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Copyright of Current Research in Dental Sciences is the property of Ataturk University Coordinatorship of Scientific Journals and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Turkiye Klinikleri Journal of Dental Sciences is the property of Turkiye Klinikleri and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Amaç: Işık ile aktive edilmeden, LED ışık kaynağı ile ve Er: YAG lazer ile aktive edilen %40 konsantrasyondaki hidrojen peroksit (HP) beyazlatma jeli ile beyazlatma işleminin renk değişikliğine, yüzeyin mikrosertlik ve pürüzlülük özelliklerine olan etkilerini incelemektir. Gereç ve Yöntem: Çalışmada çekilmiş sağlıklı üçüncü büyük azı dişleri kullanılmıştır. Akrilik bloklara gömülen dişler 2200 grit’e kadar zımpara ile zımparalanarak minede düz yüzeyler elde edilmiştir. Biri kontrol grubu (Grup K) olmak üzere toplam dört grup değerlendirilmiştir. Bunlar; aktivasyon yapılmaksızın beyazlatma jeli uygulanan grup (Grup J), 385-515 nm dalga boyunda ve 3200 mW/cm2 güçte ışık üreten LED ışık kaynağı ile beyazlatma yapılan grup (Grup LED) ve 50 mJ enerji ile10 Hz’de ve VLP modunda (1000 µs atım süresi) ile kullanılan Er:YAG lazer ile aktivasyon yapılan gruptur (Grup Er:YAG). Beyazlatma işleminin öncesinde ve sonrasında spektrofotometre ile renk ölçümü yapılmış ve renk değişimi (∆E00) CIEDE2000 formülü ile hesaplanmıştır. Bir hafta örnekler yapay tükürük içerisinde bekletildikten sonra 980 g yük 15 s boyunca uygulanarak mikrosertlik ölçümleri ve kontakt tipi bir profilometre ile pürüzlülük ölçümleri yapılmıştır. Veriler Oneway ANOVA testi ile değerlendirilmiştir. Bulgular: Beyazlatma yapılan tüm gruplarda renk değişikliği gözle fark edilebilme eşiğinin üzerinde saptanırken gruplar arası anlamlı farklılık bulunmamıştır. Kontrol grubu ile beyazlatma yapılan gruplarda mikrosertlik ve pürüzlülük değerleri anlamlı bir değişim göstermemiştir. Sonuç: Beyazlatma işleminden bir hafta sonra diş minesinin yüzey özellikleri beyazlatma yapılmamış mineden farklı değildir.

Copyright of Selcuk Dental Journal is the property of Selcuk Dental Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Odontologica Turcica is the property of Acta Odontologica Turcica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article discusses a study conducted on the effects of home and over-the-counter whitening agents on dental composites. The study found that different whitening agents had varying effects on the surface roughness and microhardness of the composites. Some composites were more negatively affected by the whitening agents, while others were less affected. The study emphasizes the importance of professional supervision during teeth whitening procedures and raises concerns about the potential harm of unattended whitening with over-the-counter products. The study also suggests that more research is needed to assess the safety of these products. [Extracted from the article]

Objective Glass ionomers are preferred in many different treatment procedures in dentistry due to their positive features. The aim of this study is to evaluate the color difference and microhardness values of various glass ionomer cement after storing them in different solutions. Material and Method A total of 120 samples were prepared, including 40 of each of the Equia Forte, AHfil Silver, and Ionofil glass ionomers. Each glass ionomer sample was stored in distilled water, cola, tea, and coffee solutions. Color and microhardness measurements of the specimens were performed before and after a week before it was immersed in solutions. The color measurements of the samples were evaluated with a spectrophotometer and microhardness values were evaluated with Vickers microhardness device. For color analysis, color changes (ΔE) were calculated by obtaining the values of L*, a*, and b* of the samples before and after a week after being immersed in solutions. The data obtained were evaluated by variance analysis (ANOVA) and Tukey's test. Results Except for specimens stored in cola for AHfil Silver, microhardness values were increased for all materials immersed in test solutions. The highest color change was obtained in coffee for Equia Forte, in the samples immersed in cola for AHfil Silver and Ionophil (p<0.05). The lowest color change was detected in samples stored in distilled water, and for Equia Forte and Ionofil, the color change was below the acceptable threshold value. Conclusion All the materials tested differ in microhardness and color change values after being immersed in the test environment. The increase in microhardness value can be attributed to the increasing maturation of glass ionomer cement over time, and color change can be attributed to the amount of yellow dyestuff contained in the solutions. [ABSTRACT FROM AUTHOR]

