objectives: the purpose of this study was to evaluate the resistance to fatigue failure of five different nickel-titanium rotary files in three different curved trajectories. materials and methods: a total of 150 neoniti a1, race 25.06, mtwo 25.06, twisted file 25.06 and protaper next x2 files with the tip size of 25 were tested (n=30 for each group). three groove types simulating curved canals...

introduction: marginal seal integrity is important for a successful adhesive dental restoration. alterations caused by laser irradiation in the enamel and dentin surface can affect the marginal integrity of adhesive restorations. the aim of this study was to evaluate the microleakage of a composite resin restoration in primary teeth following laser irradiation of enamel and dentin. methods: for...

objective: lack of a dental material with optimal adhesion and sealability is an important challenge in modern dentistry leading to marginal leakage. there are controversies on the necessity of enamel preparation in pit and fissure sealant therapy and its effect on decreasing the microleakage therefore, the present in vitro study aimed to assess the amount of microleakage with and without ename...

Functionalized polymeric microspheres based on a modifed polyether ether keetone (PEEK-WC) using immersion precipitation techniques were successfully prepared by doping initial polymeric solutions with DEHPA. The viscosity of the doping solution was measured for determining the optimal value for obtaining reproducible capsules. The modifed microspheres were characterize...

The possibility of using water insoluble fraction from biomass pyrolysis oil as additive in synthesis of Wood-Plastic novolac has been proved by using Differential Scanning Calorimetry (DSC) and Fourier Transformed Infra Red (FT-IR) spectroscopy. Synthesis of novolac with different concentrations (10, 20 and 30 wt %) of water insoluble fraction were performed. It was found that mechanical p...

introduction: the aim of this study was to evaluate the amount of dentine removed after canal preparation using stainless steel (ss) hand instruments or rotary profile instruments. materials and methods: thirty-six extracted human teeth with root canal curvatures less than 30º were embedded in clear polyester resin. the roots were cut horizontally at apical 2, 4 and 7 mm. dentin thickness was m...

introduction: this study compared the cleaning efficiency of mtwo, race and medin nickel-titanium (niti) rotary instruments. materials and methods: sixty mandibular molar mesial roots were selected with angle curvatures between 25-35 degrees and divided into three groups; each containing 20 teeth. canals were prepared with the rotary files and irrigated with 2.5% naocl solution after each instr...

so42-/zno-tio2 catalyst was prepared by sulfating zno-tio2 powders with h2so4 solution. the catalyst was characterized by xrd, ir and hammett indicator. the catalyst showed strong acidity(h0 ≦-16.0). the optimum conditions are found that the calcination temperature is 823k and the soaked consistency of h2so4 is 1 mol/dm3. then so42-/zno-tio2 was applied as the catalyst in the catalytic synthesi...

this study was conducted to compare the methods of seed bedpreparation in rangelands of khash region in sistan and baluchestan province iniran. a split plot design was conducted based on randomized complete blockdesign with three replications in 1999. five seed bed preparation methods wereused as main plot as: 1) seed sown by passing livestock. 2) seed sown machinery.3) seeds sown as drilled in...