Physical and Mechanical Properties of PMMA Bone Cement Reinforced with Nano-sized Titania Fibers

Abstract

X-ray contrast medium (BaSO4 or ZrO2) used in commercially available PMMA bone cements imparts a detrimental effect on mechanical properties, particularly on flexural strength and fracture toughness. These lower properties facilitate the chance of implant loosening resulting from cement mantle failure. The present study was performed to examine the mechanical properties of a commercially available cement (CMW®1) by introducing novel nanostructured titania fibers (n-TiO2 fibers) into the cement matrix, with the fibers acting as a reinforcing phase. The hydrophilic nature of the n-TiO2 fibers was modified by using a bifunctional monomer, methacrylic acid. The n-TiO2 fiber content of the cement was varied from 0 to 2 wt%. Along with the mechanical properties (fracture toughness ( KIC), flexural strength (FS), and flexural modulus (FM)) of the reinforced cements the following properties were investigated: complex viscosity-versus-time, maximum polymerization temperature ( Tmax), dough time ( tdough), setting time ( tset), radiopacity, and in vitro biocompatibility. On the basis of the determined mechanical properties, the optimized composition was found at 1 wt% n-TiO2 fibers, which provided a significant increase in KIC (63%), FS (20%), and FM (22%), while retaining the handling properties and in vitro biocompatibility compared to that exhibited by the control cement (CMW®1). Moreover, compared to the control cement, there was no significant change in the radiopacity of any of the reinforced cements at p = 0.05. This study demonstrated a novel pathway to augment the mechanical properties of PMMA-based cement by providing an enhanced interfacial interaction and strong adhesion between the functionalized n-TiO 2 fibers and PMMA matrix, which enhanced the effective load transfer within the cement.