This study aims to evaluate the biomechanical behavior of titanium and carbon fiber-reinforced polyetheretherketone (CF-PEEK) dental implants under varying bone densities and loading conditions using finite element analysis (FEA). A single-tooth mandibular molar implant system was modeled, comprising titanium or CF-PEEK abutment and fixture, and surrounding bone structures with four configurations: (I) fully cortical bone, (II) 2 mm cortical layer with trabecular bone, (III) 1 mm cortical with high-density trabecular bone, and (IV) 1 mm cortical with low-density trabecular bone. Vertical and oblique static loads of 100 N were applied to simulate masticatory forces. FEA results revealed that titanium implants exhibited higher von Mises stress values in the implant and abutment under oblique loading, exceeding 400 MPa, while CF-PEEK components showed reduced stress but significantly higher strain levels. Cortical and trabecular bone surrounding CF-PEEK implants received more uniform stress distribution, potentially minimizing stress shielding effects. However, fatigue life analyses indicated that CF-PEEK abutment and screw components were more susceptible to mechanical failure under oblique loads, particularly in low-density bone models. In conclusion, CF-PEEK implants offer a more physiological load transfer to bone and reduced stress shielding compared to titanium. However, their structural reliability under complex loading, especially in low-quality bone conditions, requires careful consideration. These findings support the potential use of CF-PEEK in select clinical scenarios but highlight the need for further material and design optimization.

Denture hygiene is crucial for preventing oral infections, with Candida albicans being a common fungal pathogen that can colonize denture surfaces. This in vitro study evaluated the adherence of C. albicans on two denture base materials—polyamide and polymethyl methacrylate (PMMA)—and assessed the antifungal efficacy of various chemical and natural cleansers. A total of 100 polished specimens were inoculated with C. albicans and treated with chemical agents (Listerine at 2%, 20%, 50%; Corega^®, Block Drug Company, Jersey City, NJ, USA); Protefix^®, Queisser Pharma, Flensburg, Germany and natural products (15% apple vinegar, 2% tea tree oil, 2% peppermint oil) for different durations (5, 15, 30, 480 min). Chlorhexidine (2%) and untreated samples served as positive and negative controls, respectively. Corega^® and 15% vinegar eliminated C. albicans within 5 min on both materials. 50% Listerine was effective after 5 min on PMMA but required 480 min on polyamide. Protefix^® showed full efficacy in 5 min on PMMA and 30 min on polyamide. Tea tree oil required 30–480 min for activity, while peppermint oil showed minimal effect throughout. Under the tested conditions, Corega^® appeared most effective. Natural cleansers, particularly vinegar and tea tree oil, also showed considerable anticandidal potential, suggesting they may serve as alternative agents for denture hygiene applications.