Stress Distribution on Various Implant-Retained Bar Overdentures.

The purpose of this study was to evaluate the effects of various fabrication techniques and materials used in implant-supported mandibular overdentures with a Hader bar attachment over added stress distribution. Three-dimensional geometric solid models, consisting of two implants (3.3 mm × 12 mm) placed at the bone level on both mandibular canine regions and a Hader bar structure, were prepared. Model 1 simulated a bar retentive system made from Titanium Grade 5 material by Computer Numerical Control (CNC) milling technique without using any converting adapter/multi-unit element on the implants, while Model 2 simulated the same configuration, but with converting adapters on the implants. Model 3 simulated a bar retentive system made from Cobalt-Chromium material, made by using conventional casting technique with converting adapters on the implants. Static loads of 100 Newton were applied on test models from horizontal, vertical and oblique directions. ANSYS R15.0 Workbench Software was used to compare Von Mises stress distribution and minimum/maximum principal stress values, and the results were evaluated by using Finite Element Analysis method. As a result, the highest stress distribution values under static loading in three different directions were obtained in Model 1. Stress was observed intensely around the necks of the implants and the surrounding cortical bone areas in all models. In scope of the results obtained, using converting adapters on implants has been considered to decrease transmission of forces onto implants and surrounding bone structures, thus providing a better stress distribution. It has also been observed that the type of material used for bar fabrication has no significant influence on stress values in those models where converting adapters were used

Monolitik zirkonya materyalinin fizikokimyasal başarılarının istatistiksel olarak değerlendirilmesi

