Abstract: The use of indirect, all-ceramic restorations has grown in popularity among dentists. Studies have demonstrated that for indirect ceramic restorations to be effective over time, cement and ceramic must be bonded in a stable manner. Chemical, mechanical, and laser irradiation are among the methods used to precondition ceramic surfaces in order to increase bond strength.The objective of the study: This study was performed to investigate the roughness values and surface topography of lithium disilicate glass-ceramic treated with conventional methods and different Er,Cr:YSGG, and fractional CO2 laser conditioning parameters.Material and methods: Sixty samples of lithium disilicate glass-ceramic were divided as follows: 1- (n = 10) untreated; 2- (n = 10) Hydrofluoric acid etched; 3- (n = 10) conditioned by Er,Cr: YSGG laser at (7 W, 25 Hz, 50/50% Water/Air, pulse duration 60 us, irradiation time 2 min); 4- (n = 10) conditioned by Er,Cr:YSGG laser at (5 W, 25 Hz, 50/50% Water/Air, pulse duration 60 us, irradiation time 2 min); 5- (n = 10) conditioned by fractional CO2 laser at (power 8 W, pulse duration 10 ms); 6- (n = 10) conditioned by fractional CO2 laser at (power 6 W, pulse duration 10 ms). Then evaluated by: Profilometer, and scanning electron microscopy.Results: The highest roughness values were found in CO2 laser power 8 W treated samples, followed by Er,Cr:YSGG laser power 7W treated samples. The hydrofluoric acid-etched samples showed roughness values comparable to those of CO2 laser-irradiated samples with a power of 6 W. The untreated sample showed the smoothest surface with the lowest roughness value.Conclusion: The application of Er,Cr:YSGG, fractional CO2 lasers enhances the surface roughness of lithium disilicate samples positively, showing the promised results of using these parameters in bonding procedures.
Abstract
Magnetic abrasive finishing (MAF) is one of the advanced finishing processes, which produces a high level of surface quality and is primarily controlled by a magnetic field. This paper study the effect of the magnetic abrasive finishing system on the material removal rate (MRR) and surface roughness (Ra) in terms of magnetic abrasive finishing system for eight of input parameters, and three levels according to Taguchi array (L27) and using the regression model to analysis the output (results). These parameters are the (Poles geometry angle, Gap between the two magnetic poles, Grain size powder, Doze of the ferromagnetic abrasive powder, DC current, Workpiece velocity, Magnetic poles velocity, and Finishi
... Show MoreThe electrical properties of pure NiO and NiO:Au Films which are
deposited on glass substrate with various dopant concentrations
(1wt.%, 2wt%, 3wt.% and 4wt.%) at room temperature 450 Co
annealing temperature will be presented. The results of the hall effect
showed that all the films were p-type. The Hall mobility decreases
while both carrier concentration and conductivity increases with the
increasing of annealing temperatures and doping percentage, Thus,
indicating the behavior of semiconductor, and also the D.C
conductivity from which the activation energy decrease with the
doping concentration increase and transport mechanism of the charge
carriers can be estimated.
The research was conducted between 2017 and 2019 at the College of Agricultural Engineering Sciences and Laboratory of Plant Tissue Culture for Postgraduate Studies at the University of Baghdad. One experiment used a totally random design. The experiment examined the effects of PEG (Polyethylene glycol) at concentrations of 0, 2, 4, 6, and 8% on the development of three sunflower types (Ishaqi-1, Aqmar, and AL-Haja) exposed to UV-C rays for 40 minutes as a result of the growing of the juvenile peduncle outside the live body. The aim of the study was to better comprehend the physiological and biochemical changes caused by water stress on the callus of several sunfl
Background: Sperm motility disorder is an important cause of infertility in male, and one of the causes of reduced motility of the sperm is the disorders of the mitochondria because it provides the required energy for sperm motility, Laser biostimulation or low-level laser therapy has a positive effect on the mitochondria and led to increasing the synthesis of ATP. Method: Twenty fresh human semen samples were used in this research study, each sample was separated into two portions, one was used as control which is not exposed to the laser beam and the other was irradiated with the wavelength of 410 nm diode laser with an output power of 100 mW and an exposure time of 60 seconds, then the measurement of
... Show MoreBackground: An oily calcium hydroxide formulation proved over the last years to be highly efficient in promoting bone regeneration in closed defects as periapical lesions, cysts, or post-extraction defects. The aim of the present study is the assessment of the outcome of treatment of deep intrabony periodontal defects with an Open Flap Debridement) (OFD) + combination of {(30% Hydroxyapatite HAp + 70% ?-Tricalcium Phosphate granules mixed with an Oily Calcium Hydroxide Suspension (OCHS )} and compare the results with {(OFD) alone)}. The combination of OCHS& TCP was used in humans with a sort of positive results, and more conduction of studies was recommended. Material and method: The sample of this study composed of sixteen patients;
... Show MoreUrinary tract infections (UTIs) mean microbial pathogens in the urethra or bladder (lower urinary tract). Important risk factors for recurrent UTI include obstruction of the urinary tract, use of a bladder catheter or a suppressed immune system. This study aims to isolate and identify bacteria from patients with TCC-bladder cancer or patients with a negative cystoscope and estimate antibiotic susceptibility patterns and evaluate some of the virulence factors. From a total of 62 patients with TCC-BC or negative cystoscope, only 35 favorable bacterial growths were obtained, including Escherichia coli (UPEC), a significant bacterial isolate, and Stenotrophomonas maltophilia. The percentage of multi drug-resistance bacteria
... Show MoreThe current study aimed to isolate and diagnose Candida spp yeasts that cause candidiasis with a PCR device from patients reviewed for some hospitals in Baghdad city and by 190 samples, the study recorded 123 isolates and the total percentage of infection was 64.7% .Samples were taken from different clinical cases of the vagina, blood and mouth and the Candida spp were (70.37%, 41.26%, 86.95%) respectively. Five types of yeasts were isolated and diagnosed, namely C. albicans, C. tropicalis, C. parapsilosis, C. krusei and C.glabarta. They were confirmed by PCR device and the most notable were yeast C. albicans, where 91 isolates were found, 73.98%, while the lowest infection was recorded. C.glabartawith 3 isolates, at 2.43%, significant diff
... Show MoreIncremental sheet metal forming is a modern technique of sheet metal forming in which a uniform sheet is locally deformed during the progressive action of a forming tool. The tool movement is governed by a CNC milling machine. The tool locally deforms by this way the sheet with pure deformation stretching. In SPIF process, the research is concentrate on the development of predict models for estimate the product quality. Using simulated annealing algorithm (SAA), Surface quality in SPIF has been modeled. In the development of this predictive model, spindle speed, feed rate and step depth have been considered as model parameters. Maximum peak height (Rz) and Arithmetic mean surface roughness (Ra) are used as response parameter to assess th
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