Introduction: This study aimed to assess the effects of various nicotine concentrations in flavored electronic cigarettes (e-cigarettes) on the surface roughness, microhardness, and color stability of restorative materials and enamel structure. Methods: The study utilized nanohybrid packable...

Background: Candida albicans adhesion to denture base materials is a primary contributor to denture stomatitis. To address this issue, numerous studies have explored the incorporation of various additives into denture base resins to enhance their antifungal properties. Titanium tetrafluoride (TiF₄) is an inorganic fluoride compound that has proven antimicrobial properties but has not yet been tested with denture materials. This study aimed to evaluate the effect of TiF₄ addition into different denture base materials on antifungal activity, surface roughness, hardness, and color properties. Methodology: A total of 200 disc-shaped specimens were prepared—100 heat-polymerized acrylic resins and 100 3D-printed NextDent resins. Four different concentrations of TiF₄ were incorporated: 1 wt%, 2 wt%, 3 wt%, and 4 wt% for both resins, while one group of each resin remained unmodified as a control. All specimens were subjected to thermal cycling for 5000 cycles, and four tests were conducted: Candida albicans adherence, surface roughness, hardness, and color change. A scanning electron microscope (SEM) was used to prove Candida albicans colonies’ adhesion on the specimens’ surfaces, and Fourier-transformed infrared (FTIR) analysis was performed to show the presence of TiF₄ in the resin material; data were analyzed using one-way ANOVA followed by a post hoc test (α = 0.05). Results: TiF₄ significantly reduced the Candida albicans adhesion to heat-polymerized specimens (p < 0.001). Compared to the control group, the incorporation of TiF₄ resulted in a substantial reduction in C. albicans colony counts, with reductions of approximately 97.6% in 1HP, 97.2% in 2HP, 97.4% in 3HP, and complete inhibition (100%) in 4HP. However, there was no significant difference between the 3D-printed ones (p = 0.913). Surface roughness, hardness, and color change of heat-polymerized groups were not significantly affected by TiF₄ (p > 0.05) except the color of the group treated with 4% (p < 0.05). For the 3D-printed groups, no significant differences were detected between the groups regarding candida count, hardness was significantly increased at 2% TiF₄ compared to the control (p = 0.002), and roughness was least with 4% TiF₄, while the color varied significantly between the groups (p < 0.001). Conclusions: TiF₄ addition decreased Candida albicans adhesion to heat-polymerized denture base materials but showed no antifungal effect on the 3D-printed resin. While roughness remained low in 3D-printed groups at higher concentrations. Hardness was not significantly altered in the heat-polymerized resin, whereas it increased significantly in the modified 3D-printed resin. Color stability was compromised at higher TiF₄ concentrations, particularly in the 3D-printed groups. The type of denture base material and TiF₄ concentration both influenced antifungal activity and denture surface properties.

This chapter chronicles the long history of human efforts to manipulate organisms, commencing with the foundational practices of early agriculture and selective breeding. It then charts the intellectual and experimental progress that led to the emergence of molecular biology, providing the essential framework for understanding and intervening in biological systems at the molecular level. The subsequent sections detail key milestones in the fields of genomics and the transformative development of genome editing technologies. The chapter culminates in an in-depth exploration of the core genome editing tools that are revolutionizing biological research and biotechnology. This includes a detailed examination of clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 and its widespread impact, followed by discussions of transcription activator-like effector nucleases (TALENs) and zinc finger nucleases (ZFNs), highlighting their mechanisms and contributions to achieving precise and targeted genetic modifications. In addition, the pros and cons of each technology in the genetic engineering of organisms were summarized. This historical and technological overview illustrates the remarkable advancements in our ability to intentionally alter the genetic makeup of organisms, with profound implications across diverse scientific domains.

Objective: This study aimed to assess the impact of different adhesive systems on the color stability of composite veneers following their exposure to various common beverages. Materials and Methods: A single layer of commercially available adhesives (4th and 7th generations) and two experimental adhesives based on hydroxyapatite and bioactive glass were applied, followed by composite restoration on incisor typodonts. The typodonts were prepared with depths of 0.3, 0.5, and 0.7 mm at the cervical, middle, and incisal regions, respectively. Samples from each group were immersed in coffee, Cola, and deionized water, and color stability was analyzed on days 1 and 60. One-way and two-way analyses of variance were performed. Results: The interaction between groups and solutions was statistically significant (p = 0.001) across all tooth regions. Coffee and Cola caused significant color changes (p = 0.001). The 4th generation demonstrated better color stability than the 7th generation in the middle and cervical regions (p-values = 0.083 and 0.003, respectively). The findings showed that the bioactive glass-based bonding agent exhibited greater discoloration than the hydroxyapatite-based adhesive (p = 0.001). Conclusions: The composite thicknesses are influenced differently by adhesives with respect to shade matching. Bioactive materials-based adhesives showed more resistance towards color change than commercial adhesives.