introduction: to investigate the ultrastructural changes of dentin irradiated with 980-nm diode laser under different parameters and to observe the morphological alterations of odontoblasts and pulp tissue to determine the safety parameters of 980-nm diode laser in the treatment of dentin hypersensitivity (dh). methods: twenty extracted human third molars were selected to prepare dentin discs. ...

introduction: endodontic k-files are major tools for cleaning and shaping of the root canal systems. as there are various k-files available in iranian market, the physical properties of the five available brands were investigated to assist the clinician when selecting suitable endodontic k-files according to the intended application. materials and methods: physical properties (including debris ...

A scanning tunneling microscope (STM) equipped with a field ion microscope (FIM) which operates at room temperature has been constructed and operated successfully to obtain atomically resolved STM images with 100% reproducibility. This instrument, which we call the FI-STM, has been employed for the quantitative study of the Si(100) "2xn" phase.

introduction the aim of this study was to compare the smear layer removal efficacies of 3% sodium hypochlorite (naocl), 17% ethylenediaminetetraacetic acid (edta), smearclear and biopure mtad using a common irrigation protocol. materials and methods: fifty freshly extracted human single rooted maxillary and mandibular teeth were prepared by a protaper rotary system up to an apical preparation f...

this study compared the marginal adaptation of mineral trioxide aggregate (mta) and mta-like materials as root-end fillings after incubation in phosphate buffer saline (pbs), a synthetic tissue fluid, for either 1 week or 2 months.in this experimental study, seventy-two extracted human single-rooted teeth were prepared and obturated with gutta-percha and ah26 sealer. the apical 3 mm of the root...

introdouction: dentinal hypersensitivity (dh) is one of the most painful chronic problems reported in dental offices. various methods have been applied for the treatment of dh. however, majority of them are either ineffective or last for a short period of time. it has been reported that lasers, particularly neodymium- doped: yttrium aluminum garnet laser (nd: yag), can be helpful in the treatme...

while a wide array of pathological changes occur in cerebral arteries following subarachnoid hemorrhage (sah), the most consistent is endothelial damage. since the endothelium normally modulates reflexes that influence vascular tone, any damage to it may represent a significant contributor to cerebral vasospasm following sah. this experimental study investigates the correlation between endothel...

A first-principles theory of inelastic tunneling between a model probe tip and an atom adsorbed on a surface is presented, extending the elastic tunneling theory of Tersoff and Hamann. The inelastic current is proportional to the change in the local density of states at the center of the tip due to the addition of the adsorbate. We use the theory to investigate the vibrational heating of an ads...

introduction: today, have been approved scientifically relationship between presence of asbestos fibers in the human respiratory area and malignant diseases such as lung advanced fibrosis (asbestosis), gastrointestinal, lung and laryngeal cancers. the aim of this study was the determination of asbestos fibers concentration in yazd city’s air in the summer of 2015. methods: this is a descriptive...

We studied the influence of a magnetic field (MF) on epitaxial growth and properties Fe(001) films deposited MgO(001). Thanks to modular sample holders specialized manipulator in our multi-chamber ultrahigh vacuum system, could be annealed an in-plane MF 100 mT. In situ scanning tunnelling microscopy showed that had strong film morphology, and, particular, structure surface steps. The were ex u...