bölümlü protezler, Co-Cr alaşımları, maksimum çekme dayanımı, uzama yüzdes
İki farklı Co-Cr HBP alaşımının mekanik özelliklerinin karşılaştırılması
No full textPurpose: The purpose of this study was to compare the mechanical properties of two different removable partial denture alloys that are commonly used in Çukurova University Faculty of Dentistry. Material and Methods: Using two different Co-Cr alloys; Magnum H60 (MESA, Travagliato, Italy) and Biosil F (Degussa Dental, GmbH, Hanau, Germany) ten tensile test specimens were prepared for each group according to the ADA specification number 14. Specimens were loaded to crack. Ultimate tensile strength and percent elongation of two groups were compared using Mann Whitney U test (α=0.05). Crack surfaces were investigated using a stereomicroskop. Results: A statistically significant difference was found between ultimate tensile strength of Magnum H60 (828 ± 17.3 MPa) and Biosil F (782 ± 51.6) (α =0.01). Percent elongation of Magnum H60 and Biosil F were found as 6.77 ± 1.62 and 6.32 ± 2.38, respectively. No significant difference was found among the two groups when the percent elongation was compared (α =0.496). Stereomicroscope images that are taken from the crack surfaces of both groups show similarities. Porotic structures and cracks that formed during solidification of the alloys can be seen on crack surfaces. Conclusion: Both of the Co-Cr removable partial denture alloys tested in the current study seem capable of serving in the mouth for a long time. ÖZET Amaç: Bu çalışmanın amacı Çukurova Üniversitesi Diş Hekimliği Fakültesi’nde sıklıkla kullanılmakta olan iki farklı hareketli bölümlü protez alaşımının mekanik özelliklerini karşılaştırmaktır. Gereç ve Yöntem: Magnum H60 (MESA, Travagliato, İtalya) ve Biosil F (Degussa Dental, GmbH, Hanau, Almanya) olmak üzere iki farklı Co-Cr alaşımı kullanılarak her grup için 10 örnek olmak üzere ADA’nın 14 nolu şartnamesine göre çekme testi örnekleri hazırlanmıştır. Örnekler kırılana kadar devam ettirilen çekme testinde iki grubun maksimum çekme dayanıklılığı ve uzama yüzdesi değerleri Mann Whitney U testi kullanılarak karşılaştırılmıştır (α=0.05). Kırılma yüzeyleri stereomikroskop kullanılarak incelenmiştir. Bulgular: Magnum H60 grubunun maksimum çekme dayanıklılığının (828 ± 17.3 MPa) Biosil F’nin dayanıklılığından (782 ± 51.6) istatistiksel açıdan anlamlı ölçüde yüksek olduğu bulunmuştur (α =0.01). Magnum H60 ve Biosil F gruplarının uzama yüzdeleri sırası ile 6.77 ± 1.62 ve 6.32 ± 2.38 olarak bulunmuştur. İki grubun uzama yüzdeleri arasında anlamlı bir farklılık bulunamamıştır (α =0.496). Kırılma yüzeylerinden alınan stereomikroskop görüntüleri benzerlik göstermektedir. Her iki gruba ait örneklerin kırılma yüzeyinde alaşımın sertleşmesi sırasında oluşmuş porotik yapılar ve çatlaklar izlenmektedir. Sonuç: Bu çalışmada test edilen Co-Cr alaşımlarının her ikisi de mekanik özellikleri açısından hareketli bölümlü protezlerin ağızda uzun süre kullanımı için uygundur. Anahtar Kelimeler: Hareketli bölümlü protezler, Co-Cr alaşımları, maksimum çekme dayanımı, uzama yüzdes
Geçmişten bugüne yüz protez materyalleri
No full text<p>This review described the evaluation facial prosthetics and explained the facial prosthetic materials. Nowadays, this increased success is related to the evaluation of the materials.</p> <p> </p> <p><strong>ÖZET</strong></p> <p>Bu çalışmada yüz protezlerinin tarihsel gelişimine kısaca değinilmiş ve geçmişten günümüze kadar kullanılan yüz protez materyalleri açıklanmıştır. Bugün ulaşılan başarı, bu materyallerdeki gelişime bağlıdır.</p> <p><strong>Anahtar Kelimeler:</strong> Yüz protez materyalleri, silikon elastomer, poliüretan,</p>
Histomorphometric evaluation of implants coated with enamel or dentine derived fluoride-substituted apatite
No full textObjectives The aim of this study was to compare osseous healing characteristics of titanium implants coated with enamel-derived fluoride-substituted apatite (EFSA) or dentin-derived fluoride-substituted apatite (DFSA). Methods Fluoride-substituted apatite was derived from extracted human teeth with calcination method at 850 degrees C. DFSA and EFSA were separated and carefully ground with a blade grinder. Twenty-four titanium implants were prepared from a 99.99% pure titanium bar. EFSA and DFSA powders were sprayed separately on implants. As control group, unsprayed and sandblasted pure titanium implants were used. Eight adult rams were used in the study. One EFSA coated, 1 DFSA coated and 1 control implants were placed into right tibia of each rams. The rams were sacrificed after 6 months of healing. Undecalcified sections were prepared according to Donath's method and histomorphometric evaluation of implants was made. Results The mean bone contact percentage of DFSA-coated, EFSA-coated and control implants was 89.88% +/- 2.34, 70.19% +/- 13.11 and 53.12% +/- 5.76 respectively. This study suggests that DFSA-coated implants achieved better bone contact than EFSA-coated implants (P < 0.05). Also study groups presented better bone contact than control group (P < 0.05). Conclusions The results of this study show that although DFSA-coated implants achieved better bone contact, both DFSA and EFSA can be considered as appropriate coating materials
Effect of Thixotropic Agent on the Color Stability of Platinum-Based Silicone Maxillofacial Elastomers after Artificial Aging
