ABSTRACT
Because of the dental profession's increased utilization of light-cured restorative materials, there has been a corresponding increase in research into the light sources used to initiate polymerization. The argon laser is one promising sources, as the wavelength of light emitted by the laser is optimal for the initiation of polymerization of composite resins. The use of argon laser [488 nm] has been suggested as a new alternative for polymerization of restorative materials. The aim of this study was to compare the shear bond strength values of one composite resin polymerized with two cuing methods: Conventional visible light curing unit [for 20 and 40 seconds] and argon-laser 488 nm [or 10 and 15 seconds curing times]. Sixty freshly extracted human molars were prepared to receive composite resin samples in four groups [15 samples each]. The teeth were centrally horizontally mounted in plastic molds with cold cure epoxy resin. Flat occlusal surfaces were prepared and smoothed. One-step self-etching dental adhesive [Xenol 11, one- step self - Etching Dental Adhesive, Dent-sply Detrey Gmbh, 78467 Kanstang, Germany] was applied to the dentine surface and cured. Composite resin [Spectrum universal composite, series 007782, Shade A2, Dentsply Detrey, Germany] was inserted into standardized Perspex mold and polymerized with a visible light curing unit and an argon laser. Samples were stored in deionized water at 37°C for 48 hours. The bonds were stressed using shear forces at a crosshead speed of 0.5 mm/min using Lloyd testing machine. The shear bond strength was calculated to the four groups and statistical analysis performed [One-way ANOVA and LSD test]
Results: there was significantly higher shear bond strength of composite cured with argon laser compared with the conventional curing method. There was no statistical significant difference between curing times of the same light source
ABSTRACT
Numerous therapeutic regimens have been used for the treatment of RAS, but permanent remission have not been obtained by any modality. Therapy was chiefly symptomatic and supportive. The present work suggested a new line of therapy for RAS, which proved markedly effective in shortening the healing period as well as prolongation of the relapse free period. Systemic and local nitrites as well as nifedipine can be used to fulfill that purpose
Subject(s)
Vasodilator AgentsABSTRACT
To evaluate the serum magnesium [Mg] levels in patients with ischemic heart disease [IHD], eighty five patients with IHD were selected from patients of coronary care unit in Mansoura University Hospital 52 with chronic IHD without myocardial infraction [MI] and 33 cases with acute MI 25 cases out of the 52 patients with chronic IDH were presented by arrhythmias and remaining 27 patients had no arrhythmias-On the other hand 16 cases with acute MI were presented by arrhythmias and remaining 17 patients were non arrhythmic. In the present study the mean serum Mg levels in patients with IHD- with and without AMI; patients with chronic IHD and patients with acute MI were significantly lower [p<0.001] than the level in normal controls. There was in significant decrease in mean serum Mg in subgroup with arrhythmias when compared to those without arrhythmias [p>0.05], however a insignificant decrease [p<0.001] was observed in patients with IHD [with and without MI] patients with chronic IHD develop left ventricular failure [LVF] when compared to those who escape this complication in the same group. Also there was significant hypomagnesemia in patients without acute MI who complicated by premature ventricular contraction [PVCs] when compared to normal controls from the present study we can conclude that hypomagnesemia- in addition to hypokalemia - is a predisposing factor to dangerous complication in patients with IHD and the addition of Mg to the conventional therapy can reduce the incidence of complications in these patients