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The aims of this study is to evaluate the effect of the of the microwave radiations on the acrylic powder itself by irradiating it with microwave radiation at different power (270watt , 360 watt) ,time (1/4 hr, ? hr), and environmental situations (dry, wet and immersed with water) to see the possibilities of improving its properties by comparing the cured samples prepared from the microwave irradiated acrylic powder with those samples prepared from control and high impact acrylic. The results showed that there is a significant increase in the transverse strength, and decrease in the hardness and residual monomer tests, especially for those groups that prepared at power 360 Watt for ? hr. The water sorption and solubility, dimensional accuracy, showed that there is no significant difference between the tested groups. FTIR test DSC and density test showed that there is a change in the microwave irradiated acrylic in contrast with the control one. Conclusions The results approved that the use of microwave radiation produce an effect on the acrylic powder, and this effect improve the transverse strength and residual monomer concentration of the denture base acrylic specially for 360

The aim of the present study was extract pure ketamine powder from ketamine hydrochloride solution; ketamine gel in different concentrations was prepared to detect the therapeutic effectiveness of it as analgesic in the form of a topical application in both human and laboratory animals.The results demonstrated that the purified ketamine was pure according to IR, UV, CHN analysis and melting point. Ketamine gel also is safe to be used topically and not irritant according to the skin irritation test, because the mean value of skin irritation index (SII) for erythema and edema was found to be zero after applied of ketamine gel in different concentrations.A significant analgesic effect of ketamine gel in humans was induced by the test formulation containing 0.5% ketamine gel and the percentages of non, mild, moderate and severe pain were (46.4, 32.1, 17.9 and 3.6)%,respectively. It was concluded from this study that a pure ketamine powder can be prepared and could be of value when used as gel through topical application in relieving pain.

The aims of this study were to detect the amount of fluoride released from the tested materials into three different storage solutions and to determine the change in the surface microhardness after storage.The amount of fluoride released from the three materials was significantly higher in acidic solutions than in neutral solutions. The Compomer released the highest amount of fluoride into the three storage solutions, while the least fluoride release was from the resin-modified glass-ionomer. The surface microhardness of the three tested materials reduced significantly after storage in neutral and acidic solutions compared to dry stored specimens. In acidic solutions, the surface microhardness was significantly lower than in neutral solutions. The Compomer showed the highest microhardness number values.

By clinical oral examination, some of the physical and biochemical analysis of human unstimulated whole saliva have been studied with their effects on the retention of acrylic denture base. The following parameters were studied: flow rate, pH, total protein, density, surface tension, viscosity and film thickness. Total protein concentration was found to be responsible for physical and chemical changes specially viscosity. There was a direct positive correlation between total protein and surface tension, viscosity, density and film thickness, while there was a negative correlation between total protein and with flow rate and pH. The results indicated that in both the first and the third groups, the physical and mathematic analysis for retention showed non significant changes while in the second group showed significant changes. The results in all groups showed that there was a positive correlation between force and wetted area and this force was due to wettability and not to water sorption.

The aims of this study are modification of locally available denture adhesives material by addition of additives (thymol, sodium fluoride and chlorhexidene) in a concentration of 2% with evaluation of some physical, chemical and biological properties of these materials using Fittydent, Bonyplus and Calcident as comparison groups. These measurements include: pH, density,viscosity, toxicity, antimicrobial effects ,infrared and ultraviolet spectra of all denture adhesive materials. The retentive ability of these materials are also measured and correlated with their viscosity. The results of this study revealed that all the materials tested have nearly a neutral pH. Bonyplus, CMC with thymol, CMC with chlorhexidine and (CMC with thymol, sodium fluoride and chlorhexidene) showed a significant antimicrobial effect. The spectrophotometric result indicated that the modified materials have similar structures to the commercial adhesives.

