Bücher von Nadira A Hatim

This study aims to: 1- Modify Iraqi natural waxes by adding some natural and chemical materials in order to produce new experimental modelling waxes that can be used in dentistry. 2- Evaluate the new waxes by measuring the physical properties according to ADA specification No. 24 and ISO 1561. 3- Evaluate the manipulation of the prepared experimental modelling waxes in constructing maxillary completely edentulous record base.The results showed that the addition of 20% Na-CMC, 20% gum Arabic, and 20% rosin to hard paraffin led to decrease the maximum melting point, flow, thermal expansion and dimensional changes but increase the minimum melting point and hardness of the hard paraffin. The starch is the same as other additives except that it leads to decrease the minimum melting point but increase the maximum melting point and the thermal expansion of hard paraffin. The rosin is the most effective one on the properties of hard paraffin than other additives. It was concluded that the experimental modelling waxes:(hard paraffin beeswax) and (beeswax+starch) have the most nearest properties to control and ADA specification than other waxes

The aims of this study are to modify heat cured acrylic resin denture base material into a flexible heat cured acrylic resin material by using additives {Flavoring agents and Plasticizer and to study some of it''s physical and mechanical properties.One hundred sixty of heat cured samples and standard flexite have been prepared for studying some physical properties and tensile strength. The samples have been tested to measure (Tensile strength, Water sorption, Solubility, Color change, Dimensional accuracy). The results of this study have shown that the tensile strength of heat cured acrylic resin with additives was significantly lower than the standard heat cured acrylic resin while standard flexite group was significantly higher than standard heat cured acrylic resin. For dimensional accuracy, water sorption and solubility test, the group has shown significantly lower dimensional change,water sorption and solubility than other groups with additives but still higher than control group and flexite (valplast) one during seven days periods.For color change test there has been a change in color between groups that even cannot be considered.

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.