In this study, the surfaces of AISI 1050 Medium Carbon Steel and D2 Cold Work Tool Steel, which are commonly used in the machine manufacturing industry, were processed using the burnishing method. In the burnishing experiments, cylindrical materials with dimensions of Ø50x30mm and a Ø20mm hole drilled in the center were used. For the turning process, the cutting speed was selected as 60 m/min and the feed rate as 0.25 mm/rev. The burnishing process was applied in a single pass. The properties such as microhardness, surface morphology, circularity, cylindricality and surface roughness of the materials by the burnishing process were examined in detail. After burnishing, the hardness of AISI 1050 and D2 cold work tool steel materials was measured to be 292 HV and 302 HV, respectively. The results obtained showed that the burnishing process increased the hardness value of AISI 1050 steel proportionally more than the hardness value of D2 steel. It was determined that the circularity and cylindrical properties of the hole surfaces were improved. The obtained results show that the burnishing process will increase the efficiency of the machine elements working in contact and the damage that may occur during the operation of these machine elements can be minimized by burnishing process. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to compare the microhardness of high viscosity glass ionomer, glass carbomer (GC) and bioactive restorative material (BRM) exposed to different polymerization times, and the intrapulpal thermal changes they caused on teeth. Methods: Sixty human molar teeth were used in this study. During Class I cavity preparation,1 mm dentine thickness was left between the pulp chamber and occlusal cavity floor.Teeth were randomly divided into six groups. Group 1: restored with high viscosity glass ionomer cement (HV-GIC), cured for 20 sec., Group 2: restored with HV-GIC, cured for 40sec., Group 3: restored with conventional glass ionomer cement, cured for 60 sec., Group 4: restored with GC and cured for 90 sec., Group 5: restored with BRMs, cured for 20 sec., Group 6: restored with BRM, cured for 40 sec. All glass ionomer cements were polymerized with a LED light curing unit except GC groups. GC groups were cured with a special thermocure lamp. As soon as the materials were placed in the cavities, temperature increase on the tooth during setting/ polymerization reactions were measured with a thermocouple wire connected to a data logger. All of the specimens were polished with discs.Then, microhardness values were evaluated from three different points. Data were analyzed using one-way ANOVA, Tukey test and paired t-tests (p<0.05). Results: Group 2 showed statistically significantly higher increase in temperature when compared to Group 1. Group 4 showed statistically significantly higher temperature than Group 3. There was no significant difference between Groups 5 and 6 in terms of temperature changes. The highest microhardness values were obtained in GC groups, when the groups were compared to each other. Group 2 showed significantly higher microhardness value than Group 1. Group 6 showed significantly higher microhardness values than Group 5. Conclusion: Fourty sec polymerization of the BRM positively affected the microhardness without causing an intrapulpal temperature increase. While high microhardness values were obtained in 90 sec polymerization of GC, it also caused an increase in temperature that would damage the pulp. [ABSTRACT FROM AUTHOR]