Amaç: Monolitik zirkonya materyali son yıllarda klinik endikasyon çeşitliliğinin artması ile ve materyal bilimindeki gelişmelerin sayesinde protetik diş hekimliğinde restorasyon materyalleri arasında oldukça önemli bir yere sahiptir. Bu tez çalışmasında, iki farklı yöntem ile renklendirilmiş stabilize edici oksit ve faz içeriği değişkenlik gösteren monolitik zirkonya materyallerinde, çeşitli yüzey bitirme işlemleri, kimyasal yaşlandırma ve renklendirici ajan uygulamalarını takiben görülebilecek olası renk değişikliği, yüzey pürüzlülüğü ve temas açısı farklılıklarını in-vitro olarak incelemek amaçlanmıştır. Yöntem: %4-6 Y2O3 içerikli (Vita YZ HT, Vita Zahnfabrik, Bad Sackingen, Almanya) ve %9,32 Y2O3 içerikli (CopraSmile, Whitepeaks Dental Solutions GmbH;Co, Essen, Almanya) renkli ve renksiz translüsent zirkonya bloklardan 144 adet disk şeklinde örnek (1.2 mm Ø ± 0.2 mm) kazıma yöntemi ile hazırlandı. Renksiz bloklardan kazınan örneklere renklendirme sıvısı ile sinterlenme öncesinde internal renklendirme yapıldı. Örneklere ağız içi okluzal aşındırmayı taklit eden bir pürüzlendirme işlemi sonrasında glaze, ağız içi polisaj kiti (NTI, NTI-Kahla GmbH Rotary Dental Instruments, Kahla, Almanya) ve polisaj pastası içeren ağız içi polisaj seti (OptraFine, Ivoclar Vivadent AG, Schaan, Liechstenstein) ile yüzey bitirme işlemleri uygulandı (n=12). Ardından, örneklere pH değeri 2,4 olan %4’lük asetik asit çözeltisinde kimyasal yıpratma işlemi termostatik çalkalama cihazında (4080 Incubator Shaker, Herasau, İsviçre) 18 saat boyunca 80°C’ye kadar kademeli sıcaklık artışı ile uygulandı. Son aşamada, 2 gr granül kahve (Nescafe Classic, Nestle, İstanbul, Türkiye) ve 200 ml kaynar su ile renklendirici ajan karışımı hazırlandı ve örnekler 7 gün boyunca bu karışımda bekletildi. Tüm örneklerin başlangıçta, yüzey bitirme işlemi sonrasında, yaşlandırma sonrasında yüzey pürüzlülükleri manuel profilometre yardımıyla (Sj 201, Mitutoyo Corp, Kawasaki, Japonya), temas açıları ise temas açısı mikroskobu ile (Krüss GmbH, Hamburg, Almanya) ölçüldü. ΔE hesaplaması için gereken L, a, b değerleri de Vita Easyshade Spektrofotometre (Vita Zahnfabrik, Bad Sackingen, Almanya) ile başlangıçta, yüzey bitirme işlemi sonrasında, yaşlandırma sonrasında ve renklendirici ajan sonrasında ölçüldü. Elde edilen verilerin istatistiksel analizi IBM SPSS Statistics for Windows, Version 25.0.(IBM Corp. Released 2017, Armonk, NY) paket programında tamamlandı. Bulgular: 3Y-TZP translüsent bloklardan elde edilen 72 adet örneğin başlangıç temas açısı ölçümlerinde ortalama ve standart sapma 39,21±5,88 derecedir. 5Y-PSZ translüsent bloklardan elde edilen örneklerin başlangıç temas açısı ölçümlerinin ortalaması ve standart sapma 36,21±6,79 derecedir. Gruplar 3: 3Y-TZP, 5: 5Y-PSZ, Ö: Önceden renkli (preshaded), S: Sonradan renklendirilen (sinterlenme öncesi renklendirilen) bleach blok, G: Glaze, AP: Ağız içi parlatma kiti ve PP: Polisaj pastası içeren polisaj seti olarak kodlandırılmıştır. 3 Ö G, 3 Ö AP, 3 Ö PP, 3 S G, 3 S AP, 3 S PP, 5 Ö G, 5 Ö AP, 5 Ö PP, 5 S G, 5 S AP ve 5 S PP temas açı ortalama ve standart sapma değerleri sırasıyla 37,17±5,81, 41,67±4,46, 53,42±6,80, 31,75±5,93, 45,58±7,80, 47,42±3,32, 34,08±6,22, 38,83±7,16, 43,92±6,29, 28,33±6,30, 33,17±8,18 ve 43,42±6,10 derecedir. 3 Ö G, 3 Ö AP, 3 Ö PP, 3 S G, 3 S AP, 3 S PP, 5 Ö G, 5 Ö AP, 5 Ö PP, 5 S G, 5 S AP ve 5 S PP Ra değerleri ortalama ve standart sapma değerleri sırasıyla 1,31±0,29, 0,84±0,21, 0,77±0,28, 1,44±0,36, 0,95±0,34, 0,60±0,21, 1,29±0,22, 0,71±0,18, 0,81±0,25, 1,13±0,24, 0,86±0,25 ve 0,96±0,27 şeklindedir. Ayrıca, ΔE1 değerleri tüm gruplarda eşik değerin altındadır. ΔE6 değerleri ise eşik değeri aşmıştır; her grupta en düşük değerler AP, en yüksek değerler PP grubundadır. Sonuç: Düşük yttrium içerikli, yüksek yttrium içerikli, önceden ve sonradan renklendirilmiş glaze uygulaması gruplarının hepsinde (3 Ö, 3 S, 5 Ö, 5 S) temas açısı değerleri azalmıştır. Kimyasal yaşlandırma sonrasında tüm grupların temas açılarında artış vardır. Düşük yttrium içerikli, yüksek yttrium içerikli, önceden ve sonradan renklendirilmiş glaze uygulanan grupların tümünün (3 Ö, 3 S, 5 Ö, 5 S) Ra değerleri, ağız içi polisaj kiti (AP) ve polisaj pastası içerikli polisaj seti (PP) gruplarına göre daha yüksektir. Kimyasal yaşlandırma sonrasında tüm gruplarda Ra değerleri artmıştır. Yüzey bitirme işlemi ve kimyasal yaşlandırmanın oluşturduğu renk değişimi değerleri eşik değerin altındadır ancak kahve renklendirmesi sonrasında tüm kübik zirkonya gruplarında değerler eşik değerin üzerine çıkmıştır.Purpose: Monolithic zirconia has a very important place among restoration materials in prosthetic