Background: This study aimed to evaluate the effect of zirconia different surface treatments (primer, sandblast with 50μmAl2O3, Er,Cr:YSGG laser) on shear bond strength between zirconia surface and resin cement. Material and methods: Sixty presintered Y-TZP zirconia cylinder specimens (IPS e.max ZirCAD, Ivoclar vivadent) will be fabricated and sintered in high temperature furnace of (1500 C for 8 hours) according to manufacturer’s instructions to the selected size and shape of (5mm. in diameter and 6mm in height). All specimens were ground flat using 600.800.1000.1200, aluminum oxide abrasive paper to obtain a standardized surface roughness. Surface roughness values were then recorded in µm using surface roughness tester (profilometer) to obtain a standardized data base line for all samples. The specimens were then randomly divided into three main groups (n=20); group A: no surface treatment (control group), group B: specimens in this group treated with 50μm Al2O3 and group C: specimens in this group treated with Er,Cr:YSGG laser. Sixty sound human premolars were used in this study, after construction of acrylic blocks, the occlusal surface of the teeth were ground flat, with diamond cutting disk to obtain a flat dentine surface . Prior to cementation of zirconia cylinders to tooth specimens subgroups (A1,B1,C1) will receive a coat of metal/zirconia primer and left to react for three minutes, while the subgroups (A2,B2,C2) were left undisturbed. Bonding surface of zirconia cylinder was then luted with SpeedCEM self adhesive resin cement under a static load of 2Kg. placed on the vertical arm of the surveyor and allowed to auto cure for 4minutes.The final cemented specimens were then stored in distilled water at room temperature for 24hours. All specimens were subjected to shear loading force in a universal testing machine at crosshead speed of 1mm/min. The shear bond strength values were analyzed statistically with one-way ANOVA; the fractured surfaces of zirconia cylinders were examined with a stereo-microscope to observe the failure mode. Results: The air borne-particle of 50μm followed by primer application showed significantly the higher bond strength than other groups. Conclusion : Within the limitation of this study, the results showed that sandblasting the bonding surface of zirconium cylinders with 50μmAl2O3 produced the highest values of shear bond strength , also the use of primer enhanced shear bond strength as well. Keyword: zirconia surface treatments, shear bond strength.
The toxicity effect of Chanca piedra (Phyllanthus niruri)leaves extract was studied on albino rats. Rats were divided into four groups, four per group. Group 1 received water and feeds only, whileonly. Groups 2, 3, and 4 were administered doses of the extract 200 mg/kg, 400 mg/kg, and 800 mg/kg body weight respectively. Parameters studied were indices of liver and kidney function. Results showed that final body weight, serum, AST, ALP, urea, Creatinine, and some electrolytes were not affected by the administration of the different doses of the extract. ALT significantly increased by administration of 200 mg/kg and 400 mg/kg of the extract when compared with the control. Besides, there was asignificant increase in the level of
... Show MoreGel-biopolymers were prepared by different weights of two polymers (PVA, and PEG) dissolved with distilled water. Thick films of these polymers were prepared by using the casting method, with different thicknesses (t= 0.48, 0.34mm for PVA and t=0.58 mm for PEG). The objective of this research is to determine the viability of the organic polymer films of PEG and PVA on decomposition and the time required for their degradation in the soil. The purpose is to use these polymers in industry without leaving plastic residues along with the possibility of their application as fertilizers for soil. The results showed that PEG film was degraded during the first week, while PVA film was changed in weight from 0.3 to 0.23 g and thickness from
... Show MoreThe aim of the research is to determine the impact of evaluation of investment projects after the preparation of investment budgets taking into consideration within the investment budgets the concept of competitive strategy, as the harmony between the preparation of investment budgets and competitive strategy will contribute to the success of economic unity and achieve profits well and achieve a competitive advantage. Strategies for economic units because the most important factor to them is the costs produced and the progress of the research problem is focused on "Is it possible to include a strategy of competition, especially within the investment budget when prepared The study concluded that the investment plan prepared by the
... Show MoreThermal properties of soils are important in buried structures contact problems. Although laboratory is distinctly advantageous in measuring the thermal conductivity of soil under ideal condition, given the ability to simulate relatively large-scale in place of soil bed, the field thermal conductivity of soil is not yet commonly used in many types of research. The use of only a laboratory experiment to estimate thermal conductivity may be the key reason for overestimation or underestimation it. In this paper, an intensive site investigation including field thermal conductivity tests for six different subsoil strata were performed using a thermal probe method (TLS-100) to systematically understanding the effects of field dry density, water c
... Show MoreIn this paper we study the selection of cognitive elements and criteria of the inflectional structure of the Russian and Arabic languages in the process of speech communication. Phonetic-physiological principle is the main parameter by which the elements and criteria of cognitive activity in the presented study are distinguished. On the basis of the above mentioned parameter, we select the investigated criteria and elements. The first criterion is semantic, reflects the accordance of the elements of thinking to sound combinations in the studied languages, and allows us to distinguish the second criterion – morphonological. The second criterion depends on the phonetic changes of these combinations occurring in the process of speech activit
... Show MoreThis study deals with the application of surface-consistent deconvolution to the two-dimensional seismic data applied to the Block 11 area within the administrative boundaries of Najaf and Muthanna Governorates with an area of 4822 , the processed seismic data of line (7Gn 21) is 54 km long. The study was conducted within the Processing Department of the Oil Exploration Company. The gap surface- consistent deconvolution was applied using best results of the parameters applied were: The length of the operator 240, the gap operator 24, the white noise 0.01%, the seismic sections of this type showed improvement with the decay of the existing complications and thus give a good continuity of the reflectors
... Show MoreSoil resistivity depends on many overlapping factors, which influence it in various ways. The aim of this study was to determine the effects of some physical and chemical factors on soil apparent resistivity. The results of field, laboratory, and statistical studies revealed a complex relationship between water content, pH, and salinity with soil apparent resistivity. The results showed that water content had a clear effect on apparent resistivity, as it increased significantly when water content value decreased to less than about 5%. The results also showed that increasing the salinity ratio at the expense of water content led to an increase in the apparent resistivity values. The apparent resistivity values also increased significantly
... Show MoreBackground: The displacement of artificial teeth during complete denture construction presents major processing errors in the occlusal vertical dimension which were verified at the previous trial denture stage. The aim of this study was to assess the effect of delay in processing after final flask closure and tension application on the vertical acrylic and porcelain teeth displacement of complete dentures constructed from heat cured acrylic and the results were compared with the conventional processing method. Materials and methods: forty samples of identical maxillary complete dentures were constructed from heat polymerized acrylic resin. These samples were subdivided into the following experimental subgroups in which each subgroup contai
... Show MoreBackground This study aimed to evaluate the efficacy of once-daily liraglutide as an add-on to oral antidiabetics (OADs) on glycemic control and body weight in obese patients with inadequately controlled type 2 diabetes (T2D). Methods A total of 27 obese T2D patients who received 7 months (0.6 mg/day for the first month, 1.2 mg/day for 3 months, and 1.8 mg/day for 3 months) of liraglutide treatment as an add-on to OADs were included. Data on body weight (kg), fasting plasma glucose (FPG, mg/dL), postprandial glucose (PPG, mg/dL), and HbA1c (%), were recorded. Results Liraglutide doses of 1.2 mg/day and 1.8 mg/day were associated with significant decreases in body weight (by 8.0% and 11.9%, respectively, p < 0.01 for each) and HbA1c (by 20.0
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