The Al-13.6Cu-6Si (wt.%) ternary alloy was solidified upward unidirectional directionally in a Bridgman-type directional solidification furnace at a constant solidification rate (V=17.4 μm/s), different temperature gradients (1.6-6.12 K/mm), and different solidification rates (8.3-166.0 μm/s) at a constant temperature gradient (G=4.64 K/mm). After completion of the solidification process, the alloy samples were subjected to metallographic treatments to reveal their microstructures. The effect of solidification parameters (V and G) on microstructure parameters (λ1 and λ2) was examined. In addition, the dependence of microhardness on solidification rate, temperature gradient, and microstructure parameters was investigated. The results were also compared with similar experimental results reported in the literature. [ABSTRACT FROM AUTHOR]

Copyright of Selcuk Dental Journal is the property of Selcuk Dental Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Current Research in Dental Sciences is the property of Ataturk University Coordinatorship of Scientific Journals and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Meandros Medical & Dental Journal is the property of Galenos Yayinevi Tic. LTD. STI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Ürünleri Dergisi is the property of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Urunleri Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: The aim of this study was to examine the effect of photodynamic therapy (PDT) using toluidine blue O (TBO), curcumin (CUR) and methylene blue (MB) photosensitizers on root canal dentin microhardness by comparing it with sodium hypochlorite (NaOCl) + ethylenediamine tetraacetic acid (EDTA). Materials and methods: The root canals of 100 human premolar teeth were shaped by the R25 file (Reciproc; VDW, Munich, Germany). The working length of the teeth was determined by using a #10 K-file, keeping it 1mm shorter than the tooth apex. The R25 file was used to prepare the root canals. After every three pecking motions, irrigation was performed and a total of 10 mm of distilled water was used. The specimens were randomly distributed according to the disinfection method; NaOCl+EDTA, PDT with TBO, PDT with CUR, PDT with MB and distilled water (DS) (n=20). Grooves were prepared on the buccal and lingual surfaces of the prepared teeth, parallel to the long axis of the tooth, without touching the root canals. The roots were divided into two parts by means of a cement spatula placed in these grooves. Root canal dentin microhardness was evaluated by the Vickers test method. Three measurements were made by applying 300 g of force for 15 seconds and the average was calculated. It was recorded as the Vickers hardness value. The data were analyzed by using the one-way ANOVA and Dunnett’s post hoc tests (α=0.05). Results: All photosensitizer groups showed significantly higher microhardness value than the groups of DS and NaOCl + EDTA (p0.05). Conclusions: PDT with CUR obtained the highest radicular dentin microhardness.

Since gamma radiation is a type of radiation that can change the structural properties of materials, CuAlBe shape memory alloy with two different weight percentages was used in this study. CuAlBe shape memory alloys were irradiated with a constant gamma radiation dose of 40 kGy, and the resulting thermal and structural changes in the alloys were investigated. Changes in enthalpy and in the transformation temperature of the alloys were determined by differential scanning calorimetry (DSC), and thermodynamic parameters of alloy samples were calculated. Microstructural changes were determined by X-ray analysis. Microstructural changes were verified by metallographic observations, and microhardness measurements were taken. The study investigated to what extent the physical parameters of CuAlBe shape memory alloys changed depending on the alloying elements when subjected to a constant irradiation dose. [ABSTRACT FROM AUTHOR]

