Comparison of the marginal adaptation of direct and indirect composite inlay restorations with optical coherence tomography

Objective The purpose of the study was to use the photonic imaging modality of optical coherence tomography (OCT) to compare the marginal adaptation of composite inlays fabricated by direct and indirect techniques. Material and Methods Class II cavities were prepared on 34 extracted human molar teeth. The cavities were randomly divided into two groups according to the inlay fabrication technique. The first group was directly restored on cavities with a composite (Esthet X HD, Dentsply, Germany) after isolating. The second group was indirectly restored with the same composite material. Marginal adaptations were scanned before cementation with an invisible infrared light beam of OCT (Thorlabs), allowing measurement in 200 µm intervals. Restorations were cemented with a self-adhesive cement resin (SmartCem2, Dentsply), and then marginal adaptations were again measured with OCT. Mean values were statistically compared by using independent-samples t-test and paired samples t-test (

Evaluation of spinal-paraspinal parameters to determine segmentation of the vertebrae

Purpose: We aimed to evaluate whether lumbar vertebrae can be correctly numbered using auxiliary parameters. Material and methods: Vertebra corpus shape, O’Driscoll classification, lumbosacral axis angle, last two square vertebra dimensions, orifice of right renal artery (RRA), orifice of celiac truncus (CT), orifice of superior mesenteric artery (SMA), vena cava inferior confluence (CVC), abdominal aorta bifurcation (AB), and iliolumbar ligament were evaluated in this study. Results: Lumbosacral transitional vertebrae (LSTV) were observed in 13 (9%) patients. The most common locations of the paraspinal parameters were: RRA: L1 vertebrae (45%), SMA: L1 vertebrae (66%), CT: T12 vertebrae (46%), AB: L4 vertebrae (63%), and CVC: L4 vertebrae (52%). Conclusions: According to the results of our study, no single parameter in the magnetic resonance imaging can accurately indicate the number of vertebrae without counting the levels. As a result, we believe that these parameters may be suspicious in terms of the presence of LSTV rather than the correct level

Magnetic resonance elastography: basic principles, technique, and clinical applications in the liver

Magnetic resonance elastography (MRE) is a constantly advancing technique for assessment of stiffness of tissues with newer technology and sequences. It is being increasingly used for the assessment of liver fibrosis. In this article, we discuss the advantages of MRE over biopsy and noninvasive methods such as US elastography in the assessment of liver fibrosis. Image acquisition and interpretation of liver MRE is also discussed

Comparison of the marginal adaptation of direct and indirect composite inlay restorations with optical coherence tomography

OBJECTIVE: The purpose of the study was to use the photonic imaging modality of optical coherence tomography (OCT) to compare the marginal adaptation of composite inlays fabricated by direct and indirect techniques. MATERIAL AND METHODS: Class II cavities were prepared on 34 extracted human molar teeth. The cavities were randomly divided into two groups according to the inlay fabrication technique. The first group was directly restored on cavities with a composite (Esthet X HD, Dentsply, Germany) after isolating. The second group was indirectly restored with the same composite material. Marginal adaptations were scanned before cementation with an invisible infrared light beam of OCT (Thorlabs), allowing measurement in 200 µm intervals. Restorations were cemented with a self-adhesive cement resin (SmartCem2, Dentsply), and then marginal adaptations were again measured with OCT. Mean values were statistically compared by using independent-samples t-test and paired samples t-test (p<0.05), before and after cementation. RESULTS: Direct inlays presented statistically smaller marginal discrepancy values than indirect inlays, before (p=0.00001442) and after (p=0.00001466) cementation. Marginal discrepancy values were increased for all restorations after cementation (p=0.00008839, p=0.000000952 for direct and indirect inlays, respectively). The mean marginal discrepancy value of the direct group increased from 56.88±20.04 µm to 91.88±31.7 µm, whereas the indirect group increased from 107.54±35.63 µm to 170.29±54.83 µm. Different techniques are available to detect marginal adaptation of restorations, but the OCT system can give quantitative information about resin cement thickness and its interaction between tooth and restoration in a nondestructive manner. CONCLUSIONS: Direct inlays presented smaller marginal discrepancy than indirect inlays. The marginal discrepancy values were increased for all restorations that refer to cement thickness after cementation

Basamak ve alt yapıları farklı zirkonya restorasyonların kırılma direncinin incelenmesi

