objective: diagnosis of vertical root fractures (vrfs) is critical in endodontics. cone beam computed tomography (cbct)  has significantly enhanced image quality compared to digital radiography (dr) and greatly aids the diagnosis of vrfs but, metal artifacts has remained as a problem in vrf detection.  this study evaluated the effect of intra canal posts on the diagnostic accuracy of cbct and d...

introduction: due to the importance of apical transportation during root canal preparation, the aim of the current study was to use cone-beam computed tomography (cbct) to assess the extent of apical transportation caused by protaper and mtwo files. methods and materials: forty extracted maxillary first molars with 19-22 mm length and 20-40 degrees of curvature were selected. the mesiobuccal ca...

introduction : the aim of this in vitro study was to compare the effect of gates-glidden and peeso reamer drills on residual dentin thickness during post space preparation in order to discover which method has minimum root structure damage. materials and methods: thirty extracted human maxillary premolars with bifurcations at root middle were horizontally cut 15 mm coronal to the apical end aft...

introduction: the purpose of this clinical study was to compare the accuracy of working length (wl) determination using cone-beam computed tomography (cbct), conventional periapical radiographies and electronic apex locator. methods and materials: this study was conducted during root canal treatment of 19 patients with a total of 30 single-rooted teeth diagnosed with apical periodontitis. after...

Among the intermolecular interactions, the Casimir and van der Waals forces are the most important forces that highly affect the behavior of nanostructures. This paper studies the effect of such forces on the adhesion of cantilever freestanding nanostructures. The nanostructures are made of a freestanding nano-beam which is suspended between two upper and lower conductive surfaces. The linear s...

In this paper, we investigate the effects of auto-tracking subsystem together with different beam divergences on SNR, BER and stability of FSO communication links. For this purpose we compute the values of power, SNR and BER on receiver, based on analytic formula of Gaussian beam on receiver plane. In this computation the atmospheric effects including absorption, scattering and turbulence are c...

resorption of tooth structures can occur as a result of physiological, pathological, and idiopathic factors. early diagnosis and appropriate treatment can prevent its serious complications. this case report presents surgical endodontic management of a trauma-induced perforating external root resorption, which was diagnosed with the help of cone beam computed tomography. following root canal tre...