In this study, Al50Si25B25 alloy was produced as ingot by arc melting method. The microstructure of the Al50Si25B25 alloy was investigated by X-ray diffraction (XRD), the morphological properties were investigated by scanning electron microscopy (SEM), and its thermal properties were investigated by differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The mechanical properties of the alloy were investigated by Vickers microhardness (HV) test. The XRD result showed that B and Si atoms dissolved in the Al lattice to form the intermetallic phase of the a-Al (B, Si) solid solution. XRD and SEM results showed that the microstructure of the alloys consisted of a-Al(B,Si) solid solution, Si and AlB2 intermetallic phases. SEM results showed that the morphological structure of the alloys formed as dendritic and eutectic structures. DSC and DTA results showed an endothermic peak indicating the melting of the a-Al(B,Si) phase. The microhardness value of the alloy was measured as 108±15 HV at room temperature. This value increased as a result of the heat treatment and increased to 232±9 HV at 300 °C. It was observed that the microhardness value of the alloy decreased at temperatures higher than 300 °C. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Polytechnic is the property of Journal of Polytechnic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of this study is to compare the microhardness of five different bulk fill composites (SDR, TEC, XTF, SF, FBF). A total of 25 cylindrical molds were prepared. Composite resin was placed in each mold in sequence, at one time, by condensing it thoroughly. Then, the polymerization of the composites was achieved with the LED light device which was applied for 20 seconds. Microhardness measurements of the samples were made with the classical Vicker's test. The data of our study were evaluated by using the Kruskal Wallis H test with the SPSS 20.0 package program. When the measured surface microhardness values were compared between the groups; microhardness values SDR and FBF groups were found to be significantly lower than TEC, XTF and KSF groups (p<0.05). When the sub-surface microhardness values were compared between the groups; the microhardness value of the SDR group was found to be significantly higher than the FBF group, and significantly lower than the TEC, XTF and KSF groups (p<0.05). When both the lower and upper surface microhardness values were compared between the groups, XTF was found to be the bulk fill composite group with the best microhardness. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ege University School of Dentistry / Ege Üniversitesi Dis Hekimligi Fakültesi Dergisi is the property of Ege University Faculty of Dentistry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Ege University School of Dentistry / Ege Üniversitesi Dis Hekimligi Fakültesi Dergisi is the property of Ege University Faculty of Dentistry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, the effect of different electrode tip types on weld nugget diameter, tensile shear strength and microhardness properties of advanced high strength steel combined with resistance spot welding method was investigated. For this purpose, resistance spot welded joints were performed using conical round, flat R3, flat R6 and flat conical electrode tips, which are preferred especially in the automotive industry. Test samples were subjected to weld nugget geometry macro-micro examination, mechanical and metallurgical investigations. Experimental results showed that there is a linear relationship between weld nugget diameter value, microhardness results and tensile shear strength values. The highest tensile shear strength values were obtained with flat 3 mm radius tip electrodes, and the lowest tensile shear strength values with flat conical tip electrodes. [ABSTRACT FROM AUTHOR]

Bu çalışmada, AISI H11 sıcak iş takım çeliğinin tornalanmasında kriyojenik işlemin kesici takım performansı üzerine etkileri araştırılmıştır. Deneylerde TiAlN+TiN kaplı tungsten karbür takımlar kullanılmıştır. Kesici takımlar üzerine 6 saat süre ile -80 °C’de sığ kriyojenik işlem (SCT6), 6 saat süre ile -196 °C’de derin kriyojenik işlem (DCT6) ve 24 saat süre ile -196 °C’de derin kriyojenik işlem (DCT24) uygulanmıştır. Tornalama deneyleri 0,6 mm kesme derinliği, 0,18 mm/dev ilerleme hızı ve 320, 360, 400 ve 440 m/dak olmak üzere dört farklı kesme hızında gerçekleştirilmiştir. Deneysel sonuçlar kriyojenik işlemin kesici takımın aşınma direncini artırdığını göstermiştir. En düşük kesici takım aşınması ve yüzey pürüzlülüğü değerleri DCT24 takımla elde edilmiştir. Yanak aşınmasında %13-28 oranlarda, yüzey pürüzlülüğünde ise %7-14 oranlarda iyileşmeler gözlenmiştir. Diğer yandan kriyojenik işlemin kesici takımların sertliğinde %4,4-8,7 oranlarda artış sağladığı tespit edilmiştir. En yüksek sertlik artışı da DCT24 takımda meydana gelmiştir.

