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, ...

introduction: the aim of this in vitro study was to compare the canal transportation of two single-file engine-driven systems, neoniti and reciproc, using cone-beam computed tomography (cbct). methods and materials: forty-five non-calcified roots with mature apices and apical curvature of 15-30 degrees were selected from extracted human maxillary molars for this study. samples were randomly div...

introduction: apical transportation changes the physical shape and physiologic environment of the root canal terminus. the aim of the present experimental study was to determine the extent of apical transportation after instrumentation with hand k-flexofile and k3 rotary instruments by means of cone-beam computed tomography (cbct). methods and materials: forty mesiobuccal root canals of maxilla...

introduction: the aim of this study was to identify the root and canal morphology of maxillary first and second molars in iranian population by taking and analyzing cone-beam computed tomography (cbct) scans. methods and materials: extracted maxillary first ( n =125) and second ( n =125) molars were collected from native iranians and scanned by using a cbct scanner. the number of roots and conf...

As a potentially important technology for medical x-ray computed tomography (CT), lambda tomography (LT) is to reconstruct a gradient-like image only from local projection data. Based on our recently derived exact fan-beam LT formula, [H. Y. Gu and G. Wang, Int. J. Biomed. Imaging 2006(1), 1-9 (2006)] here we propose a practical cone-beam LT algorithm for LT reconstruction from local data colle...

A cone beam computed tomography (CBCT) scanner integrated with a linear accelerator is a powerful tool for image guided radiotherapy. Respiratory motion, however, induces artifacts in CBCT, while the respiratory correlated procedures, developed to reduce motion artifacts in axial and helical CT are not suitable for such CBCT scanners. We have developed an alternative respiratory correlated proc...

In the flat panel detector-based cone beam CT system, the scatter photons which reach the flat panel detector increase the detected signal, produce the image cupping artifact and reduce the image contrast. To conquer the X-Ray scatter problem, this study proposes the beam attenuation grid -based scatter correction algorithm that needs to add a beam attenuation grid (BAG) between the X-Ray sourc...

We propose a new fast Feldkamp algorithm for 3-D cone beam tomography with a circular source trajectory. The algorithm is an extension of our recent fast native 2-D fan-beam reconstruction algorithm. It is based on a recursive hierarchical decomposition of the cone-beam backprojection operation into successively smaller sub-volumes. The algorithm reduces the computational complexity of the reco...

Abstract In this paper, for the first time we define the concept of 3D pseudo-lambda tomography based on the 3D Calderon operator, and formulate an approximate local reconstruction algorithm for cone-beam data collected along an arbitrary scanning curve. The main idea is to rewrite the filtering operator in an exact filtered-backprojection reconstruction formula as a local projection. Simulatio...

Cone beam computed tomography (CBCT) is the modern third dimension applied in the field of oral maxillofacial region. With lower radiation dose compared to conventional CT, its applications in dentistry has increased tremendously. Artefacts can seriously degrade the quality of computed tomographic (CBCT) images, sometimes to the point of making them diagnostically unusable. To optimize image qu...