Impact of plant fiber reinforcement on mechanical properties of PMMA denture base resin: a systematic review

Introduction: To improve the clinical outcomes and long-term durability of polymethyl methacrylate (PMMA) denture-based resins, they have undergone several developments and changes in their chemical composition to enhance their mechanical properties, including reinforcing them with natural fibers. Aim: This systematic review aimed to explore the influence of plant fiber reinforcement on the mechanical characteristics of PMMA denture resins. Material and methods: For this purpose, the formulated focus question was ‘Does incorporating plant fibers in PMMA denture resins improve their mechanical strength?’ Using the PRISMA protocol, three electronic databases (Google Scholar, PubMed, and ScienceDirect) were searched using the specific search words: (plant fibers, natural fibers, and PMMA) denture base resins between 2014 and 2024. After evaluating the papers against the inclusion criteria, only those that met all requirements were included in the study. Additionally, all articles were screened for quality assessment, with particular attention to potential bias arising from experimental design and methodological reporting. Results: This review included eight experimental laboratory-based studies that met the inclusion criteria. All studies had low risk of bias, except one, which had moderate risk of bias. The evaluation of reinforced resins’ flexural strength was a noticeable trend observed in studies, with the maximum weight percentage utilized in the studies being 10 wt%. While flexural strength was primarily assessed by the majority of studies, other mechanical properties – including hardness, impact strength, tensile strength, and compressive strength – were also evaluated. Conclusions: The analysis revealed that the flexural strength and surface hardness of PMMA denture resins were significantly enhanced through the addition of plant fiber reinforcement. However, limited and inconclusive data are present for other mechanical properties (impact, compressive, and tensile strength). Extended experimental studies related to aging and various storage protocols, as well as clinical trials, are essential to determine its clinical relevance and longevity