Surface hardness and roughness in glass fiber-modified polymethyl methacrylate resin: An in vitro study

Conventional polymethyl methacrylate denture base resin exhibits inadequate surface hardness and increased surface roughness, affecting durability and promoting microbial colonization. Therefore, it is of interest to evaluate the effect of different glass fiber forms on surface hardness and roughness of heat-cured polymethyl methacrylate. Hence, eighty specimens were divided into four groups (n=20): control, woven fiber, chopped fiber and longitudinal fiber reinforcement (2.5 wt %) and tested using Vickers microhardness and profilometry. Longitudinal fiber reinforcement showed the highest surface hardness (20.99 ± 0.28 VHN), while woven fibers produced significantly greater surface roughness compared to control (p < 0.001). Thus, we show that glass fiber reinforcement improves hardness but increases roughness, with longitudinal fibers providing the most favorable balance for clinical application.