The goals of endodontic preparation were to shape and clean the space of the root canal and remove microorganisms, affected dentin and pulp, the apical foramen and the canal curve should be protected from being transported during endodontic canal preparation. The aim of this study was to evaluate the curve straightening of curved root canals and apical transportation after preparation with four rotary systems. Forty mesial roots of the lower 1st molars teeth only the mesiobuccal canals were used, these roots were immersed into cold clear acrylic , the teeth roots divided into four groups according to rotary system used for preparation of the canals (ten roots for each group):. group I: ProTaper Next rotary system, group II: IRaCe Plus rotar

This study evaluated the extent to which obturation materials bypass fractured endodontic instruments positioned in the middle and apical thirds of severely curved simulated root canals using different obturation techniques. Sixty resin blocks with simulated root canals were used, each with a 50° curvature, a 6.5 mm radius of curvature, and a length of 16.5 mm, prepared to an ISO #15 diameter and taper. Canals were shaped using ProTaper Universal files (Dentsply Maillefer) attached to an X-smart Plus endo motor (Dentsply), set at 3.5 Ncm torque and 250 rpm, up to size S2 at working length. To simulate fractures, F2 and F3 files were weakened 3 mm from the tip, then twisted to break in the apical and middle sections of the canal, re

Background: The purpose of this study is to compare the color changes between the bonded middle third and the unbonded gingival and incisal thirds, fallowing fixed orthodontic treatment Material and method: The color parameter l, a, b has been recorded for each thirds in upper anterior teeth by mean of easy shad device. The has been calculated for gingival, middle and incisal thirds for the upper anterior teeth in 34 patient, 17 males and 17femals, those subject undergone fixed orthodontic treatment Results: The in middle bonded third is highly significant higher than that in incise and gingival thirds p<0.01 because the middle third isn’t expose to oral fluid and dental brushing since it covered by the bracket. Also there

تعيش قارة آسيا حالة فريدة تكاد تقترب من حالة أوروبا قبل الحرب العالمية الثانية، فالقارة حاليا تحتوي على العديد من القوى الإقليمية الفاعلة أبرزها الصين وروسيا والهند واليابان، أما القوى الإقليمية الفاعلة في نطاق نظمها الإقليمية الفرعية نجد من أهمها الكوريتين (الشمالية والجنوبية)، وباكستان، وإيران وغيرها، ووجه الاختلاف عن أوروبا هو أن آسيا منطقة شاسعة جغرافياً، وكل نظام إقليمي فرعي فيها هو نظام قاري بحد ذات

Abstract

Through this study, I tried to identify the grammatical efforts of one of the most important authors of the footnotes that were built on the luminous benefits marked with (Explanation of Mulla Jami in Grammar), and he is Sheikh Isamah Allah Al-Bukhari, who died in the eleventh century AH, trying as much as possible to stay away from the path of tradition in repeating the efforts of Those who preceded me in explaining the grammatical efforts of many grammarians, and perhaps what helped me in this is the characteristics that characterize the notes owners that may distinguish them from other owners of grammatical authorship, as a result of what characterized the personality of the notes owners from the predominance of the in

تعد الحروب أحد أخطر التهديدات في النظام العالمي; فهي تعد خرقا للقوانين والاعراف الدولية، والمبادئ الإنسانية، و من هنا تأتي دراسة أهمية موضوعنا الموسوم بـ (الاحتمالات المستقبلية للحرب الروسية – الأوكرانية و مدى انعكاسها على أمن دول شرق أوربا بعد العام 2022 ،)اذ يرتكز هذا البحث على دراسة واستعراض الاحتمالات المستقبلية )السيناريوهات) للحرب الروسية – الأوكرانية، والتي شنت من الحكومة الروسية بقيادة الرئيس الروس

Photorefractive keratectomy (PRK) is the refractive technique that began with a physical scraping of the epithelial layer of cornea subsequent by laser treatment. Post this procedure to about 48 hours the removed epithelial layer regenerated to protect the eye again. The regeneration process (called re-epithelization) started from the limbus of the cornea toward the central part of it. The re-epithelization mechanism consists of a change in cell density (mitosis) and cell concentration (migration) with a velocity in two directions: radial and tangential. In the present study, an estimation for both radial (responsible for the overlapped layers toward the outward direction of the cornea) and tangential comp

In the postmodern era, the graphic design styles showed a new visualization method when the graphic designers had changed the traditional conditions by using design elements with new technics for photos, collage and comics illustration. The researcher assumes that the graphic design styles were affected by the art's movement at that period throw the same perspective of view for the concept presented in the art pieces and their entire message. Therefore, the researcher chooses field was the period of 1945-1970 in the USA for the (pop-art and conceptual-art) and explored the main visual effects that expressed the visual dialogue and compared them with the most common design styles ant the same period and location, the results of selected e

The COVID-19 pandemic has profoundly affected the healthcare sector and the productivity of medical staff and doctors. This study employs machine learning to analyze the post-COVID-19 impact on the productivity of medical staff and doctors across various specialties. A cross-sectional study was conducted on 960 participants from different specialties between June 1, 2022, and April 5, 2023. The study collected demographic data, including age, gender, and socioeconomic status, as well as information on participants' sleeping habits and any COVID-19 complications they experienced. The findings indicate a significant decline in the productivity of medical staff and doctors, with an average reduction of 23% during the post-COVID-19 period. T