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This study investigates the effect of smokeless tobacco on the tribological properties of two commercially used dental composite materials: Tetric N-Ceram and Z350 Dentin shade. It is to evaluate the effect of smokeless tobacco on the wear properties of two dental composite materials after some stipulated period. The wear test was conducted on pin-on-disk tribometer in the presence of artificial saliva under different loading conditions of 10, 15 and 20 N. The pins of the dental composite material were immersed in tobacco solution. The tribological behavior was studied after 2 days, 3.5 days, 6 days, 15 days and 1 month which represented the real conditions for the contact of 1 week, 2 weeks, 1 month, 2 months and 5 months, respectively, between the dental material and the tobacco solution. Under different loading conditions, Z350 Dentin material exhibited much less wear than the Tetric N-Ceram material in the presence of synthetic saliva for the specimen with or without tobacco immersion. The microstructure of the pin surface was inspected using scanning electron microscopy.

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Nowadays, there is a large variety of dental restorative composite materials on the market, making it difficult to select the proper one. The mechanical properties of various dental materials determine how long they endure when used in the mouth. On the other hand, the therapeutic efficiency of these restorative materials cannot be predicted solely based on their mechanical properties. These features, on the other hand, help with the examination of the impact of changes in their composition. As a consequence, these tests can help the clinician choose the right material. The various mechanical properties can be investigated using a variety of laboratory experiments. The common laboratory tests used to evaluate the mechanical characteristics, composition, and classification of dental composite materials, as well as the factors that influence mechanical qualities, are discussed in this study.

Stimuli-responsive polymers applied to traditional textiles have received widespread attention. In this work, a new type of polymer-modified polyester fabric was prepared with interpenetrating polymer network (IPN) hydrogel. The IPN hydrogel comprised of poly (N-isopropylacrylamide) (PNIPAAm), silk sericin (SS), and silver nanoparticles (Ag NPs). The presence of the IPN hydrogel on the surface of fibers can change the wettability of polyester fabric, in response to temperature. The thermal behavior of IPN hydrogel was characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TG). DSC results indicated that the IPN hydrogel exhibits temperature-responsive behavior and the lower critical solution temperature (LCST) was around 32.9℃. The decomposition temperature of modified polyester fabric (400.5℃) was better than the original polyester fabric (335℃). TG results indicated that the polymer-modified fabric possessed higher thermal stability than the original polyester fabrics. The thermo-physiological comfort of modified polyester fabric was characterized by water contact angle and vertical wicking test. Above the LCST, the wettability of the polymer-modified polyester fabric would decrease because of the volume phase transition of IPN hydrogel. Moreover, the antibacterial activity of the modified temperature-sensitive fabric against Staphylococcus aureus and Escherichia coli was also investigated, and the antibacterial activity for both microorganisms exceeded 95%. This study provided a feasible route to fabricate the temperature-responsive textile with great antibacterial performance.

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