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Evaluation of the effects of different surface treatments on the translucency and color stability of monolithic ceramic systems after accelerated aging
No full textBu çalışmanın amacı; farklı yüzey işlemleri uygulanmış monolitik seramik sistemlerde eskitme sonrası renk ve translusensi değişimlerini değerlendirmektir. Monolitik zirkonya (Zirkonzahn Prettau) ve lityum disilikat seramik (IPS e.max Press LT) materyallerinden disk şeklinde örnekler hazırlanmıştır. Örnekler yüzey işlemine göre üç alt gruba ayrılmıştır (n=9, G grubu: glaze, L grubu: polisaj kiti ve P grubu: polisaj kitini takiben polisaj patı). Renk ölçümleri, UV eskitme işlemi öncesi ve sonrasında spektrofotometre cihazı (Vita Easyshade Advance 4.0, Vita Zahnfabrik, Bad Säckingen, Almanya) ile gerçekleştirilmiştir. L*, a*, b*, parametreleri kaydedilerek ΔE ve TP (Translusensi Parametresi) değerleri hesaplanmıştır. Veriler; Mann Whitney U, Kruskal Wallis ve post-hoc testler ile analiz edilmiştir (pL, G). IPS e.max Press materyalinde gerçekleşen renk değişimi ise uygulanan yüzey işlemlerinden etkilenmemiştir. IPS e.max Press materyali; Zirkonzahn Prettau materyalinden çok daha translusent bulunmuştur. İki materyal grubunda da uygulanan yüzey işlemleri arasında TP değerleri açısından istatistik olarak anlamlı farklılık görülmemiştir. Eskitme sonrası translusensi değerleri iki materyal grubunda düşmüştür ancak bu düşüş klinik olarak algılanabilir seviyenin çok altındadır. Yüksek estetik gereksinimin mevcut olduğu ön bölge restorasyonlarında monolitik zirkonya yerine, lityum disilikat seramik materyalinin daha iyi bir tercih olacağı düşünülmektedir.The aim of this study was to evaluate the influence of surface treatments and aging procedures on the translucency and color stability of monolithic ceramic systems. Disc-shaped specimens for each material; monolithic zirconia (Zirkonzahn Prettau) and lithium disilicate monolithic glass-ceramic (IPS e.max Press LT) were prepared according to the manufacturer's instructions. The specimens were divided into three groups according to the surface treatments (n=9, Group G:Glazing, Group L: Rubber polishing system and Group P: Rubber polishing system followed by polishing paste.) Color measurements were performed before and after UV aging process, using a spectrophotometer device (Vita Easyshade Advance 4.0, Vita Zahnfabrik, Bad Säckingen,Germany). L*, a*, b*, parameters were recorded and ΔE and TP (Translucency Parameter) values were calculated. Data were statistically analysed using Mann Whitney U, Kruskal-Wallis and post-hoc tests (pL, G). Color change value was not affected by the surface treatment for the IPS e.max Press after aging. IPS e.max Press showed significantly greater translucency than Zirkonzahn Prettau material. There were no significant differences in TP values between the surface treatments applied to the two groups of materials. TP values of both material groups decreased after aging but these changes were not clinically perceptible. Lithium disilicate glass ceramic considered to be a better choice than monolithic zirconia for the restorations in the anterior region which highly esthetic requirements are demanded
Hıstopathologıc Evaluatıon Of Rat Connectıve Tıssue Response to Dıfferent Self Adhesıve Cements
No full textSelf adeziv simanlar, estetik, mekanik ve uygulama kolaylığı gibi bir çok olumlu
özelliğinden dolayı, tam seramik sistemlerin simantasyonunda sıklıkla tercih edilen
simanlardır. Biyouyumluluk, bir materyalin uygulandığı bölgede uygun biyolojik cevabı
oluşturabilmesidir. Bu çalışmanın amacı, 3 farklı self adeziv rezin yapıştırma simanına
(High Q Bond SE, Zirconite, Panavia SA) ait subkutanöz doku cevabının histopatolojik
olarak değerlendirilmesi ve karşılaştırılmasıdır. Çalışmada 3 farklı siman grubu ve bir de
