introduction: objective: this study aimed to assess the possible variations in root canal anatomy and topography of the apices of first and second maxillary molars. materials and methods: a total of 67 first and second maxillary permanent molars were collected. access cavity was prepared and 2% methylene blue was injected. the teeth were demineralized by 5% nitric acid and cleared with methyl s...

We present a comparison of three neural PCA techniques: the GHA by Sanger, the APEX by Kung and Diamataras, and the { APEX rst proposed by the present authors. Through numerical simulations and computational complexity evaluations we show the {APEX algorithms exhibit superior capability and interesting features.

BACKGROUND Cerebral saccular aneurysm is a major cause of subarachnoid hemorrhage, one of the cerebrovascular diseases with the highest mortality. The mechanisms underlying the development of aneurysms, however, still remain unclear. We have made a series of reports on an animal model of experimentally induced cerebral aneurysms that resemble human cerebral aneurysms in their location and morph...

This paper describes attempts to localize the site of perception of low temperatures (0-10 degrees C) during thermoinduction in Thlaspi arvense L. Reproductive development (stem elongation and flower formation) was observed when shoots were cooled to 4 degrees C for 4 weeks and then returned to 21 degrees C while maintaining the roots constant 21 degrees C. However, chilling the roots was ineff...

It is a worthy aim to preserve the pulp vitality in teeth with immature root in order to continue the root's maturation. Traumatic injuries and caries are two main reasons for pulp exposure in immature teeth. This article describes two vital pulp therapies on two patients, a nine-year-old boy with traumatized central tooth and a 10-year-old boy with caries exposure in a premolar tooth. Both tee...

The gradient and dynamic flow of the plant growth regulator auxin (indole-3-acetic acid [IAA]) in shoot and root apices is thought to be a critical factor in determining meristematic activity (i.e., the maintenance of stem cell niches and the regulated development of organ primordia) (reviewed in Leyser, 2006; Tanaka et al., 2006). Therefore, determining the precise role of auxin and its regula...

petrous apex lesions of temporal bone progress slowly. most of the time not only destruct this area but also involve neighbouring element. the symptoms of the neighbouring neuro-vasculare involvement we can recognize these lesions. the most common symptoms of involvement of the petrous apex are: headache, conductive hearing loss or sensorineural type, paresthesia and anesthesia of the trigemina...

introduction: success in endodontic treatment depends on various factors. among the most important factors, appropriate preparation of the root canal system and keeping periapical region intact as much as possible could be mentioned. these are achieved by determining the penetration depth of the instruments into the canal i.e. the working length. several methods are introduced for working lengt...

introduction: the aim of this study was to gather information on the materials and methods employed in root canal treatment (rct) by general dental practitioners (gdps) in iran. methods and materials: a questionnaire was distributed among 450 dentists who attended the 53 th iranian dental association congress. participants were asked to consider demographic variables and answer the questions re...

introduction: despite being the gold standard as well as a routine technique in endodontics, radiographic working length (wl) determination owns many drawbacks. electronic apex-locators (eals) are recommended to complement radiographies. the aim of this study was to evaluate the perceptions of iranian general dental practitioners (gdps) towards using radiography and eal. methods and materials: ...