dentistry, owing to the increase in the variety of clinical indications and developments in material science in recent years. This PhD thesis aims to investigate the color stability, surface roughness and contact angle differences that can be observed after various surface finishing methods, chemical aging (acid corrosion) and coloring agent applications in preshaded and internally shaded monolithic zirconia materials whose Y2O3 and cubic phase content vary. Method: Disc-shaped samples (1.2 mm Ø ± 0.2 mm) (n=144) were prepared by subtractive milling of preshaded and bleach monolithic zirconia blocks with 4-6% Y2O3 content (Vita YZ HT, Vita Zahnfabrik, Bad Sackingen, Germany) (n=72) and 9.32% Y2O3 content (CopraSmile, Whitepeaks Dental Solutions GmbH;Co, Essen, Germany) (n=72). The samples milled from the bleach blocks were internally shaded with the coloring liquid and sintered. In order to symbolise the intraoral occlusal grinding process, Z-Cut (NTI-Kahla GmbH Rotary Dental Instruments, Kahla, Germany) diamond burs were used. Then, various surface finishing;polishing methods including glaze, intraoral polishing kit (NTI, NTI-Kahla GmbH Rotary Dental Instruments, Kahla, Germany) and intraoral polishing set with a diamond paste (OptraFine, Ivoclar Vivadent AG, Schaan, Liechstenstein) were applied 12 samples of each 4 subgroups. All samples were aged chemically in a 4% acetic acid solution (pH=2.4) for 18 hours in a thermostatic shaking device (4080 Incubator Shaker, Herasau, Switzerland). The temperature was gradually increased up to 80°C. Following this step, a coloring agent coffee solution (2 g of granulated coffee (Nescafe Classic, Nestle, Istanbul, Turkey) and 200 ml of boiling water), was prepared and the samples were kept in this mixture for 7 days. Surface roughness and contact angles of all samples at the beginning, after surface finishing and after chemical aging was measured by a manual profilometer (Sj 201, Mitutoyo Corp, Kawasaki, Japan) and contact angle goniometer microscope (Krüss GmbH, Hamburg, Germany). The L, a, and b values were measured at the beginning and after each step of surface polishing, chemical aging and coloring agent application with the help of Vita Easyshade Spectrophotometer (Vita Zahnfabrik, Bad Sackingen, Germany). The ΔE values were calculated according to the formula. Statistical analysis of the obtained data was completed with IBM SPSS Statistics for Windows, Version 25.0.(IBM Corp. Released 2017, Armonk, NY) program. Results: The mean and standard deviation of the initial contact angle measurements of 72 samples obtained from 3Y-TZP translucent blocks were 39.21±5.88 degrees. The mean and standard deviation of the initial contact angle measurements of the samples obtained from the 5Y-PSZ translucent blocks were 36.21±6.79 degrees. The sub-groups were given codes as %3: 3Y-TZP, %5: 5Y-PSZ, Ö: Preshaded, S: Bleach, G: Glaze, AP: Intraoral polish kit, PP: Intraoral polish set containing polishing paste. The mean and standard deviation of contact angle values of 3 Ö G, 3 Ö AP, 3 Ö PP, 3 SG, 3 S AP, 3 S PP, 5 Ö G, 5 Ö AP, 5 Ö PP, 5 SG, 5 S AP and 5 S PP groups are 37.17±5.81, 41.67±4.46, 53.42±6.80, 31.75±5.93, 45.58±7.80, 47.42±3.32, 34.08±6.22, 38.83±7.16, 43.92±6.29, 28.33±6.30, 33.17±8.18 and 43.42±6.10 degrees, respectively. The mean and standard deviation of Ra values of 3 Ö G, 3 Ö AP, 3 Ö PP, 3 SG, 3 S AP, 3 S PP, 5 Ö G, 5 Ö AP, 5 Ö PP, 5 SG, 5 S AP and 5 S PP groups are 1.31±0.29, 0.84±0.21, 0.77±0.28, 1.44±0.36, 0.95±0.34, 0.60±0.21, 1.29±0.22, 0.71±0.18, 0.81±0.25, 1.13±0.24, 0.86±0.25, and 0.96±0.27, respectively. ΔE1 values are below the threshold value, but after the coffee agent, the ΔE6 values exceeded the threshold value in all groups. Among the ΔE6 groups, the lowest ΔE1 values were observed in AP groups, whereas the PP groups exhibited the highest values in all groups. Conclusion: Contact angle values decreased in all groups of glaze application with low yttrium content, high yttrium content, pre-shaded and internal shaded specimens (3 Ö, 3 S, 5 Ö, 5 S). After chemical aging, the contact angles were increased in all groups. Ra values of all (3 Ö, 3 S, 5 Ö, 5 S) glazed groups with low yttrium content, high yttrium content, pre-shaded and internal shaded is higher when compared to the intraoral polishing kit (AP) and polishing set with polishing paste (PP) groups. The Ra values increased in all groups after chemical aging. ΔE values after surface finishing and chemical aging were below the threshold value, but ΔE6 values after the chemical aging and coloring agent exceeded the threshold value in all cubic zirconia groups

