Background: This in vitro study measure and compare the effect of light curing tip distance on the depth of cure by measuring vickers microhardness value on two recently launched bulk fill resin based composites Tetric EvoCeram Bulk Fill and Surefil SDR Flow with 4 mm thickness in comparison to Filtek Z250 Universal Restorative with 2 mm thickness. In addition, measure and compare the bottom to top microhardness ratio with different light curing tip distances. Materials and Method: One hundred fifty composite specimens were obtained from two cylindrical plastic molds the first one for bulk fill composites (Tetric EvoCeram Bulk Fill and Surefil SDR Flow) with 4 mm diameter and 4 mm depth, the second one for Filtek Z250 Universal Restorative with 4 mm diameter and 2 mm depth. Each spcimen was light-cured using WOODPECKER LED CURING LIGHT for 20 sec. Polymerization was performed with the light tip positioned in direct contact, 2 mm, 4 mm, 6 mm and 8 mm distant from the top surface of the sample. After one day of storage in distilled water in a light proof container at 37ËšC, the hardness on the bottom and top surfaces of each specimen was tested using the Digital Micro Vickers Hardness Tester. Then the Data were analyzed statistically by ANOVA test, LSD test and t-test. Results: All experimental groups show top microhardness higher than bottom microhardness with high significant difference with all light tip distances. At 0 mm light tip distance all groups give the highest microhardness value. Filtek Z250 Universal Restorative shows accepted bottom to top microhardness ratio at all light tip distances. Surefil SDR Flow shows accepted bottom to top ratio only at 0, 2 and 4mm light tip distances while Tetric EvoCeram Bulk Fill shows the bottom to top microhardness ratio less than the accepted value with all light tip distances. Conclusion: From the results of this study we can conclude that the polymerization of bulk fill composite depends greatly on the distance from light curing tip, Tetric EvoCeram Bulk Fill composite not recommended to be used as bulk fill restoration in deep cavities and need further studies, while Surefil SDR Flow not recommended to be used in deep cavity when curing tip distance (6-8 mm), in addition we can conclude that the thickness of the increments is more important than light curing tip distance.
The development of the perforated fin had proposed in many studies to enhance the heat transfer from electronic pieces. This paper presents a novel derivative method to find the temperature distribution of the new design (inclined perforated) of the pin fin. Perforated with rectangular section and different angles of inclination was considered. Signum Function is used for modeling the variable heat transfer area. Set of parameters to handle the conduction and convection area were calculated. Degenerate Hypergeometric Equation (DHE) was used for modeling the Complex energy differential equation and then solved by Kummer’s series. In the validation process, Ansys 16.0-Steady State Thermal was used. Two geometric models were consider
... Show MoreThe Semitic Languages have her its Articulatory That what we attend to discuss In this Research to Represent the Relation Between them and the Light Of Semitics a Comparative Studies where ever It's Exists The Semitic languages by comparing the words whish most Semitic languages share with each other. We call such Words the Semitic denominator. We have adopted a comparative framework in our Research, which is based on comparing an Arabic word with its Semitic counterpart in Order to identify the forms that control grammatical change in both language
... Show MoreIn The Name of Allah Most Gracious Most Merciful
In this research, I will deal with the significance of the imperative and the disagreement of the fundamentalists in the general requirement by dividing it into an introduction and two sections. , and the appropriate indication.
الخلاصة لقد شكل المحافظون الجدد وهم بالأساس نخبة من المثقفين ومن السياسيين الأمريكيين كتلة ضغط كبيرة التأثير على الإدارة في عهد الجمهوريين. حمل هؤلاء المحافظون مشروعاً إيديولوجياً البسوه لسلطة الجمهوريين وهو يهدف إلى جعل أمريكا سيدة العالم من دون منازع خاصة بعد انهيار الاتحاد السوفييتي ونهاية الحرب الباردة. واكب هذا الحدث التاريخي الكثير من الأفكار ومنها (نهاية التاريخ)، وصراع الحضارات، وكذ
... Show MoreDrama is one of the means of transmitting human experiences, as it presents within it the life ideas and visions of the spectator, who is subject to their influence on him, robbed of the will in front of its charm and various display arts, which invade him with its dimensions and affect his references, and this art form is based on stories revolving around personalities involved in events that have grown As a result of the struggle of two conflicting opponents, or two opposing forces or emotions generated as a result of a voluntary conflict, as this dramatic conflict represents the most important elements of those events, as it is embodied in an inevitable scene that emerges from other scenes, and this scene is sometimes subject to the
... Show MoreSince his first existence on earth, human had formed a connecting link for a regressive, kinetic and developed relationship that comes from a semi-complicated interaction between natural environment and constructed environment, and this resulted in the survival of human and his existence continuance. Constructed environment enabled human to survive the natural environment inconstancies and enemies as predators, also it helped him to feel safe, comfortable and to practice his everyday life activities...etc. This alternative interaction resulted in creating a civilized legacy for a group of landmarks that tell about the development of this relationship by elemental output that reached us either by documents and manuscripts or as an existed
... Show MoreThe media: ((Providing people with the right news, audio information, and constant facts that help them form a correct opinion in an incident or a problem, this opinion gives an objective expression of the mentality of the audience, their trends and tendencies). The German scientist Autogroot defines it as "the objective expression of the mentality of the audience, their spirit, their tendencies, and their trends at the same time." Whereas for "Aristotle", (Language) is a specific verbal system created as a result of an agreement between the members of the human group somewhere )). It is a symbol of thought, and a difference between humans and animals. Pronunciation and thought for “Aristotle” are intertwined: without pro
... Show Moreدور اللوبي الصهيوني في صنع السياسة الأمريكية
After more than ten years of successful march of the European single currency and EU countries faced a crisis in one of its debt, which recently joined the monetary union is not Greece . Perhaps mpre than th effects of this crisis, the fact that its consequences were not confined to Greece alone , but expand it to include all EU countries in general and the countries of the European Monetary Union in particular.
Sine the debt crisis that emerged Greek and talk a lot a bout their effects on the global economy and the potential harm done th the situation of the global economy recovers from the global financial crisis (mortgage crisis), or delayed and also the fears of other crises to other member states suf
... Show MorePoor impurity in the right of the patient and the elderly