Effect of natural fibers reinforcement on tensile strength of acrylic denture base: In vitro study, sem and x-ray diffraction analysis

The use of acrylic (HCAR) dentures for a long time often causes problems, namely, they are easily damaged or broken. This damage occurs when used due to user negligence. One of the causative factors is the poor nature of acrylic resin (HCAR), especially in terms of impact strength. The method to increase the strength of the acrylic plate is by adding fiber. There are 2 types of fibers known in Dentistry, namely synthetic and natural fibers. Synthetic fibers are relatively more expensive, so the use of natural fibers can be an alternative, for example, ramie and banana stem fibers. This study aims to determine the characteristics of the HCAR denture base reinforced by ramie and banana stem fibers in the form of tensile strength, SEM, and X-ray diffraction and to see a comparison between the control group and the ramie and banana stem fibers groups. Research method in the form of an Experimental Laboratory, a total of 30 samples. The sample is an acrylic dumbbell shape of 75×10×3 mm in accordance with the ISO 527-1 (2019) for the tensile strength test. The concentration of fibers added was 1.6% of the sample weight. The sample consisted of 3 groups, namely control, the addition of ramie fiber, and banana stem fiber. Tensile strength testing used the Universal Testing Machine, followed by SEM and X-ray diffraction. Data were analyzed using the Oneway ANOVA test and the Post Hoc LSD test (p< 0.05). Results: The ramie fiber addition group had the highest tensile strength (70.06 MPa), while the banana stem fiber addition group had the lowest tensile strength (64.98 MPa). There was a significant difference in the control group and the addition of ramie fiber, and ramie fiber and banana stem fiber (p< 0.05). In SEM examination, it can be seen that the fracture edges and rough surfaces and cracks are different for each group and X-ray diffraction analysis shows the same results in all groups. Conclusion: The addition of ramie fiber can increase the tensile strength of the HCAR denture base, but it is different from the addition of banana stem fiber. This is in accordance with the SEM image obtained on ramie fiber, which shows a rough surface and cracks that spread across the fracture surface with solid, converging protrusions and visible cavities formed due to the fibers being pulled out of the matrix.