The aims of this study were to evaluate the effect of change in time ,temperature (increase or decrease) and some additives(Nigella sativa and Thyme oil) on the degree of conversion, residual monomer release, transverse strength, indentation hardness, volumetric and color changes of the vertex heat cured acrylic resin.The results of the present study were analyzed statistically by (Descriptive statistics, ANOVA and Duncan''s multiple range test). The results of this study showed that both changes in time and temperature showed significant changes in the degree of conversion, residual monomer, transverse strength, volumetric and color changes in the three curing cycles without additive. The used additives (Nigella sativa and Thyme oil) increased the conversion, increased the residual monomer release, showed a slight increase in volumetric change for the short cycle,(0.35-1.05) for the rapid simplified and for the regular curing cycles in comparison with their standard curing cycles without additives and color change, ?E =3.376 (which is an acceptable change in vitro) for the Thyme oil additive to the regular heat curing cycle in comparison to the standard short cycle.

The objective of this study is to prepare a chemical compounds for cleaning denture from locally available materials. The chemical compounds solutions were (sodium bicarbonate + alum), (sodium bicarbonate + citric acid), (sodium bicarbonate + apple vinegar), (sodium bicarbonate + clear commercial vinegar), (sodium bicarbonate + thyme oil), (saturated salt solution), (clear commercial vinegar), (alum). In addition, in the main study, the effects of the chemical compounds solutions were evaluated on the (color, water Sorption and transverse strength) of heat – cured denture base material. The t-test showed that the highest increase in optical density for the specimens immersed in (alum), (sodium bicarbonate +alum), (sodium bicarbonate + apple vinegar) solutions at 1/2 hr immersion and it increased more at 8 hrs immersion. The conclusions of this study showed that the safest prepared solutions on the denture base material that could be used as denture cleansers are (sodium bicarbonate{7g}+ clear commercial vinegar{5ml}), (sodium bicarbonate {2g} + thyme oil {3.57g}), (saturated salt solution {40g}) at 1/2 hr and 8 hrs of immersion.

This study aims at evaluating bracket''s slot dimensions “width, depth and labiolingual inclination”, bracket''s base curvature, bracket''s interwing gap distance, bracket''s colour, weight, microscopical evaluation of pad area and tensile bond strength after recycling the stainless steel and pure titanium brackets with different bracket recycling procedures, also evaluating bracket dimensional changes after debonding with bracket debonding pliers. No significant bracket measurement changes were occurred when utilizing bracket debonding pliers in debonding the stainless steel and pure titanium brackets. Finally, the conclusions of this study were that the microetcher method is the most effective in removing the adhesive remnant and has no significant change to the bracket measurements and the bracket removing pliers was strongly recommended in debonding the metal bracket and specially when debonded bracket is indicated for recycling.

The aim of this study was to determine the effect of some chemical materials on the physical and chemical properties of dental stone. Accordingly, three types of chemical materials (rosin, nigella stavia oil and sodium lauryl sulfate) were incorporated into three kinds of type III dental stone (Zeta, Elite and Dental stone) at four concentrations. The physical properties evaluated were water-powder ratio, setting time, setting expansion, compressive strength and hardness. The evaluation of chemical properties was done by the use of infrared and ultraviolet spectrophotoscopy.The results revealed that the incorporation of these chemical materials into each type of dental stone resulted in changing their evaluated physical properties; this change varies with the type, concentration of the added chemical material and type of dental stone being used. The change in the physical properties has been shown to be correlated with the changes in the chemical structure of dental stone as it became clear by comparing the ir-specra and uv-spectra of dental stone before and after the addition of the chemical materials.

The aims of this study are to investigate the effect of light intensity, curing time and combined effect of light intensity and curing time on the degree of conversion, depth of cure and amount of residual monomer released from composite samples cured with different light curing units. Single light cured composite restorative material (Herculite XR) exposed to different types of light curing units (Optilight LD, ULTRA-LITE 200 E plus, Astralis-VIVADENT) at a different exposure times (20, 40 and 60 seconds). The degree of conversion of composite resin samples was investigated by Fourier-transform infrared spectroscopy.The depth of cure of composite resin samples was investigated by scraping technique using a digital caliper. While the amount of residual monomer released from cured composite samples was investigated through measuring the released residual monomer in doubled distilled water with (CECIL 2000) ultraviolet visible spectrometer. The results it was shown that the low intensity LED LCU (Optilight LD) exhibit a non significant result in degree of conversion from those of high intensity (LED and QTH) LCUs at extended period of curing time.