The aim of this study was to determine the cutting ability of chemical vapor deposition (CVD) diamond burs coupled to an ultrasonic dental unit handpiece for minimally invasive cavity preparation. One standard cavity was prepared on the mesial and distal surfaces of 40 extracted human third molars either with cylindrical or with spherical CVD burs. The cutting ability was compared regarding typ...

During the electrophysiologic study of 435 patients referred for evaluation of WolffParkinson-White syndrome, 42 (10%) had preexcited reciprocating tachycardia (defined as a macroreentrant tachycardia that used an accessory atrioventricular [AV] pathway for antegrade conduction). The ages of the patients ranged from 9 to 67 years (27 + 14). Thirty-three were male patients, nine female, and eigh...

The given paper is aimed at constructing the general circuit of heat processes in a semihermetic reciprocating refrigerant compressor as a basis of application of new ecology-friendly refrigerants as well as optimizing design parameters of compressor. While performing this work the following problems were solved: 1. Experimental research of heat processes in a semihermetic refrigerant reciproca...

The anti-suck-back ability of five new high-speed air turbine handpiece models was evaluated in this study. First, suck-back pressure with water displacement within a glass tube was measured. Next, under three different conditions, how many on-off times it takes before fluorescent stains became visible on a piece of gauze at the exhaust vent was counted and the presence of fluorescent stains on...

BACKGROUND Dental unit waterlines (DUWLs) are ideal environment for development of microbial biofilms. Microbial contamination of water in DUWLs is thought to be the result of biofilm formation as it could serves as a haven for pathogens. The aim of this study was to assess microbial quality of water in dental unit waterlines of dental units located at the dental school of Isfahan University of...

During the electrophysiologic study of 435 patients referred for evaluation of Wolff-Parkinson-White syndrome, 42 (10%) had preexcited reciprocating tachycardia (defined as a macro-reentrant tachycardia that used an accessory atrioventricular [AV] pathway for antegrade conduction). The ages of the patients ranged from 9 to 67 years (27 +/- 14). Thirty-three were male patients, nine female, and ...

Analysis of reciprocating equipment piston rod leads to nonlinear elastic-plastic deformation analysis of rod with initial imperfection under axial dynamic load. In this paper a new and effective model and analytical formulations are presented to evaluate dynamic deformation and elastic-plastic stresses of reciprocating machine piston rod. This new method has capability to account for geometric...

PURPOSE This study evaluated in vivo 2 different obturation techniques (lentulo spiral mounted in a slow-speed handpiece and hand-held) in primary teeth. METHODS The study was carried out on 24 children (mean age = 6.71 years) who had received 50 single-visit zinc oxide and eugenol (ZOE) pulpectomies in primary molars. The root canal filling materials were deposited into the canals either by ...