D2, D6 and Calmax cold work tool steels were heat treated in vacuum hardening, made grinding and plasma nitrided in 75% N2 + 25% H2 atmosphere at 450 °C for 12 h at 2 mbar. Characterization of samples has been carried out by means of surface roughness, microstructure, microhardness and wear-friction. Wear-friction characteristics of samples have been investigated using a ball-on-disc tribosystem with a WC-Co ball. Plasma nitriding increased the surface roughness of samples. However, this effect was decreased with higher surface roughness of base metal. Fe4N (γ'), Fe3N (ε) and CrN phases were obtained on the surfaces of samples. Higher surface hardness was obtained in the plasma nitrided D2 and D6 steels. No significant mass loss was observed in the ball on-disc tribosystem. So, the wear of samples was characterized with the worn surfaces using a scanning electron microscope (SEM). Plasma nitriding improved the wear resistance and decreased the friction coefficient of steels. Plasma nitrided D2 steel showed the highest wear resistance, whereas plasma nitrided Calmax steel exhibited the lowest wear resistance. However, plasma nitrided Calmax tool steel had relatively lower friction coefficient than the other plasma nitrided steels. In general, brittle layer fractures have determined the friction coefficient.

Bu çalışmada, XAR (eXtra Aşınma Dayanımı) çeliklerinin robotik MAG kaynağında kaynak akımının kaynaklı birleştirmelerin mikrosertliği üzerine etkisi incelenmiştir. Bu çalışmada, ağır hizmet makinelerinde kullanılan 4 mm kalınlıktaki XAR 500 çeliğinin MAG kaynak yöntemiyle birleştirilmesinde kaynak akımı yoğunluğunun mikrosertliğe etkisi incelenmiştir. Kaynaklanmış numunelerin hazırlanmasında hız, gerilim ve akım kontrollü MAG kynak robotu kullanılmıştır. 140A, 160A ve 180A olmak üzere üç farklı kaynak akım yoğunluğu seçilmiştir. Kaynak hızı 350mm/dak olarak sabit tutulmuştur. Kaynak hızının etkisini test etmek için 300mm/dak, 350mm/dak, 400mm/dak ve 450 mm/dak. olarak seçilmiş kaynak akım şiddeti 160A’ de sabit tutulmuştur. 1 mm kalınlığında MG-2 kaynak teli kullanılmıştır. %86 Ar, %12 CO2 ve %2 O2 içeren karışım gaz kullanılmıştır. Sonuç olarak, bu malzeme gruplarının kaynaklı bağlantılarında ısı tesiri altındaki bölge (ITAB) sertliğinin azaldığı gözlenmiştir. Bu nedenle ITAB sertliğinin azalması durumunda çatlak riskinin azaldığı gözlenmiştir. Elde edilen kaynaklı bağlantılarda optimum sertlik oranını sağlayan kaynak akımı ve kaynak hızı kullanıcılara sunulmuştur.

Amaç: Bu in vitro çalışmada kompozit restorasyonların şekillendirilmesinde kullanılan farklı tiplerdeki rezin içerikli modelasyonlikitlerinin mikrohibrit bir kompozitin yüzey mikrosertliğine, pürüzlülüğüne ve renk değişimine olan etkisini incelemek amaçlandı. Gereç ve Yöntemler: Çalışmada kullanılmak üzere 12 mm çapında ve 2 mm yüksekliğinde Teflon kalıp ile silindir şeklinde 64 adet mikrohibrit kompozit (Essentia Universal, GC, Tokyo, Japonya) örnek şu şekilde gruplara göre hazırlandı; Grup 1: Kontrol (modelasyon likidi kullanılmadan), Grup 2: Modeling Liquid (GC), Grup 3: G-Premio Bond (GC), Grup 4: OptiBond XTR Primer (KavoKerr). Şekillendirmede kullanılan modelasyon likitleri sadece mikrohibrit kompozit yerleştirilirken uygulandı ve örneklerin üst yüzeyine şeffaf bant yerleştirildi, sonra 20 sn polimerize edildi. Örneklere 2500-3000 gritlik SiC-kağıtlar ile polisaj yapıldı ve 37°C’deki inkübatörde saklanma ortamına göre (distile su vaya kahve) rastgele 2 gruba ayrıldı (n=8). Yüzey mikrosertliği (VHN), pürüzlülüğü (Ra) ve renk değişimi (ΔE) 24 saat, 1 hafta ve 6 hafta sonra ölçüldü. Veriler ANOVA ve Kruskall Wallis testleri ile analiz edildi (p=0.05). Bulgular: Saklama ortamı ve zaman mikrohibrit kompozitin yüzey mikrosertliğini hiçbir grupta etkilemedi (p>0.05). Modeling Liquid uygulanması örnekler kahvede saklandığında tüm saklama süreleri için örneklerin pürüzlüğünü olumlu yönde etkiledi (p