kontrol grubu olmak üzere 4 grup oluşturuldu (n:7). Polietilen tüplere yerleştirilen örnekler
ve boş polietilen tüpler (kontrol grubu) 21 adet Wistar Albino ratın dorsal subkutanöz
dokusuna yerleştirildi. İmplantasyon işleminden 7, 30 ve 90 gün sonra örnekler çıkarılarak
histopatolojik değerlendirme yapıldı. Yerleştirilen her bir örneğe bitişik dokudaki fibröz
kapsül kalınlığı ve enflamatuar hücre sayıları değerlendirildi. 7. günde tüm gruplarda
enflamatuar hücre sayıları ve kapsül kalınlığı yüksekti ve şiddetli enflamatuar reaksiyon
saptandı. 30. günde tüm materyallerde orta şiddette enflamasyon gözlemlendi. 90. günde
tüm materyallerde enflamatuar hücre sayıları ve kapsül kalınlıkları azaldı. Panavia SA
siman grubunda orta şiddette enflamatuar reaksiyon gözlenirken, diğer gruplarda hafif
düzeyde enflamatuar reaksiyon belirlendi.Self adhesive resin cements have been frequently preferred for the cementation of allceramic
restorations because of their properties such as esthetics, mechanical advantage
and ease of applications. Biocompatibility is the appropriate biological response where the
material applicated. The purpose of the present study is to histopatologically evaluate and
compare the subcutaneus tissue response of three different self adhesive resin luting
cements (High Q Bond SE, Zirconite, Panavia SA Cement). In the present study, four
groups were generated as three different cement and control groups (n=7). Polyethylene
tubes which the specimens inserted and the empty polyethylene tubes were inserted into
the dorsal subqutaneous tissues of 21 wistar albino rats. The specimens were excised from
the rat connective tissue after 7, 30 and 90 days and histopathologically assessed. The
presence of inflammatory cells, and the thickness of fibrous connective tissue adjacent to
each inserted sample were evaluated. The number of inflammatory cells and the capsule
thickness were found to be high in all groups at 7 days and severe inflammatory reaction
were observed. At 30 days moderate inflammatory reaction was observed in all materials.
At 90 days the number of inflammatory cells and the thickness of the capsule were
decreased. Moderate inflammatory reaction was seen in Panavia SA cement while mild
inflammatory reaction was observed in the other groups
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Evaluation of the biocompatibility of various self-adhesive resin cements on subcutaneous connective tissue: An in vivo study
Get PDFBackground: The purpose of the study was to examine the subcutaneous connective tissue reaction to three self-adhesive resin cements.
Methods: Sixty-three polyethylene tubes were filled with three different self-adhesive resin cements (Group Z [Zirconite], Group P [Panavia SA], and Group H [High Q Bond]). Twenty-one polyethylene tubes remained empty and were used as controls (Group C). All tubes were implanted into the subcutaneous tissue of the 21 rats. Specimens from each cement type were obtained at 7, 30, and 90 days. Quantitative assessments of inflammatory cells were performed in 5 different areas of each specimen.
Results: All animals survive during the follow-up periods except two rats. The mean values of inflammatory cells at 90 days were 14 (±1.8), 15.1 (±3.5), 96 (±12.1), 16 (±2.1) in Groups C, H, P, and Z, respectively. The thicknesses of the fibrous capsule decreased significantly with time in all groups except Group P.
Conclusion: Biocompatibility of self-adhesive resin cements was material-dependent. High Q Bond and Zirconite exhibited satisfactory biocompatibility; however, Panavia demonstrated a moderate inflammatory response at 90 days
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
İLERİ SEVİYEDE REZORBE KRETLERE SAHİP TAM DİŞSİZ HASTANIN BAR TUTUCULU OVERDENTURE PROTEZLE REHABİLİTASYONU- OLGU SUNUMU
No full textAppropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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