AIM To determine whether metal type, cement type and the use of ultrasonic vibration influence the amount of tensile force required to remove parallel-sided, prefabricated, metal posts from tooth roots. METHODOLOGY Ninety extracted canine teeth were sectioned horizontally 1-mm coronal to the labial cemento-enamel junction and embedded in acrylic blocks. Standardized post spaces were prepared ...

OBJECTIVES The purpose of this study was to evaluate the effect of adhesive luting on the fracture resistance of zirconia compared to that of a composite resin and a lithium disilicate glass ceramic. MATERIALS AND METHODS The specimens (dimension: 2 mm × 2 mm × 25 mm) of the composite resin, lithium disilicate glass ceramic, and yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) were p...

BACKGROUND Fixed prosthodontics is a routine dental treatment and microleakage is a major cause of its failure. OBJECTIVES The aim of this study was to assess the marginal microleakage of four cements in metal ceramic restorations with adapted and open margins. MATERIALS AND METHODS Sixty sound human premolars were selected for this experimental study performed in Tehran, Iran and prepared ...

This study compared the resistance to removal by traction of abraded cylindrical metal cast posts of Cu-Al (Goldent-LA). The posts had constant length (9 mm) and three different diameters (0.9, 1.3 and 1.7 mm), and were cemented with zinc phosphate cement. The crowns of 36 sound maxillary canines were sectioned, the roots were immersed in resin blocks and the root canals were endodontically tre...

INTRODUCTION This in vitro study measured and compared pH and phosphate and calcium ions release of a new endodontic material (CEM cement), mineral trioxide aggregate (MTA), and Portland cement (PC) using UV-visible technique, atomic absorption spectrophotometry methods, and pH meter, respectively. MATERIALS AND METHODS Each material was placed in a plastic tube (n=10) and immersed in a glass...

Tricalcium-silicate and Tetracalcium-phosphate were prepared from ultra-pure chemical compounds via solid-state reaction at 1450 o C and 1500 o C respectively in an attempt to formulate a root end filling cement. Materials were investigated by X-ray diffraction and Transmission-electron microscope. The formulated cement comprises 60 wt% Tricalcium-silicate, 20 wt% Tetracalcium-phosphate and 20 ...

Tetracalcium phosphate nanomonetite cements have been prepared by reaction milling of tetracalcium phosphate with orthophosphoric acid ethanol solution, which was modified with different water content. The presence of nanomonetite phase significantly reduced the pH value of cement pastes during hardening. The fast transformation of reactants in cement powder mixtures was observed during hardeni...