Copyright of Journal of Polytechnic is the property of Journal of Polytechnic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background:To investigate the effects of final irrigation protocols with tannic acid (TA) on dentin microhardness and push-out bond strength of an epoxy resin based sealer to root canal dentin.Methods: The 50 root halves were embedded in an acrylic resin for the microhardness measurement. After the initial baseline microhardness measurement, the root halves were randomly divided into 5 groups according to the final irrigation protocol used (n=10): distilled water (control), 10% TA for 2 min, 10% TA for 5 min, 20% TA for 2 min, and 20% TA for 5 min. After surface treatment, dentin microhardness values were recorded at close proximity to the initial indentation areas. For push-out bond strength test the root canals of 75 single-rooted mandibular premolars were instrumented and the final irrigation protocols were applied as described above (n = 15). Following root canal obturation with single cone technique using matched-taper gutta percha cones and an AH Plus- epoxy resin based root canal sealer, 1 mm-thick slices were obtained from the middle third of the root canals. Push-out bond strength test was applied. The data were analyzed using One way ANOVA and Tukey HSD tests (p=0.05).Results:In TA-treated groups, there was a significant increase in the microhardness values compared with the control group (p0.05). The remaining groups presented higher bond strength values than the control group (p

Amaç: Bu in vitro çalışmanın amacı farklı posterior kompozitlerin su emilimi, çözünürlük ve mikrosertlik değerlerinin zaman içinde değişimlerini incelemektir.Gereç ve Yöntem: Çalışmada beş farklı kompozit (Ceram-X One Universal-Dentsply, G-aenial posterior-GC, Charisma Smart-Heraus Kulzer, X-tra fil-Voco ve Filtek Z550-3M ESPE) ve bir cam iyonomer siman (Ketac Molar Easymix-3M ESPE) kullanıldı. Materyallerin su emilimi ve suda çözünürlükleri ISO 4049 standartlarına göre incelendi. Materyallerin üç farklı zaman aralığında (başlangıç, 28 gün suda bekletme sonrası ve 90 gün desikatörde bekletme sonrası) mikrosertlik ölçümleri yapıldı. Verilerin istatistiksel analizi % 95 güven aralığında tek yönlü varyans analizi (ANOVA) ve Bonferroni testi ile gerçekleştirildi.Bulgular: Tüm kompozit materyaller ISO 4049 kriterlerine uygun olarak 40 µg/mm3’den daha az su emilimi gösterdi. Bu kriterlere uymayan ve en yüksek su emilimi değeri Ketac Molar Easymix’de (78.44±5.14 µg/mm3) saptandı (p

Although it has a lot of usage area in the industry because the Al-Cu alloy is defined among the base alloys, the uncontrolled solidified casting of this alloy does not always have the desired properties and performance. For the production of Al-Cu alloys with superior properties, the solidification parameters known as the solidification rate, temperature gradient and composition ratio are changed and the results of this change are evaluated. It is known that changing the properties of the microstructure by growth rate affects the mechanical, electrical and thermal properties of the materials. For this reason, Al-%33 wt. Cu eutectic composition to carrying out correctly microstructure evaluation was prepared, then controlled solidification experiments were carried out by a Bridgman type furnace at a constant temperature gradient (G = 8.50 K/mm) and at five different growth ratios (V = 8.25˗164.80 μm/s). Thus, the effect of the growth rate on the microstructure was investigated and values of microhardness, tensile strength and electrical resistivity were investigated with the effect of change in the microstructure. Both linear regression analysis and Hall-Petch type correlations were used to determine the relationship between microstructure, microhardness, tensile strength and electrical resistivity values. The results obtained in this work were compared with the previous similar experimental results. [ABSTRACT FROM AUTHOR]