No full textMaxillofacial prostheses are essential for restoring natural appearance and function in individuals with defects in the head and neck regions. Thixotropic agents, as liquid additives, are known to increase the viscosity of silicone elastomers. However, color deterioration remains a challenge in facial prostheses, leading to the need for refabrication. Despite this, there is limited research on the effect of thixotropic agents on the color stability of silicone maxillofacial elastomers. This study aims to investigate the impact of different thixotropic agent amounts on the color degradation of various maxillofacial silicone elastomers. Three elastomers (A-2000, A-2006, and A-2186) were combined with five pigments (no pigment as control, red, yellow, blue, and a mixture of red, yellow, and blue), and mixed with six thixotropic agent quantities (0, 1, 2, 3, 4, and 5 drops). A total of 450 specimens were fabricated (n = 5) and aged in an artificial aging chamber. L*, a*, b* readings were obtained before and after aging using a digital spectrophotometer. Color difference (ΔE*) means and standard deviations for 150 kj/m2, 300 kj/m2, and 450 kj/m2 were calculated. Statistical analyses, including four-way ANOVA and Fisher’s PLSD test, were conducted to determine any significant differences (p < 0.05) among the groups. A comprehensive analysis revealed significant four-way interactions among the groups. In the mixed-pigmentation group, adding 4 drops of thixotropic agent resulted in ΔE* above 3 only in A-2186 silicone at 300 and 450 kj/m2 energy levels. However, the color stability of mixed-pigmented A-2000 and A-2006 remained within the acceptable thresholds of 3 ΔE* at all irradiance levels in this study. At each energy level, A-2006 exhibited the highest color stability with an increasing thixotropic agent quantity among all the silicones. Conversely, A-2186 was more affected by the increased number of thixotropic agent drops in each pigmentation group, including the control group at 450 kj/m2. The quantity of thixotropic agent plays a crucial role in determining the color stability of different silicone elastomers pigmented with various intrinsic pigments. The thixotropic agent amount has a more significant impact on color stability than the type of pigment used in the silicone elastomers. A key overarching insight from this investigation is the identification of a safety threshold for the thixotropic agent quantity of 3 drops for each silicone type, pigmentation, and energy level. These findings highlight the importance of considering the proper combination of thixotropic agents, pigments, and silicone materials to achieve optimal color stability in maxillofacial prosthetic applications
Influence of Layer Thickness on Stress Distribution in Ceramic-Cement-Dentin Multilayer Systems
No full textWOS: 000260087100018PubMed ID: 18833778The effects of dentin and cement thicknesses on stress level and distribution of crack propagation in multilayer complex were analyzed. Custom-designed finite element analysis program based on JL Analyzer was used to analyze the stress distribution and present the maximum principal stress locations. In Zirconia, all the maximum stress values were above 100 MPa. In Empress II, they ranged between 50 and 105 MPa, which were approximately one-third of those of Zirconia. In Feldspathic, the maximum stress values were generally lower than 50 MPa. In all groups with 30 mu m cement thickness, the highest values were observed at the bottom surface. For cement thicknesses at 50, 70, and 100 mu m, maximum stress was found to occur at the top surface. However, changes in dentin thickness did not bring about significant changes in maximum stress values. Results of this study revealed the roles played by the following variables in the failure of a multilayer structure: cement thickness had a Minor influence, dentin thickness exerted no influence, but the thickness and type of ceramic system played a significant role
Konik Hüzmeli Bilgisayarlı Tomografiden Elde Edilen Kemik Densitesi Değeri Hemen Yüklenen İmplantların Stabilite Değişiklikleri Hakkında Öngörülebilir Bilgi Verir Mi?Bir Yıllık Rezonans Frekansı Takip Çalışması
No full textCross-frequency training with adversarial learning for radar micro-Doppler signature classification
No full textDeep neural networks have become increasingly popular in radar micro-Doppler classification; yet, a key challenge, which has limited potential gains, is the lack of large amounts of measured data that can facilitate the design of deeper networks with greater robustness and performance. Several approaches have been proposed in the literature to address this problem, such as unsupervised pre-training and transfer learning from optical imagery or synthetic RF data. This work investigates an alternative approach to training which involves exploitation of “datasets of opportunity” - micro-Doppler datasets collected using other RF sensors, which may be of a different frequency, bandwidth or waveform - for the purposes of training. Specifically, this work compares in detail the cross-frequency training degradation incurred for several different training approaches and deep neural network (DNN) architectures. Results show a 70% drop in classification accuracy when the RF sensors for pre-training, fine-tuning, and testing are different, and a 15% degradation when only the pre-training data is different, but the fine-tuning and test data are from the same sensor. By using generative adversarial networks (GANs), a large amount of synthetic data is generated for pre-training. Results show that cross-frequency performance degradation is reduced by 50% when kinematically-sifted GAN-synthesized signatures are used in pre-training.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Microwave Sensing, Signals & System
Prenatal Diagnosis of Fetal Hypothyroidism After Maternal Radioactive Iodine Exposure During Pregnancy
No full textA 33-year-old woman with a history of surgically treated papillary thyroid carcinoma was inadvertently given radioactive iodine when she was 16 weeks pregnant. Sonographic examination revealed fetal thyroid hypoplasia, and cordocentesis confirmed fetal hypothyroidism at 22 weeks. The pregnancy was terminated at 24 weeks. We report the first case of fetal thyroid hypoplasia diagnosed by ultrasound and cordocentesis. (C) 2010 Wiley Periodicals, Inc. J Clin Ultrasound 38:506-508, 2010; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/jcu.2073
