introduction: although composite resins have improved greatly since their introduction, microleakage is one of the most frequently encountered problems. this study compared the effects of different monomer systems and layering techniques on the bacterial leakage of cl i composite resin restorations. methods: eighty-two sound human third molars were used. the teeth were randomly divided into six...

Objectives: The aim of this study was to compare polymerization depth of two bulk-fill and one conventional composite cured for different times. Methods: This in vitro experimental study was conducted on 54 composite samples (2×4×10mm) fabricated of Tetric N-Ceram bulk-fill, x-tra fil bulk-fill, and Grandio conventional composite cured for 20, 30, and 40 seconds. The microhardnes...

background the ala of the nose, with its particular texture and characteristics, poses both aesthetically and functionally intriguing challenges and is rather problematic regarding choices for reconstructive methods. both flaps and grafts have been used to restore natural structure of nasal ala. the present study summarizes a ten-year experience of reconstructive surgery using small composite g...

copper matrix composite reinforced by 1wt.% tib2 particles was prepared using in situ reaction of cu-1.4wt.% ti and cu-0.7wt.% b by rapid solidification and subsequent heat treatment for 1-20 hrs at 900ºc. high-resolution transmission electron microscopy (hrtem) characterization showed that primary tib2 particles were formed in liquid copper. heat treatment of as-solidified samples led to the f...

Background. The aim of this study was to investigate the effect of preheating methacrylate- and silorane-based composite resins on their color stability up to 40 times at 55‒60°C. Methods. Seventy-six methacrylate and silorane-based composite resin samples, with a diameter of 10 mm and a height of 2 mm, were divided into 4 groups (n=19). After the samples were prepared, their color parameters w...

objective(s) in this study, a kind of ph sensitive composite membrane was prepared and drug permeation through it was investigated in terms of ph. rationale of this study originated from the fact that a ph change which may be a result of a disease state in the body can trigger drug release. materials and methods  here, a kind of ph sensitive composite membrane containing different nanoparticle ...

In this paper, we introduce a new algebraic structure, called a UP-algebra (UP means the University of Phayao) and a concept of UP-ideals, UP-subalgebras, congruences and UP-homomorphisms in UP-algebras, and investigated some related properties of them. We also describe connections between UP-ideals, UP-subalgebras, congruences and UP-homomorphisms, and show that the notion of UP-algebras is a ...