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ÖzetAmaç: bu çalışma üç farklı bulk fill kompozit (Surefil SDR flow, Dentsply, Caulk, USA and Tetric, EvoCeram, Ivoclar Vivadent, Schaan, Liechtenstein, X-tra base, Voco, Cuxhaven, Germany) mikrosertliklerinin araştırılmasıdır.Gereç Yöntem: Çalışma için 4mm ve 2mm kalınlığında 4mm yarı çapında hazırlanan herbir bulk fill kompozit Plama ark ışık kayanağı kullanılarak polimerize edildi. Her bir örneğin alt ve üst mikrosertlik değerlendirmeleri Vickers mikrosertlik test cihazı kullanılarak yapıldıBulgular: çalışmada kullanılan tüm materyallerin polimerizasyonu ışık kaynağı ile yapıldıktan sonra alt yüzeylere ait sertlik değeri üst yüzeylerden daha düşük bulundu. Tüm komozitler arasında en yüksek Vickers sertlik değeri (40.02±4.06) olan grup üst Xtra base bulk fill kompozitine aitdir. En düşük Vickers sertlik değeri (5.80±0.83) alt ölçüm yapılan SDR bulk fill grubuna aittir.Sonuç: Tüm örnek gruplarına ait sertlik oranı 0.80 den daha düşük bulundu.örnek gruplarına ait sertlik oranı 0,19±0,3 ile 0,72±0,06 arasındadır.Anahtar kelimeler: mikrosertlik, akışkan kompositler, sertlik oranı

Current caries removal methods are classified in various categories including rotating instruments (burs) or excavator, mechanical methods performed by air abrasion, ultrasonic and sono-abrasion, chemomechanical and photoablation (lasers) methods. While conventional caries removal methods are effective, chemomechanical methods were developed to avoid from some possible disadvantages. The action mechanism of chemomechanical caries removal method is based on use of an solution to chemically alter caries tooth tissue to further soften it thus its easier removal. The altered dentine tissue is then mechanicallly removed with hand instruments. Chemomechanical method is claimed to remove caries tissue by only removing the infected dentine layer selectively without causing pain and intact hard tooth tissue loss. Furthermore, the bactericidal and bacteriostatic effects of the method and absence of potential deleterious effects to dental pulp due to heat and pressure make it to be considered as an alternative caries removal method. The aim of this study is to provide information about sodium hypochlorite and enzyme based chemomechanical caries removal agents. Advantages and disadvantages of the method as well as the caries removal efficacy will be examined together with the findings obtained from laboratory and clinical studies on the presence of residual caries and bacteria, micro-hardness and chemical structure of the dentine. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to examine the effect of early exposure to water and the efficiency of nanofilled self-adhesive lightcured protective resin coating on the microhardness of highly viscous conventional glass ionomer cement. Material and methods: Twenty-four samples were prepared in 2 mm thickness and 5 mm diameter using highly viscous glass ionomer cement. Protective resin coating (G-Coat Plus, GC) was applied onto the entire surfaces of the half of the samples according to the manufacturer’s instructions. The samples then were stored in distilled water at 37ºC for 1 month. Microhardness measurements of the samples were carried out after 24 hours, 2 weeks and 1 month. The data were analyzed by repeated measures of ANOVA, Sheffe F and independent t-tests. Results: The microhardness values of uncoated group were observed to gradually increase throughout 24 hours, 2 weeks and 1 month measurement times (p