Tensile, Flexural and Hardness Properties of Guava Leaves (Psidil guajava) Extract Modified Coconut (Cocos nucifera) Shell Powder-Polymethyl Methacrylate Base Denture Composites

Denture wearing requires loss of teeth through trauma or natural phenomena. The activation of polymerization of polymethyl methacrylate (PMMA) denture base material by methylmethaacrylate (MMA) caused cytotoxic effect and biofilm formation at undercut hindered the mechanical properties and durability of denture. In this study, the effect of guava leaf extract modified coconut shell powder on mechanical properties of hybrid CSP-PMMA denture base composites was investigated. The coconut shell powder (CSP) was obtained from its extracted fiber after dried, grinded and sieved using 80 μm. Guava leaf extract was obtained using ethanolic method. PMMA composites were prepared at variable weight fraction of PMMA+CSP: GLE+MMA using rule of mixture in ratio. The flexural strength, tensile strength, hardness, and toughness properties of the composites at different levels were determined using Universal testing machine of AMETEK EZ 250 model and a shore scale D durometer in accordance with ASTM D – 2240, respectively. The modification of CSP-PMMA by GLE improved the tensile strength, toughness, elongation and hardness by 18.23, 10.52, 68.14 and 1.35 %. Hence the use of GLE in PMMA denture base composites not only enhanced the mechanical behaviours but protect the PMMA denture against biofilm formation. Keywords: Mechanical properties; Guava leave extract, PMMA; Coconut shell fillers.