a healthy female was referred to endodontic department. the referral letter from her dentist expressed that an emergency pulpotomy of tooth #27 had been carried out with probable perforation of the chamber floor which was due to the unusual anatomy of the chamber. cone-beam computed tomography (cbct) revealed that the tooth had two mesial and two distal canals. perforation site was repaired and...

introduction : to achieve success in treatment, one cannot ignore the knowledge of pulp anatomy. mandibular premolars are considered to be the most difficult teeth for endodontic therapy due to high variability in their canal morphology. it is possible that a relation exists between the crown size and the number of extra canals in these teeth, so this in vitro study aims to investigate the rela...

objectives: the purpose of this study was to determine buccal bone and soft tissue thicknesses and their correlation in the maxillary anterior region using cone beam computed tomography (cbct). materials and methods: in this cross sectional study, 330 sound maxillary incisors in 60 patients with a mean age of 37.5 years were assessed by cbct scans. for better visualization of soft tissue, patie...

In this paper at first introduced constituent equations for piezoelectric and then by the help of this equations, internal energy of hinged-hinged piezoelectric multilayer beam was computed. Then by the principle of minimum potential energy and Rayleigh -Ritz method the bending curvature equation of hinged-hinged piezoelectric multilayer beam under concentrated moment, concentrated force, unifo...

Gyroscopes are used as rotation rate sensors. Conventional gyroscopes are heavy and bulky, which creates important problems regarding their usage in different applications. Micro-gyroscopes have solved these problems due to their small size. The beam micro-gyroscope is one of the popular types of inertial sensors. Their small dimensions and low energy consumption are key reasons for their popul...

background marketing new radiography devices necessitates documenting their absorbed x-ray doses. since the current literature lacks studies on new devices, we assessed the doses of two new devices that had not previously been assessed. objectives the new devices were compared to the promax three dimensional (3d) scanner at two fields of view (fov) in nine critical head and neck tissues and org...

introduction: the purpose of this study was to investigate the root and canal morphology of maxillary first molars with regards to patients’ age and gender with cone-beam computed tomography (cbct). methods and materials: a total of 149 cbct scans from 92 (67.1%) female and 57 (31.3%) male patients with mean age of 40.5 years were evaluated. tooth length, presence of root fusion, number of the ...

introduction: this study sought to assess the effects of amperage (ma) and field of view (fov) on intracanal metal post artifacts and the diagnostic parameters for detection of vertical root fracture (vrf) in teeth with intracanal posts. methods and materials: in this diagnostic study, 80 human single-canal teeth were evaluated by cone-beam computed tomography (cbct). nickel chrome cast posts w...

one of the main causes of endodontic treatment failure is the clinician’s inability to localize all the root canals. due to the complex anatomy of the root canal system, missed canals are not uncommon. there are several strategies to decrease the possibility of missed root canals starting with good pre-operative radiographies. in order to overcome the limitations of conventional radiographies, ...