Objective: Elastic impression materials considered favourable decision in fixed and removable prosthesis due to ease of use and accuracy. High price tag is the main drawback. The purpose of this study was to evaluate surface detail reproduction and dimensional stability of newly introduced 3M Preliminary PentaTM VPS in comparison to other elastic impression.           Methods: Alginate, alginate replacement and 3M light body were tested for surface detail reproduction and dimensional stability. Ten samples were prepared for each using a stainless-steel die that was created according to ADA specification No. 18 and 19. Surface detail was assessed directly after setting while dimensional stability was evaluated immediately and 24hr after. The data were analysed using a paired sample t-test. Results: All the samples were able to record 75μm line for surface detail. Surface record of 3M imprintTM 4 Preliminary PentaTM VPS showed a similar result to light body. While alginate failed to reproduce 50μm and 20μm lines. Regards to dimensional stability, light body resisted change with respect to time. In contrast, alginate revealed a significant effect (p˂0.05) on dimensional stability for the same storage period while not a major effect was observed for alginate replacement.  Conclusions: Within the limitations of this study, it can be concluded that light body underwent less dimensional change than alginate and alginate replacement. It also revealed a better replication of details. Alginate replacement was more stable during the storage period with better surface detail record than alginate.

The clinical life of a maxillofacial prosthesis averages about six months before it needs to be re-fabricated. Most of maxillofacial prosthesis attached to the acrylic resin via adhesive primers detached and have to be re-attached every few months. This in vitro study established to evaluate the effect of adding calcium carbonate nanoparticles at different concentrations on the bonding strength of maxillofacial silicone elastomer to the acrylic resin, before and after accelerated aging. Seventy samples were prepared, ten samples per each group. Each silicone sample sandwiched between two strips of acrylic resin via A-330-G adhesive primer. From each group five samples were undergoing accelerated aging. All samples were tested for shear bond strength by using Instron testing machine. Calcium carbonate nanoparticles have a significant effect on the shear bond strength of maxillofacial silicone to the acrylic resin and the groups that contain the lowest concentrations of calcium carbonate nanoparticles showed the most significant changes. It CaCO3 nanoparticles in trace amount can improve the shear bond strength of maxillofacial silicone elastomer to the acrylic resin after subjecting to accelerated aging.

Most dental works require a diagnostic impression; alginate is contemplated as the most popular material used for this purpose. Titanium dioxide nanoparticles show evidence of antimicrobial activity in the recent era, for this purpose, this study aimed to evaluate the effect of adding Titanium dioxide nanoparticles on antimicrobial activity and surface detail reproduction of alginate impression material. Materials and methods: Titanium dioxide nanoparticles (purity = 99%, size= 20nm) was added to alginate at three different concentrations (2%, 3% and 5%). 84 samples were prepared in total. Samples were tested for antimicrobial activity using a disc diffusion test, and surface detail reproduction was done using (ISO 21563:2021). One-way ANOVA and independent sample t-test were used for data analysis through SPSS software. Results: for the antimicrobial test, inhibition zones for Streptococcus mutans and Candida albicans showed significant changes concerning the alteration in Titanium dioxide nanoparticle concentrations. The inhibition zone significantly increased with an increase in the percentage of Titanium dioxide nanoparticles. The mean of the inhibition zone for S. mutans was superior to C. albicans and the difference was statistically significant. Regarding surface detail reproduction, the control group, 2% and 3% groups manifested very similar results, only the group to which 5% of Titanium dioxide nanoparticles were added showed a decline in detail reproduction when compared to the other three groups. Conclusion: Within the limitation of this study, we can conclude that the antimicrobial activity against S mutans and C. albicans were significantly increased in modified groups, and this escalation was directly linked to the increase in Titanium dioxide nanoparticles concentration. In contrast, the surface detail reproduction was decreased when adding 5% Titanium dioxide nanoparticles to alginate.

Samaraie (2) ; Fahd S. Ikram (3) Background and objectives: Radiolucency of poly methyl methacrylate denture base resin is of great concern, and many approaches have been used to make acrylic resin dentures more radiopaque.The purpose of this study was to prepare a modified heat cure ploy methyl methacrylate denture base resin by incorporation of different weight percentages (2%, 3%, 4%, 5%, and 6%) of CaCO3 nanofiller particles, to increase its radiopacity. Materials and methods: CaCO3 nanofiller particles (coated with a special coupling agent) were dispersed and sonicated in the acrylic monomer (liquid) in different percentages, then mixed with acrylic powder. For each test 60 specimens were prepared, the specimens were divided into 6 groups (10 for each) coded I to VI. Group I was the control group (unmodified specimens), the remaining five groups were reinforced with CaCO3 nanoparticles to achieve loading of 2%, 3%, 4%, 5%, and 6% by weight. Some physical properties were evaluated. Results: There was a slight change of color of the acrylic, in groups II, III and IV, but there was an obvious color change of group V and VI. Also, there was a highly significant increase in the radiopacity in groups IV, V and VI. Conclusion: Addition of 4% CaCO3 nanoparticles to the heat cure acrylic resin increases the radiopacity of the denture base significantly, without adverse effects on the color.

Objective: Heat cure acrylic is the most common used material for fabrication of dental prosthesis. This in vitro study was undertaken to discover the effect of nanoparticles on antibacterial properties of the dental base. Methods: Nanosized Silver and Copper oxide were impregnated at 1%, 3% and 5% by weight to the monomer of methyl methacrylate with the aid of probe sonicator before mixing it with acrylic powder. Seventy samples were prepared to determine the effect of the nanoparticles on Streptococcus mutans and Escherichia coli.     Results: The results for Streptococcus mutans revealed a statistically significant difference (p<0.05) for both nanoparticles at the three concentrations except for 1% silver. The most influential concentration on the tested material was 3% copper oxide which caused a 49% decline. Regarding Escherichia coli, only 3% and 5% of silver showed a statistically significant difference. Conclusions: Within the limitations of this in vitro study, it can be concluded that the addition of Silver nanoparticles into heat-cure acrylic was more effective against Streptococcus mutans than Escherichia coli. Regarding Copper oxide nanoparticles, it caused a drastic reduction in Streptococcus mutans activity but with no significant effect on Escherichia coli for all of its concentrations. Since denture stomatitis is caused by both bacterial species, Silver nanoparticles might be considered as a suitable additive for reducing denture induced infections.