Two-Body Wear of CoCr Fabricated by Selective Laser Melting Compared with Different Dental Alloys

The purpose of this study was to assess the two-body wear of cobalt-chromium (CoCr) samples fabricated by selective laser melting (SLM) in contrast to cast samples and enamel. The following materials were chosen for comparison with SLM-CoCr: a CoCr alloy for use in the lost-wax technique, four gold alloys with different hardness, titanium (grade 1), and human enamel. Seven specimens of diameter 12 mm and thickness 1 mm were produced from each material and polished with emery paper. Al2O3 ceramic balls served as antagonists in the biaxial chewing simulator. Multiple chewing cycles were applied with a static load of 50 N. Wear was analysed laser-optically by the use of cast replicas. Statistical analyses were performed with Kruskal-Wallis test and subsequent post hoc Mann-Whitney U tests at a significance level of 0.05. SLM-CoCr showed less wear than any of the other materials. The difference was statistically significant between SLM-CoCr (vertical loss -54.4 +/- 6.9 mu m after 300,000 cycles) and cast CoCr (vertical loss -117.2 +/- 18.6 mu m after 300,000 cycles). Greatest vertical wear was observed for titanium. SLM-CoCr exhibits a great resistance to wear and might represent an alternative for the manufacture of prosthetic restorations even in occlusal loading areas. Clinical relevance Clinical investigations on wear of SLM-CoCr are needed to assess its in vivo behaviour.