Bu tezin, veri tabanı üzerinden yayınlanma izni bulunmamaktadır.Yayınlanma izni olmayan tezlerin basılı kopyalarına üniversite kütüphaneniz aracılığı ile (TÜBESS üzerinden) erişebilirsiniz.The aim of this study was to evaluate the effect of different finish lines and framework designs on fracture strengths of zirconia molar crowns. The fracture strength of monolithic zirconia crowns were also evaluated. Three prefabricate acrylic mandibular first molar teeth were prepared with a shoulder (S), chamfer (C) and knife-edge (K) finish lines. For each finish line, 22 silicone impressions were made in order to duplicate the prepared tooth into cobalt-chromium dies, additionally 11 impression were made from chamfer group to fabricate monolithic (M) crowns. Zirconium dioxide copings were fabricated with inCoris ZI blocks in anatomic and non-anatomic designs and monolithic crowns were fabricated with inCoris TZI blocks using CEREC 4.2 CAD/CAM technology. They were then veneered with IPS e.max Ceram. Finally, they were glazed and cemented with Panavia F 2.0 onto metal dies. All crowns were subjected to thermal cycling (5-55 °C, 10.000 cycles) and 10.000 cycles of cycling loading with 1 Hz crosshead-speed and a load of 10-110 N. Subsequently, all specimens were loaded at an angle of 10?, until a fracture occurred in a universal testing machine (Shimadzu AG-IS 100). Failure types were examined with stereomicroscope. Scanning electron microscopy was used for further failure analyzing. The fracture load data were compared by a one-way analysis of variance test (ANOVA) at a significance level of 0.05. Mean fracture strength of groups were; CA=4456,82±1406,29 N; CN=3576,14±1092,44 N; SA=2598,37±660,346 N; SN=3154,26±1893,95 N; KA=3270,74±1294,81 N; KN=2666,48±1498,84 N; M=7582,25±1891,90 N. According to the results of the study chamfer group showed higher fracture strength than other groups (p0,05). According to the results of this in-vitro study, finish lines had significant effect on fracture strength (p0,05) and framework design did not significantly affect the fracture strength of the crowns (p>0,05).Çalışmamızın amacı farklı basamak ve alt yapıların zirkonya restorasyonların kırılma direncine etkisini incelemektir. Aynı zamanda çalışmamızda monolitik zirkonya restorasyonların da kırılma direnci incelenmiştir. Bu amaçla chamfer (C), shoulder (S) ve knife-edge (K) preparasyon tipleri uygulanarak 3 diş örneği hazırlandıktan sonra, her grup için 22 adet silikon ölçü alınmıştır. Bununla birlikte monolitik (M) zirkonya restorasyonların üretimi için chamfer grubundan 11 adet ölçü daha alınmıştır. Ölçüler döküm güdükleri elde etmek için kullanılmıştır. Anatomik ve non-anatomik zirkonya alt yapılar inCoris ZI blokları kullanılarak, monolitik restorasyonlar ise inCoris TZI bloklar kullanılarak CEREC 4.2 CAD/CAM sistemiyle üretilmiştir. Restorasyonlar tamamlandıktan sonra döküm güdüklere simante edilmiştir. Örneklere 5 - 55 °C derece aralığında 10.000 devir ısıl döngü işlemi ve 1 Hz frekansla 10-110 N arasında 10.000 devir siklik yükleme uygulanmıştır. Yaşlandırma prosedürlerinin ardından restorasyonlara universal test cihazında (Schimadzu) statik yükleme altında, 10° eğimle kırma testi uygulanmıştır. Grupların kırılma değerleri; CA=4456,82±1406,29 N; CN=3576,14±1092,44 N; SA=2598,37±660,346 N; SN=3154,26±1893,95 N; KA=3270,74±1294,81 N; KN=2666,48±1498,84 N; M=7582,25±1891,90 N bulunmuştur. Kırma testinin sonuçlarına göre, chamfer diş preparasyonu uygulanan grup istatistiksel açıdan anlamlı derecede yüksek kırılma değerlerini göstermiştir (p0,05). Çalışmanın sonucunda basamak tipinin restorasyonların kırılma direncini etkilediği bulunmuştur (p0,05). Alt yapı tasarımının ise restorasyonların kırılma direncini etkilemediği bulunmuştur (p>0,05

