Ola Mohammed Abdullah Al-Jubouri

The current study aimed to evaluate the effects of incorporating magnesium oxide (MgO) and zirconium oxide (ZrO2) nanoparticles individually or in combination into heat-cured acrylic resin on the polymer structure, density, surface roughness, hardness and flexural strength for denture base applications. MgO and ZrO2 nanoparticles strengthen the polymer matrix by forming coordination bonds with carbonyl oxygens, increasing crosslinking. This increased the density and flexural strength while reducing the surface roughness but lowered the hardness at elevated concentrations. These findings suggest the potential for tailored polymer applications, improved denture performance, increased patient comfort, and longer-lasting dental prostheses.

The paper aimed to evaluate using a modified flask on surface hardness and roughness, flexural, and tensile strength for heat-polymerized acrylic resin. According to the result of this study, the mechanical properties of heat-polymerized acrylic resin were improved using a modified flask with a new metal plate.

One of the most widely used materials for the fabrication of prosthetic dental parts is acrylic resin. Its reasonable mechanical and physical properties make it a popular material for a wide range of dental applications. Recently, many attempts have been made to improve the mechanical and biological properties of this material, such as by adding fibres, nanoparticles, and nanotubes. The current study aimed to evaluate the effects of adding an antimicrobial agent, Ag-Zn zeolite, on the surface roughness and hardness of the denture base resins. Ag-Zn zeolite particles were chemically prepared and added at different concentrations (0.50 wt.% and 0.75 wt.%) to the heat cure (HC) and cold cure (CC) acrylic resins. Zeolite particles were characterized and confirmed using X-ray diffraction (XRD) and Energy-Dispersive X-ray Spectroscopy (EDX) attached with a Scanning Electron Microscope (SEM). Sixty disk shape specimens (40 mm diameter and 2 mm thickness) were fabricated from the HC and CC resins with and without the zeolite. All the specimens were divided into two main groups based on the acrylic resins, then each was subdivided into three groups (n = 10) according to the concentration of the Ag-Zn zeolite. A surface roughness and a hardness tester were used to measure the surface finish and hardness of the specimens. The analysed data showed that the surface roughness values significantly decreased when 0.50 wt.% and 0.75 wt.% zeolite were incorporated in the HC resin specimens compared to the control group. However, this reduction was not significant in the case of CC resin, while the surface hardness was significantly improved after incorporating 0.50 wt.% and 0.75 wt.% zeolite for both the CC and HC resins. Incorporating Ag-Zn zeolite with acrylic resin materials could be beneficial for improving their surface finish and resistance to surface damage as defined by the higher hardness.

with some acceptable linear dimensional changes in the finished restorations. This study aimed to evaluate linear dimensional stability and surface hardness of dental stone type IV when adding silica nanoparticles to it. 40 type IV stone specimens were prepared from stainless steel molds for linear dimensional stability and plastic mold for hardness, 20 of which contained silica nanoparticles (test group) while the other 20 were without any addition (control group). Each group was divided into subgroups containing 10 specimens for each one in order to compare the dimensional stability and hardness of them. The linear dimensional changes were measured using a digital caliper, while the hardness was tested with Vickers’ hardness test. The data were analyzed with t-test (two-sample assuming unequal variances) and p-value. The mean value of linear dimensional changes for the control group was -0.396 and -0.386 for specimens of the test group. Mean hardness was 50.638 for the control group and 53.295 for the test group. The difference was significant for linear dimensional changes and highly significant for hardness. Adding of silica nanoparticles improved the hardness and reduced the linear dimensional changes of type IV stone.

The commonly used acrylic resins for fabricating denture base suffer from poor mechanical properties. This study aimed to assess the effect of incorporating Titanium Dioxide (TiO2) nanoparticles (NPs) as a reinforcement agent on the compressive strength of different acrylic denture base materials. Thirty-two cylindrical specimens (22 mm in height and 12 mm in diameter) were prepared from PMMA resins with and without TiO2 NPs. They were allocated into two main groups according to the materials used such as cold cure and heat cure denture base resins and then divided into two subgroups each containing eight specimens: control (without nanoparticles) and experimental (with 2 wt.% TiO2 NPs). TiO2 NPs were synthesised via a chemical processing route. Particle morphology and size distribution were assessed using SEM and AFM while XRD technique was employed to determine the crystalline structure of the NPs. Compression test was performed on the specimens using a universal Instron testing machine to compare the compressive strength. Size of crystalline TiO2 NPs varied between 40 and 80 nm. The mean compressive strength for the cold cure acrylic resin (control group) and its nanocomposite (experimental group) were found to be 15.37 MPa and 17.42 MPa while for the heat cure acrylic resin and its nanocomposite were 23.04 MPa and 24.30 MPa. A statistically significant difference was recorded between the compressive strengths of cold cure acrylic resin and its nanocomposite. However, the difference was non-significant in the case of heat cure acrylic resin. The compressive strengths of both cold cure and heat cure acrylic resins increased after the incorporation TiO2 NPs.