Inorganic nanoparticles have been widely incorporated in conventional dental materials to help in improving their properties. The literature has shown that incorporating nanoparticles in dental materials in different specialties could have a positive effect on reinforcing the mechanical properties of those materials; however, there was no consensus on the effectiveness of using nanoparticles in enhancing the mechanical properties of dental materials, due to the variety of the properties of nanoparticles itself and their effect on the mechanical properties. This article attempted to analytically review all the studies that assessed the effect of different types of inorganic nanoparticles on the most commonly used dental materials in dental specialties such as polymethyl methacrylate, glass ionomer cement, resin composite, resin adhesive, orthodontic adhesive, and endodontic sealer. The results had shown that those inorganic nanoparticles demonstrated positive potential in improving those mechanical properties in most of the dental materials studied. That potential was attributed to the ultra-small sizes and unique physical and chemical qualities that those inorganic nanoparticles possess, together with the significant surface area to volume ratio. It was concluded from this comprehensive analysis that while a definitive recommendation cannot be provided due to the variety of nanoparticle types, shapes, and incorporated dental material, the consensus suggests using nanoparticles in low concentrations less than 1% by weight along with a silane coupling agent to minimize agglomeration issues and benefit from their properties.

This study aimed to evaluate the fracture resistance and patterns of implant-supported frameworks with and without a titanium base (Ti-base), using different prosthetic screw designs, and to determine how firing cycles followed by thermomechanical aging affect fracture resistance. Implant-supported zirconia frameworks were fabricated and allocated to three main groups: Ti-base with conventional screws, direct-connection with flat-seat screws, and direct-connection with conical screws. Each main group was further divided into two subgroups (n = 10). The control subgroup (C) did not undergo firing cycles or thermomechanical aging, whereas the experimental subgroup (E) underwent three consecutive firing cycles to simulate clinical zirconia veneering, followed by thermomechanical aging consisting of 5000 thermocycles and 1,250,000 chewing cycles. Fracture resistance differed significantly between screw designs in the control and experimental groups (p = 0.006 and p < 0.001, respectively). The combined effect of firing cycles and thermomechanical aging did not significantly affect fracture resistance in Ti-base and conical screw designs, whereas the flat-seat screw design showed a significant increase (p = 0.002). The failure pattern involved frequent deformation of prosthetic screws and multi-unit abutments (MUAs) in direct-connection designs. In contrast, the Ti-base design prevents such deformation, a benefit not present in direct-connection designs.