Reinforcement of resin based cement with titania nanotubes

Objective. One of the limitations of resin cements and flowable dental composites is their poor mechanical properties such as low flexural strength and fracture resistance under body conditions. The present study was performed to enhance the mechanical properties of commercial acrylic cement (CMW (R) 1) by introducing novel nanostructured titania tubes (n-TiO2 tubes) into the cement matrix, with the tubes acting as a reinforcing phase. The long term objective is to add these fillers as reinforcement to dental resin cements and flowable composites in combination with existing fillers. Methods. The surface of the n-TiO2 tubes was modified using a bi-functional monomer, methacrylic acid. The n-TiO2 tube content of the cement was varied from 0 to 2 wt.%. The following cement properties were investigated: maximum polymerization temperature (T-max), dough time (t(dough)), setting time (t(set)), complex viscosity-versus-time, radiopacity, fracture toughness (K-IC), flexural strength (FS), flexural modulus (FM) and in vitro biocompatibility. Results. Based on the determined mechanical properties, the optimized composition was found at 1 wt.% n-TiO2 tubes, which provided a significant increase in K-IC (73%), FS (42%) and FM (56%). However the rheology, radiopacity and biocompatibility were not different from the control (CMW (R) 1). Significance. Enhanced interaction and strong adhesion between the functionalized n-TiO2 tubes and polymer matrix allows external mechanical stress to be more effectively transferred through the filler-matrix interface. This novel filler in conjunction with the existing ones can be used to reinforce orthopedic and dental cements as well as flowable dental composites without altering the rheology, radiopacity and biocompatibility. (C) 2009 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.