Directions and right-left perception in Turkish culture

Bu çalışma, Türklerin kültürel özelliklerini ve bu özelliklerin her bir parçasında yönlerin ve sağ-sol algısının etkilerini ele almaktadır. Evrenin nasıl yaratıldığını sorgulayan ve bu süreci mantıklı bir zemine oturtma arayışında olan Türkler, tarihi akış içinde kozmolojilerini şekillendirmişlerdir. Bu aşamada yönlerin diğer simgesel unsurlarla ilişkilerini ortaya koyarak bütüncül bir bakış açısı yakalamışlardır. Türk kozmolojisine hâkim olan evrenselci dikotomide, ayrıştırıcı değil bütünleyici yaklaşım söz konusudur. Gök ve yer birbirini tamamlayan iki unsur olarak değerlendirilmektedir. Şamanist dünya görüşünde ise üçlü evren telakkisi yer almaktadır. Gök ve yere kutsiyet atfedilirken yer altı, karanlık ve kötü ruhların egemenliği altında olduğu için kutsiyetten uzaktır. Türk kozmolojisinde evrenselci dikotomi ile üçlü evren anlayışı, yönlerin belirlenmesinde etkili olmaktadır. Evrenin dikey ve yatay modeli dört yön tasarımıyla algılanmaktadır. Yönlerin anlamlandırılmasında diğer ana etmen güneşin günlük ve yıllık hareketine dayanmaktadır. Evrenin dikey algılanışında; Tanrı makamı olarak düşünülen gök, kutsiyetin kaynağı olması bakımından (yukarı) kutsal, canlıların ve yer-subların olduğuna inanılan yeryüzü (orta) kutsal, kötü ruhların hakimiyet alanı olan yer altı (aşağı) ise kutsal dışı kabul edilmektedir. Evrenin yatay algılanışında yön tayini yaparken yüzünü güneşe yani doğuya dönerek yapan Türkler için sağ tarafta güney, sol tarafta kuzey yer almaktadır. Yönler; renk, hayvan, mevsim, zaman dilimi, element, gezegen gibi unsurlar ile ilişkilendirilmiştir. Bu simgesel unsurlarla birlikte yönlere yüklenen anlamlar, sağ-sol algısını beraberinde getirmektedir. Sağ-sol algısı günlük yaşamdaki hareketler üzerinde şekillendirici rol oynamaktadır. Çalışma iki bölümden oluşmaktadır. Çalışmanın birinci bölümünde Türk kozmolojisi, yönler ve yönlerin ilişkili olduğu unsurlar ele alınmış olup yön ve simgesel unsurların ilişkileri detaylı şekilde incelenmiştir. İkinci bölümde yönlerden hareketle sağ-sol algısının temelleri, ritüellere yansıma şekilleri ve siyasi yaşamdaki rollerine yer verilmiştir.This study deals with the cultural characteristics of Turks and the effects of directions and right-left perception in each part of these features. The Turks, who question how the universe was created and seek to put this process on a logical basis, have shaped their cosmology in the course of history. At this stage, they have captured a holistic perspective by revealing the relations of the directions with other symbolic elements. In the universalist dichotomy that dominates Turkish cosmology, there is an integrative approach rather than a divisive one. The sky and the earth are considered as two elements that complement each other. In the shamanist worldview, there is the concept of triple universe. While sanctity is attributed to the sky and the earth, the underground is far from holiness because it is under the rule of darkness and evil spirits. In Turkish cosmology, the universalist dichotomy and the triple universe understanding are effective in determining the directions. The vertical and horizontal model of the universe is perceived by its four-direction design. The other main factor in making sense of the directions is based on the daily and annual movement of the sun. In the vertical perception of the universe, the sky, which is thought to be the seat of God, is considered sacred in terms of being the source of holiness (upper), the earth (middle), which is believed to be the living things and earth-subs, is considered holy, and the underground (lower), which is the domain of evil spirits, is considered unholy. For Turks, who turn their faces to the sun, that is to the east, while determining the direction in the horizontal perception of the universe, south is on the right and north is on the left. directions. It is associated with elements such as color, animal, season, time zone, element, planet. Along with these symbolic elements, the meanings attributed to the directions bring along the perception of right-left. Right-left perception plays a shaping role on movements in daily life. The study consists of two parts. In the first part of the study, Turkish cosmology, aspects and the elements related to the aspects were discussed and the relations of the direction and symbolic elements were examined in detail. In the second part, the foundations of right-left perception, its reflection on rituals and its role in political life are given

The effect of big data in transforming to learning organization: a single-case study in IT sector

