## 4 Discussion
[59] evaluated a comparison of the hardness of a denture material based on polyamide (Deflex) with another material using injection-molded PMMA as the base, as well as a conventional PMMA material produced through compression molding. The study's findings revealed that the hardness of the Deflex specimens was notably lower than that of the other materials, indicating that the material was not as hard in comparison. Another study conducted by [PERSON] et al. [60] demonstrated that PMMA exhibited higher hardness values when contrasted with flexible resin. This outcome could potentially be attributed to factors such as a higher monomer-polymer ratio in PMMA, the bonding characteristics of the material, and the presence of the methyl-methacrylate monomer. Furthermore, the material might contain cross-linking agents. In contrast, flexible resin showcased lower hardness values and contained fewer cross-linking agents, implying that the presence of cross-linking agents could impact the surface hardness. Surface roughness stands as a fundamental attribute capable of influencing the durability of removable dentures. An increase in roughness can lead to heightened microbial adhesion, culminating in denture stomatitis [61]. Furthermore, rougher surfaces tend to accumulate more stains and discoloration, undermining the aesthetic appeal of dentures [62]. The surface properties of thermoplastic polymers manifest a range of imperfections and notably elevated roughness [63], creating an environment conducive to the colonization of microorganisms on their surfaces. The mechanical manipulation of thermoplastic materials presents challenges, hindering the attainment of a smooth and lustrous exterior [64]. The absence of this smoothness presents ideal conditions for the attachment of microbial cells. Water absorption of a substance indicates its ability to attract and take in water during use. The acrylic resin's uptake of water can function as a plasticizer, resulting in softening, color changes, and a decline in its mechanical attributes like hardness, transverse strength, and fatigue threshold [65]. Nonetheless, the absorption of water leads to a three-dimensional expansion, potentially impacting the acrylic resin's ability to maintain its dimensions stably. The outcomes of our study regarding water absorption were in line with those documented by [PERSON] et al. [66]. They indicated that water uptake in the thermoplastic category was notably lower compared to the control group of PMMA. Furthermore, another researcher [67] highlighted notable distinctions in water absorption among six thermoplastic resins and a conventional PMMA, barring one polyamide resin (Lucitone), which displayed higher water absorption surpassing the maximum ISO standard water absorption values for denture base materials set at 32 ug/mm\({}^{3}\)[68]. This specific material offers relief from denture-related discomfort owing to its strong flexural attributes and adaptability, ensuring it remains secured in the indentations of the remaining teeth. Moreover, the decreased water absorption and solubility of these thermoplastic resins broaden their range of applications, positioning them as a viable substitute for conventional PMMA acrylic resins in the context of denture base materials. In addition, it becomes imperative that the flask containing the assembled denture is subjected to elevated temperatures (a minimum of 120 \({}^{\circ}\)C) to eliminate hygroscopic moisture [69]. This, in turn, would avert the detrimental effects of released gases on the product's surface. The integration of a ventilation system is advisable to facilitate the expulsion of gases from the mold cavity during the injection molding procedure [70]. Whenever feasible, it is recommended to apply pastes or coatings to the contact surfaces of the mold cavity before the injection molding process. Elevating the flask and plaster's temperature will inevitably decelerate the polymer's hardening process, resulting in the creation of longer macromolecules [71; 72; 73].