Aims: The aims were to evaluate mandibular residual ridge resorption for patients wearing lower complete dentures made of heat curing acrylic resin lined with acrylic soft liner and compare it with patients wearing conventional heat curing dentures and compare patients satisfaction with dentures for both groups. Materials and Methods: Residual ridge resorption was evaluated in 35 male patients through a period of 6 months by means of digital panoramic radiographs, the patients divided into three groups, first group 5 patients not used prostheses, the second group 15 patients worn conventional heat curing dentures and the third group 15 patients worn dentures lined with acrylic based soft liner, the patients also surveyed about their satisfaction with dentures. Results: The results indicated insignificant difference in the rate of residual ridge resorption between the three tested groups in 6 months period. Conclusions: There is no significant difference between conventional heat curing dentures and dentures lined with acrylic based soft lining material regarding the rate of residual ridge resorption. Regarding denture satisfaction, most patients seem to have more comfortable denture and better chewing ability by using soft liners.

Aims:To study the effect of metal oxide nanoparticles (MgO, ZrO2, ZnO) on acrylic based soft liner surface properties and FTIR. Materials and Methods: Acrylic-based softliner specimens were prepared by adding three different concentrations (0.5, 1, and 2) %wt of metal oxide nanoparticles (MgO, ZrO2, ZnO). A disk-shaped specimens with 30mm diameter and 3mm thickness were prepared for shore (A) hardness test to evaluate the surface hardness of modified soft liner. The surface roughness of soft-liner samples (10X10X2mm) was tested by a profilometer. FTIR analysis was conducted to evaluate chemical reaction that may occur between acrylic-based soft liner and nanoparticles. Results: there were no chemical reaction carried out between soft liner and metal oxide nanoparticles at different concentration-surface hardness (shore A) was increased as nanoparticles concentration increased in modified resin. Nanoparticles with 1 and 2% concentration incorporated in soft liner had lower surface roughness value. Conclusions: Metal oxide nanoparticles have improved the surface texture of acrylic-based soft liner, while the hardness of modified soft liner was increased with nanoparticles concentration increases.

Aims: To investigate the effect of different concentrations of ZnO nanoparticles on the compressive strength of type IV dental stone. Materials and methods: Total specimens of this research was 66 specimens, it was divided into 3 groups, the first one for wet strength , second group for dry strength and third groups for scanning electron microscope analysis. 0.2%, 0.5% , 1.0% ,1.5% and 2.0% weight of ZnO were incorporated into type IV dental stone. The study evaluated both wet and dry compressive strength and compared them with the control specimen and investigate it under SEM. The results of the study were analyzed statistically by (Mean ± standard deviation, ANOVA and Duncan's multiple range test) and the results were considered significant at p ≤ 0.05. Results: The compressive strength decreased in comparison to control specimens. This drop in strength value is not significant in wet strength, while significant in dry strength. SEM image exhibited the morphology of both stone crystals and zinc oxide NPs and exhibited the distribution of NPs inside the specimens Conclusions: The study showed that incorporation of zinc oxide nanoparticles into dental stone reduced the compressive strength property of dental stone and NPs evenly distributed into dental stone.

Aims:To evaluate the effect of the addition of MgO, ZrO2, ZnO nanoparticles in different concentration to acrylic based soft liner on candida Albicans adhesion. Materials and methods: acrylic-based soft-liner samples were prepared (10 X10 X 2mm dimension) by addition MgO, ZrO2, ZnO nanoparticles in 0.25, 0.5, 1, 2, 4 % by weight concentration to the monomer resin, the samples were immersed in Candida Albicans suspension for 1 hour then washed and dried, the microorganism were fixed and stained by crystal violet and examined by light microscope (at 400 x) to enumerate the stained candida Albicans in two occasions for thirty fields of view. Result: soft liner with 1,2,4 % by weight demonstrated that a decreased the surface adhesion of candida Albicans when compared with control group while specimens with lower concentration (0.25, 0.5% by weight) show no significant difference from control. Conclusion: addition of nanoparticles in 1,2,4 % concentration of weight to acrylic based soft liner impaired the adhesion properties of Candida Albicans, and reduce fungal induced denture stomatitis.

Objectives: Compare tensile and transverse strength of new copolymers for denture base. Materials and methods: The specimens were prepared from heat cured acrylic resin with three types of additives: Acryester B, Ethoxycarbonylethylene, and Propenoic acid at a percentage of 5% and 10%. The tensile and transverse strains were tested, recorded and compared. Results: The analysis of variance display statistically significant difference. The p-value was 0.001 for each of tensile and transverse strain tests. Conclusions: The tensile strength of the novel copolymers increased. The transverse strength of some of the novel copolymers increased.

This study aims to evaluate the effect of MRI on some physical, chemical, and mechanical properties of acrylic resin denture base materials. Four hundred fifty four samples were the total no. of sample, the samples were divided into two groups each group contain two hundred twenty seven, the 1 st sample group were pink and 2 nd groups clear heat cured acrylic resin, then the two groups is divided into four sub-groups, follow that the samples were exposed to magnetic resonance image at three different periods of time (5, 15, 30) minutes within control group respectively and samples tested for rock well, tensile strength surface roughness, water sorption, residual monomer, color change spectrophotometer and dimensional accuracy. The results obtained show that there was a change in the physical properties heat cured acrylic resin weather it is pink or clear after exposure to MRI and this change happened at different levels and variable degree, also it has shown that there was a slight tendency to change the order of an arrangement of atoms of atoms within each molecule with no well and clear evidence of chemically altering of the main material itself, at least at the circumstances of the experiment. The study concluded that the exposure acrylic to MRI at different periods of time lead to altering of physical properties and at different levels of significance.

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Aims: This study aims to evaluate the effect of (MRI) on physical, and mechanical properties of acrylic resin denture base materials. Materials and Methods: one hundred and ten samples were the total no. of samples, samples were divided into two groups each group contain two fifty five, the 1st sample group pink and 2nd groups clear heat cured acrylic resin, then the two groups is divided into four subgroups , follow that the samples were exposed to magnetic resonance image at three different periods of time (5, 15, 30) minutes within control group respectively and samples tested for indentation hardness, tensile strength. Results: the results obtained to show that there was a change in the physical properties "heat cured" acrylic resin weather it is "Pink" or "Clear" after exposure to (MRI) and this change happened at different levels and variable degree, also it has shown that there was a slight tendency to change order of a arrangement of atoms within each molecules with no well and clear evidence of altering of the main material itself, at least at circumstances of experiment. Conclusion: Exposure to (MRI) at different periods of time lead to altering of physical properties and at different levels of significant.