Farklı Yöntemler ile Üretilen Tüm Seramik RestorasyonlarınMarjinal Uyumu

Protetik diş hekimliğinde geliştirilen yeni sistemlerin kullanılması ile hem hastaların estetik istekleri karşılanmakta hem derestorasyonların uzun dönem başarısı artmaktadır. Tam seramik sistemlerin estetik gereksinimleri yüksek oranda karşılamaları, üzerinde yapılmış pek çok çalışmayla bir soru işareti teşkil etmezken; bir sabit restorasyonun uzun dönem başarısı için anahtar roloynayan marjinal uyum ve mikrosızıntı açısından da bu sistemler irdelenmelidir. Bu derlemenin amacı, estetik amaçlı kullanılan tüm seramik restorasyon materyallerinin üretim sistemlerinden ve yöntemlerindenkaynaklı olarak görülebilecek marjinal uyum farklılıklarını araştırmaktır. Bu amaçla Pubmed üzerinde dental dergiler arasında 2000’den günümüze yayınlanmış makalelerde ‘CAD-CAM’, ‘Dental Seramik’ ve‘Marjinal Uyum’ MeSH (Medikal Subject Heading) Medikal Konu Başlığı anahtar kelimeleri ile kapsamlı bir arama yapılmıştır. Filtreolarak İngilizce dili ve diş hekimliği dergi makalesi seçilmiştir. İmplant, endokron, internal uyum kelimeleri araştırmadan çıkarılmıştır.Başlangıçta toplam 174 makale belirlenmiştir. Konu ile tam bağdaşmayanlar elendiğinde toplamda 49 makale bu derlemenin çatısınıoluşturmuştur. Ek yayınlar için alınan tüm makalelerin bibliyografyasına danışılmıştır. 1970' den de itibaren elle arama yapılan bazıklasikleşmiş yayınlar çalışmaya dahil edilmiştir.Tam seramik sistemlerle ilgili uzun süreli klinik randomize çalışmaların yeterli olmayışı, bu konudaki görüşleri in vitro çalışmalarüzerinden kurmamıza neden olmakla beraber in vitro çalışmalarda da geniş çalışma grupları ile yapılmış çalışmalar az miktardadır

Mass transport coefficients of different nanofiltration membranes for biologically pre-treated textile wastewaters

According to the Nernst-Planck equation, the Bs (mass transfer coefficient) and Rs (overall removal rate) values for different membrane pressures are obtained from intercept in a straight line relationship between 1/R and 1/Jv. Nernst-Planck equation was determined to be compatible due to an increase in removal rate with increasing pressure. An experimental result showed that NP030 membrane was very feasible for both wastewaters. Published by Elsevier By.TUBITAK-CAYDAGTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [107Y060]; YTU-BAPYildiz Technical University [27-05-02-02]This study was supported by TUBITAK-CAYDAG project no: 107Y060 and YTU-BAP project no: 27-05-02-02

The evaluation of fouling effects in membrane process dealing with the biologically pre-treated textile effluents

Wastewater reuse is necessary in the textile industry due to its consumption of large amounts of freshwater. However, the main problem with the membranes is the decline of permeate flux due to the accumulation of organic and inorganic molecules on the membrane surface when the raw wastewater is used. This study focused on the fouling effect of aerobically and anaerobically pre-treated textile industry effluents using ultrafiltration (UC010) and nanofiltration (NP010 and NP030) membrane processes. Ultrafiltration (UF) and nanofiltration (NF) membranes were applied sequestered (UF or NF) and combined (UF + NF) to treat effluents from a full-scale aerobic sequencing batch reactor (SBR), which is present in the factory, and a laboratory-scale anaerobic treatment plant, namely the static granular bed reactor (SGBR). Membrane experiments at 10 bar operating pressure were carried out on the laboratory scale to obtain better results. Initial fluxes with NP010 seriously declined after 24 h during the long-term experiments (96 h). According to the membrane flux decline and the fouling rates, aerobically pre-treated textile wastewater was better than anaerobically pre-treated textile wastewater, suggesting that dissolved organic matter formed in the anaerobic treatment processes.TUBITAK-CAYDAGTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [107Y060]; YTU-BAPYildiz Technical University [27-05-02-02]This study was supported by TUBITAK-CAYDAG project no. 107Y060 and YTU-BAP project no. 27-05-02-02

