RESUMEN
Background One of the frequent aesthetic issues patients confront is the loss of colour and lifeless appearance of the dentures of the base materials of their dentures after regular use. This leads to a lack of motivation to use the denture regularly. Due to the drawbacks of conventional PMMA, polyether ether ketone (PEEK) and newer polymethyl methacrylate (PMMA)-based materials have now started being used in cast partial denture frameworks due to their superior physical and biological properties. The lack of long-lasting colour is one of the main reasons for the repeat of dental prostheses. Hence, the need for the study is to help clinicians decide which would be the most suitable denture base material to be used based on colour stability. Aim To assess and compare the colour stability of PEEK, polyan, and biodentaplast denture base materials (DBMs) upon staining with distilled water, tea, coffee, and turmeric solutions after one day, seven days, and 30 days. Methods A total of 20 cuboidal specimens were constructed and immersed in distilled water, tea, coffee, and turmeric (five specimens of each material in each solution, a total of 60 specimens): Group 1: PEEK, Group 2: polyan, Group 3: biodentaplast. All specimens were subjected to colour measurements before exposure to beverage solutions, after 24 hours, on the seventh day and 30th day with a colour reflectance spectrophotometer with computer software. A one-way ANOVA test followed by post hoc Tukey's honestly significant difference (HSD) was performed for comparison of colour stability between the DBMs, revealing a significant difference between PEEK and polyan and PEEK and biodentaplast. Polyan showed the highest delta E values, followed by biodentaplast and PEEK. A two-way ANOVA test, followed by Tukey's HSD post hoc, was done to compare the staining ability of various staining solutions. Turmeric had the highest delta E values, followed by coffee, tea, and distilled water. Data were assessed using Statistical Product and Service Solutions (SPSS, version 23) (IBM SPSS Statistics for Windows, Armonk, NY) software. Results The highest mean delta E value at T1 was seen in biodentaplast immersed in turmeric (12.3900+/-0.442), and the least value at T1 was obtained for PEEK immersed in distilled water (0.4460+/-0.036). The highest mean delta E value at T2 was seen in polyan immersed in turmeric (13.0160+/-0.28962), and the least value at T2 was obtained for PEEK immersed in distilled water (0.5860+/-0.051). At T3, the highest mean delta E value was seen in polyan immersed in turmeric (16.8600+/-0.49845), and the least value at T3 was obtained for PEEK immersed in distilled water (0.700+/-0.037). Conclusion PEEK had the highest colour stability when compared with polyan and biodentaplast.
RESUMEN
In the quest to create effective sensors that operate at room temperature, consume less power and maintain their stability over time for detecting toxic gases in the environment, molybdenum disulfide (MoS2) and MoS2-based hybrids have emerged as potent materials. In this context, the current work describes the fabrication of Au-MoS2hybrid gas sensor fabricated on gold interdigitated electrodes (GIEs) for sensing harmful CO and NH3gases at room temperature. The GIEs-based Au-MoS2hybrid sensors are fabricated by decorating MoS2nanoflowers (MNF) with varying size of Au nanoparticles using an inert gas evaporation technique. It is observed that by varying the size of Au nanoparticles, the crystallinity gets modified, as confirmed by x-ray diffraction and Micro-Raman spectroscopy (µRS). The gas sensing measurements revealed that the best sensing response is found from the Au-MoS2hybrid (with an average particle size of 10 nm). This particular hybrid shows a 79% response to CO exposure and a 69% response to NH3exposure. The measurements are about 3.5 and 5 times higher than the bare MoS2when exposed to CO and NH3at room temperature, respectively. This enhancement in sensing response is attributed to the modified interfacial interaction between the Au nanoparticles and MNF gets improved, which leads to the formation of a Schottky barrier, as confirmed using x-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy analysis. This enables the development of efficient gas sensors that respond quickly to changes in the gas around them.
