Hardness and young's modulus determined by nanoindentation technique of filler particles of dental restorative materials compared with human enamel

TLDR

This technique eliminates the need to visualize indentations. The recently developed nanoindentation technique measures hardness and Young's modulus of small filler particles in resin composites and other dental restoratives by continuously monitoring load and displacement during a loading–unloading sequence, calculating values from load–displacement curves while accounting for indenter geometry, and applying this method to thirteen posterior composites, three CAD/CAM ceramics, one sintered porcelain, and one amalgam, with results compared to human enamel. Only five tested materials have inorganic filler particles with nanohardness comparable to enamel; the predominant fillers in all other materials, except amalgam and Bell Firm PX prepolymerized resin fillers, were significantly harder, and while most restorative materials (excluding amalgam's alloy phase) had a Young's modulus lower than enamel, the amalgam alloy phase matched enamel's modulus. © 1993 John Wiley & Sons, Inc.

Abstract

Abstract The recently developed nanoindentation technique was used to measure hardness and Young's modulus of small filler particles in resin composites and other dental restoratives. This technique eliminates the need to visualize indentations. Load and displacement are continuously monitored during a loading–unloading sequence, and hardness as well as Young's modulus are then calculated from the load–displacement curves taking into account the geometry of the indenter. Thirteen posterior composites, 3 dental ceramics for CAD/CAM restorations, 1 sintered porcelain, and 1 amalgam were investigated in this study. The results were compared to the hardness and Young's modulus determined by nanoindentation of human enamel. Of the dental materials tested, only five materials contain inorganic filler particles with a nanohardness not statistically different from that of enamel. The predominant fillers in all other materials, except amalgam and the prepolymerized resin fillers in Bell Firm PX, were found to be significantly harder. The dental restorative materials, except the alloy phase in amalgam, were composed of particles with a Young's modulus significantly lower than that of human enamel. The alloy phase in amalgam had a Young's modulus value comparable to that of enamel. © 1993 John Wiley & Sons, Inc.