Stress Distribution on Various Implant-Retained Bar Overdentures

The purpose of this study was to evaluate the effects of various fabrication techniques and materials used in implant-supported mandibular overdentures with a Hader bar attachment over added stress distribution. Three-dimensional geometric solid models, consisting of two implants (3.3 mm × 12 mm) placed at the bone level on both mandibular canine regions and a Hader bar structure, were prepared. Model 1 simulated a bar retentive system made from Titanium Grade 5 material by Computer Numerical Control (CNC) milling technique without using any converting adapter/multi-unit element on the implants, while Model 2 simulated the same configuration, but with converting adapters on the implants. Model 3 simulated a bar retentive system made from Cobalt-Chromium material, made by using conventional casting technique with converting adapters on the implants. Static loads of 100 Newton were applied on test models from horizontal, vertical and oblique directions. ANSYS R15.0 Workbench Software was used to compare Von Mises stress distribution and minimum/maximum principal stress values, and the results were evaluated by using Finite Element Analysis method. As a result, the highest stress distribution values under static loading in three different directions were obtained in Model 1. Stress was observed intensely around the necks of the implants and the surrounding cortical bone areas in all models. In scope of the results obtained, using converting adapters on implants has been considered to decrease transmission of forces onto implants and surrounding bone structures, thus providing a better stress distribution. It has also been observed that the type of material used for bar fabrication has no significant influence on stress values in those models where converting adapters were used

SARcopenia Assessment in Hypertension: The SARAH Study.

© 2022 Wolters Kluwer Health, Inc.Objectives: The aims of the study were to investigate the relationship between sarcopenia and renin-angiotensin system-related disorders and to explore the effects of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers on muscle mass/function and physical performance. Design: This multicenter, cross-sectional study was performed using ISarcoPRM algorithm for the diagnosis of sarcopenia. Results: Of the 2613 participants (mean age = 61.0 ± 9.5 yrs), 1775 (67.9%) were hypertensive. All sarcopenia-related parameters (except chair stand test in males) were worse in hypertensive group than in normotensive group (all P < 0.05). When clinical/potential confounders were adjusted, hypertension was found to be an independent predictor of sarcopenia in males (odds ratio = 2.403 [95% confidence interval = 1.514-3.813]) and females (odds ratio = 1.906 [95% confidence interval = 1.328-2.734], both P < 0.001). After adjusting for confounding factors, we found that all sarcopenia-related parameters (except grip strength and chair stand test in males) were independently/negatively related to hypertension (all P < 0.05). In females, angiotensin-converting enzyme inhibitors users had higher grip strength and chair stand test performance values but had lower anterior thigh muscle thickness and gait speed values, as compared with those using angiotensin II receptor blockers (all P < 0.05). Conclusions: Hypertension was associated with increased risk of sarcopenia at least 2 times. Among antihypertensives, while angiotensin-converting enzyme inhibitors had higher muscle function values, angiotensin II receptor blockers had higher muscle mass and physical performance values only in females

Acute kidney disease beyond day 7 after major surgery: a secondary analysis of the EPIS-AKI trial

Purpose: Acute kidney disease (AKD) is a significant health care burden worldwide. However, little is known about this complication after major surgery. Methods: We conducted an international prospective, observational, multi-center study among patients undergoing major surgery. The primary study endpoint was the incidence of AKD (defined as new onset of estimated glomerular filtration rate (eCFR) &lt; 60&nbsp;ml/min/1.73&nbsp;m2 present on day 7 or later) among survivors. Secondary endpoints included the relationship between early postoperative acute kidney injury (AKI) (within 72&nbsp;h after major surgery) and subsequent AKD, the identification of risk factors for AKD, and the rate of chronic kidney disease (CKD) progression in patients with pre-existing CKD. Results: We studied 9510 patients without pre-existing CKD. Of these, 940 (9.9%) developed AKD after 7&nbsp;days of whom 34.1% experiencing an episode of early postoperative-AKI. Rates of AKD after 7&nbsp;days significantly increased with the severity (19.1% Kidney Disease Improving Global Outcomes [KDIGO] 1, 24.5% KDIGO2, 34.3% KDIGO3; P &lt; 0.001) and duration (15.5% transient vs 38.3% persistent AKI; P &lt; 0.001) of early postoperative-AKI. Independent risk factors for AKD included early postoperative-AKI, exposure to perioperative nephrotoxic agents, and postoperative pneumonia. Early postoperative-AKI carried an independent odds ratio for AKD of 2.64 (95% confidence interval [CI] 2.21-3.15). Of 663 patients with pre-existing CKD, 42 (6.3%) had worsening CKD at day 90. In patients with CKD and an episode of early AKI, CKD progression occurred in 11.6%. Conclusion: One in ten major surgery patients developed AKD beyond 7&nbsp;days after surgery, in most cases without an episode of early postoperative-AKI. However, early postoperative-AKI severity and duration were associated with an increased rate of AKD and early postoperative-AKI was strongly associated with AKD independent of all other potential risk factors