TARAMAWOSWOS:000758239600001TARAMASCOPUSAbstract Purpose The purpose of this paper is to examine the contribution of big data in the transforming process of an IT firm to a learning organization. Design/methodology/approach The authors adopted a qualitative research approach to define and interpret the ideas and experiences of the IT firms’ employees and to present them to the readers directly. For this purpose, they followed a single-case study design. They researched on a small and medium enterprise operating in the IT sector in Düzce province, Turkey. This paper used a semi-structured interview and document analysis as data collecting methods. In all, eight interviews were conducted with employees. Brochures and website of the organization were used as data sources for the document analysis. Findings As a result of in-depth interviews and document analysis, the authors formed five main themes that describe perception of big data and learning organization concepts, methods and practices adopted in transforming process, usage areas of big data in organization and how the sample organization uses big data as a learning organization. The findings of this paper show that the sample organization is a learning IT firm that has used big data in transforming to learning organization and in maintaining the learning culture. Research limitations/implications The findings contribute to literature as it is one of the first studies that examine the influence of big data on the transformation process of an IT firm to a learning organization. The findings reveal that IT firms benefit from the solutions of big data while learning. However, as the design of the research is single-case study, the findings may be specific to the sample organization. Future studies are required that examine the subject in different samples and by different research designs. Originality/value In literature, research on how IT firms’ managers and employees use big data in organizational learning process is limited. The authors expect that this paper will shed light on future research that examines the effect of big data on the learning process of the organization

Indocyanine green-loaded halloysite nanotubes as photothermal agents

Photothermal nanoparticles with light-to-heat conversion properties have gained interest in recent years and have been used in a variety of applications. Herein, indocyanine green (ICG), which is commonly employed as a photothermal agent suffering from low photostability, was loaded into halloysite nanotubes (HNTs) resulting in photothermal HNT-ICG nanohybrids. The photothermal heating patterns of the prepared photothermal nanohybrids as a result of near-infrared (NIR) irradiation were carefully examined. The nanohybrids reached a temperature of 216 °C in 2 min under NIR light, and in contrast to free NIR, the ICG loaded into HNTs remained stable over 10 heating and cooling cycles. Moreover, HNT-ICG nanohybrids incorporated into polyacrylonitrile (PAN) were electrospun into nanofibers for use as photothermal nanofibers, and composite nanofibers, which heat up to 79.3 °C under 2 min of NIR irradiation, were obtained. To demonstrate the potential of the PAN/HNT-ICG nanofibers as light-activated antibacterial nanofibers, their NIR light-activated killing activity on Staphylococcus aureus (S. aureus) cells has been explored. The composite nanofibers reduced the number of bacteria on their surface by 7log upon 10 min of NIR irradiation. Encapsulation of ICG in HNTs as a carrier has been demonstrated as an effective way to stabilize ICG and incorporate it into materials and coatings without compromising its functionality

Halloysite nanotube/polydopamine nanohybrids as clay-based photothermal agents for antibacterial applications

Nanoparticles with light-to-heat conversion properties play vital roles in the design of photothermal materials that can be remotely heated via light activation. Halloysite nanotubes (HNTs), versatile natural clay nanoparticles, were converted into efficient photothermal agents by functionalizing them with polydopamine, a polymer with light-to-heat conversion properties. By varying the polydopamine functionalization reaction conditions such as dopamine concentration, reaction time, and the nature of the HNTs, HNT-polydopamine (HNT-PDA) nanohybrids comprising different amounts of polydopamine were obtained. HNT-PDA nanohybrids presented significant temperature elevations when irradiated with 808 nm laser light, reaching 250 °C in 2 min, and were demonstrated to be effective photothermal agents, whose light-to-heat conversion properties and the degree of light-activated temperature elevations can be easily tuned by controlling the polydopamine content through reaction conditions. The photothermal effect of HNT-PDA nanohybrids was demonstrated to be stable over multiple laser light-activation cycles, allowing their reusability. In addition to infrared laser light activation, HNT-PDA nanohybrids were also shown to be activated by other light sources of more practical importance such as a solar simulator, an infrared incandescent lamp, and a light-emitting diode (LED) lamp, demonstrating their versatility as photothermal agents. As one of the potential applications of HNT-PDA nanohybrids, their light-activated antibacterial activity was evaluated. The viability of Staphylococcus aureus (S. aureus) treated with HNT-PDA nanohybrids was reduced by 6.3 log when irradiated with infrared laser light for 5 min, whereas bacteria not treated with the nanohybrids stayed alive under the same irradiation conditions. Comprising natural, nontoxic, cost-effective components, HNT-PDA nanohybrids are promising nanoparticles as versatile clay-based photothermal agents that can be utilized in various photo-driven applications