background and aims. determining the proper length of the root canals is essential for successful endodontic treatment. the purpose of this in vitro study was to evaluate the effect of file size on the accuracy of the raypex 5 electronic apex locator for working length determination of uninstrumented canals. materials and methods. twenty maxillary central incisors with single straight canals we...

introduction: this article describes the diagnosis and treatment of two symmetrical maxillary first molars with two canals in their distobuccal roots. a 32-year-old female had an emergency treatment because of the pain in tooth #16. on the second visit after accessing the pulp chamber and detecting three major canals (mb, db, and p) and exploring the 4th canal (mb 2 ), we noted that there was a...

The lactose permease of Escherichia coli (LacY), a dynamic polytopic membrane protein, catalyzes galactoside-H+ symport and operates by an alternating access mechanism that exhibits multiple conformations, the distribution of which is altered by sugar binding. We have developed single-domain camelid nanobodies (Nbs) against a mutant in an outward (periplasmic)-open conformation to stabilize thi...

An immature permanent mandibular central incisor with periapical involvement in a 7-year-old boy was treated to promote revascularization. The tooth suffered from acute apical periodontitis after periodontal treatment by a general practitioner. An access cavity was prepared in the tooth and the cavity was left open until the next visit to achieve drainage through the canal. The root canal was n...

X-ray crystal structures of LacY (lactose permease of Escherichia coli) exhibit a large cytoplasmic cavity containing the residues involved in sugar binding and H(+) translocation at the apex and a tightly packed side facing the periplasm. However, biochemical and biophysical evidence provide a strong indication that a hydrophilic pathway opens on the external surface of LacY with closing of th...

OBJECTIVES To shed light on the endoscopic anatomy of the middle ear seen on 2-port endoscopy and to describe potential clinical applications. DESIGN Anatomical structures were visualized by transmeatal or transtympanic rigid scopes of different angles and by a flexible scope in the eustachian tube. This arrangement ensured reciprocal guidance of the scopes and provided access to regions not ...

INTRODUCTION The conventional method of teaching endodontics has some drawbacks. Due to the small size of the oral cavity, students cannot closely observe the clinical procedure. Use of new teaching modalities such as the intraoral camera may obviate this problem. This study assessed the effect of video-assisted clinical instruction in dentistry (VACID) on dental student's knowledge and perform...

abstract : before initiating any endodontic therapy, probability of extra canals should be considered. the incidence of three canals in mandibular second premolar has been reported to be 0.46-0.5%. the present report describes nonsurgical endodontic treatment of three mandibular second premolars with three canals. in these cases, three orifices were located in mesiobuccal, distobuccal and lingu...

Background: Understanding some part of the human body such as serous membrane, peritoneal cavity, lesser sac and proper mesentery is difficult for medical students. The objective of this study was to determine the effect of animal dissection on improving medical student knowledge and view related viscera and serous membrane anatomy. Methods: In YUMS in 2011, sixty eight medical students were ra...