OBJECTIVES To investigate the static frictional resistance at the bracket/archwire interface in two recently introduced bracket systems and compare them to conventional ceramic and conventional metal bracket systems. Three variables were considered including the bracket system, archwire type and archwire angulation. MATERIAL AND METHODS Four bracket systems were tested in vitro: Self ligating...

The aim of this research is to investigate different X-ray based quantitative phase analysis methods for determination of cristobalite phase content in ceramic cores. For this purpose, four popular routes including peak absolute intensity method, relative intensity ratio method, direct or calibration method and internal standard (or Alexander-Klug) method have been chosen. Some control samples ...

Objective: The main aim of this study was to compare fracture load and fracture mode of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) and metal-ceramic (MC) molar crowns using a modified test set-up to produce fractures similar to those seen in vivo, i.e. fractures of the veneering material rather than complete fractures. Materials and methods: 13 high-noble-alloy MC and 13 Y-TZP mo...

in the face of strategic and geopolitical importance of nishapur, this city was not much taken into consideration by the archeologists of the historic period. the analysis of the new findings of the ancient castle of sasanian nishapur as well as the identification of some sasanian settlements in the plain of nishapur can make it possible to re-configure the eco-political structures of the commu...

High-strength all-ceramic systems for fixed partial dentures (FPDs) is gaining popularity as an alternative to the well established metal-ceramic FPDs. Several new framework materials and technique such as lithium disilicate, aluminum oxide and yttrium tetragonal zirconia polycrystal have been developed with improved strength, marginal discrepancy and esthetics. Since not every all-ceramic syst...

The ceramic-on-ceramic bearing surface has high wear resistance and good biocompatibility in total hip arthroplasty (THA). However, the postoperative noise problem has been an important issue. The purpose of this retrospective study was to determine the incidence and risk factors of bearing surface-related noises in patients with third-generation ceramic-on-ceramic THAs. One hundred twenty-five...