Micro-scale abrasion wear of novel biomedical PEEK-matrix composites for restorative dentistry

Novel PEEK-based composites have been studied to replace metallic biomedical implant and prostheses although the influence of aggressive oral conditions should be understood such as wear in the presence of toothpaste abrasive particles. The main aim of this study was to assess the micro-abrasion performance of novel PEEK-based composites embedding biocompatible inorganic fillers composed of (LZSA) lithium-silicate glass ceramic or (NASF) natural silica fibers. PEEK powders were mixed with 10 and 30 wt% LZSA or NASF to produce composite structures by using hot pressing technique. After polishing and cleaning procedures, test surfaces were assessed by micro-scale abrasion tests at on 0.8 N at 600 ball revolutions in contact with an abrasive suspension of 6 wt% amorphous silica particles with mean size at 8-10 μm. The worn and unworn surfaces were inspected by scanning electron microscopy (SEM) and optical profilometry. SEM images revealed aligned abrasion grooves on all the test surfaces. The largest damaged area was noticed on PEEK free of inorganic fillers while the lowest micro-abrasion damage was recorded on PEEK embedding 10%LZSA. The micro-abrasion resistance of PEEK-LZSA composites was negatively affected by the increase of inorganic content as seen on 30%LZSA. However, PEEK-based composites showed a higher micro-abrasion wear resistance than that on non-reinforced PEEK. The wear resistance can be enhanced by adding an adequate content and shape of inorganic fillers. Further studies should investigate the effect of morphology and properties of inorganic fillers to improve the wear performance of PEEK-based composites.