Abstract: Objectives: To investigate the effect of temperature elevation on the bonding strength of resin cement to the zirconia ceramic using fractional CO2 laser. Background: Fractional CO2 laser is an effective surface treatment of zirconia ceramic, as it increases the bonding strength of zirconia to resin cement. Methods: Thirty sintered zirconia discs (10 mm diameter, 2 mm thickness) were prepared and divided to three groups (N=10) and five diffident pulse durations were used in each group (0.1, 0.5, 1, 5 and 10 ms). Group A was treated with 10 W power setting, group B with 20 W and group C with 30 W. During laser irradiation, temperature elevation measurement was recorded for each specimen. Luting cement was bonded to the treated zirconia surfaces and cured for 30 seconds. Shear bond strength was evaluated by a testing machine (universal) with bond failure mode determination. Results: The lowest temperature elevation measurement of the irradiated specimen which gave maximum shear bond strength was about 1.6±0.3 Ċ higher than ambient room temperature (27±0.2 ºC). Apparent micromechanical irregularities were seen in the treated samples and cracks formation with increased pulse duration and power setting were also observed. Conclusions: The temperature elevation is a vital factor in the surface roughness of zirconia ceramic with fractional CO2 laser irradiation and the lowest temperature elevation at best shear bond strength of zirconia ceramic to the resin cement is satisfied with the shorter pulse duration of 0.1 millisecond.
Background: Dental implants act as infrastructure for fixed restoration to look like as a natural tooth. Osseointegration is a biological events and considered as a base for success of dental implant. The aim of this study is to evaluate the bond strength between bone and Ti implant coated with mixture of nano hydroxyapatite-chitosan-collagen compared with Ti implants coated with nano hydroxyapatite implanted in rabbit tibia, after different period of implantation time (two and six weeks) by torque removal test. Material and methods: 36 screws of commercially pure titanium; 8mm in length and 3mm diameter , 18 screws coated with mixture of nano hydroxyapatite-chitosan-collagen and18 screws coated with nano hydroxyapatite by dip coating. St
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Background: The aim of this study was to determine phototoxic effect of visible blue light on anaerobic periodontal pathogens namely Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. Materials and methods: Strains of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis were isolated from pockets of systemically healthy patients aged between 35-55 years old with pocket depths of 5-6 mm, the bacteria cultured on special blood Agar plates solid media, then subjected to visible blue light emitted from commercially available light cure devise (LED curing light); that emits blue light (400-500nm) of 1000mw energy at different periods of time exposures, then the CFU of each plate was measured by direct colony count
... Show MorePseudomonas putidaPST-1 isolate isolated from soil of plant root was used for high production of indole acetic acid. Indole acetic acid (IAA) production is a major property of rhizosphere bacteria that stimulate and facilitate plant growth. Optimization of indole acetic acid production was carried out at different cultural conditions of pH temperature, incubation period, and the amount of inoculum of bacteria. The best chemical medium for high IAA production (82 Mg/ml) was Luria-Bertani broth medium consisted of 1.2gm tryptophan and 10gm peptone in their components, while the cheese whey medium was the best natural medium for IAA production was (66 Mg/ml). IAA production byPseudomonas putida PST-1 was optimized by studying some factors t
... Show MoreIn Iraq; there is a great demand for handling some epidemic diseases such as hyperglycemia and hyperlipidema through searching some medical plant extracts which the country is rich with and contains an important phytochemicals that may solve the incidence of such cases. Aloe vera that cultivated in Iraq, is known to be rich with biological active constituents. The aim of the present study; the plant gel extract was subjected to treat an induced diabetic lab mice through injecting streptozotocin dose with high fatty food to elevate lipid profile before induction of the gel oral treatment of the plant. In the study results: the oral administration of A.ver
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The Nahr Umr Formation, one of the most important Cretaceous formations and one of the main generating reservoirs in southern Iraq and neighboring regions, was chosen to study and estimate its petrophysical properties using core plugs, lithofacies, and well logs from five wells in the Noor oilfield. Reservoir properties and facies analyses are used to divide the Nahr Umr formation into two-member (limestone in the upper part and main sandstone in the lower). Limestone members are characterized by low reservoir properties related to low effective porosity and permeability while the main sandstone member is considered as a reservoir. Four lithofacies were recognized in the main sandstone member of the Nahr Umr Formation according to petrog
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The acute toxicity effects of (2,4-D) pesticide to the common carp and grass carp was determined through 24, 48, 72 and 96 hr. Group of eight Common carp (Cyprinus carpio L., 1758; Pisces, Cyprinidae) and group of eight of grass carp (Ctenopharyngodon idella) were exposed to the 2,4-d. Lethal concentration (LC50) was determined with probit analysis. The median lethal concentration (LC50) values for common and grass carp were (157.77, 157.25, 156.41 and 152.62) and (115.92, 114.92, 112.94 and 96.52) respectively. Behavioral changes of the above mentioned species were examined for various herbicide concentrations.
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This paper performance for preparation and identification of six new complexes of a number of transition metals Cr (lII), Mn (I1), Fe (l), Co (II), Ni (I1), Cu (Il) with: N - (3,4,5-Trimethoxy phenyl-N - benzoyl Thiourea (TMPBT) as a bidentet ligand. The prepared complexes have been characterized, identified on the basis of elemental analysis (C.H.N), atomic absorption, molar conductivity, molar-ratio ,pH effect study, I. Rand UV spectra studies. The complexes have the structural formula ML2X3 for Cr (III), Fe (III), and ML2X2 for Mn (II), Ni (II), and MLX2 for Co (Il) , Cu (Il).