Influence of Heat Treatment on Dental Prostheses Produced by Additive Technology

Heat treatment process represents an important part of metal-ceramic dental prostheses production process. The presented paper deals with the influence of heat treatment on the geometry of dental prostheses manufactured using SLM additive technology. Dental prostheses (crowns, two-unit bridges, thee-unit bridges) made from cobalt-chromium alloy on the device Mlab cusing R (Concept Laser, USA) via SLM technology. to-piece batch from each type of prostheses were produced. Subsequently, the pre- and post-heat treatment change in prosthesis geometry compared against the original.stl model was examined using GOM Inspect software (GOM, Germany). Crowns and two-unit bridges did not meet the normality requirement, therefore a non-parametric t-test (Wilcoxon test) was applied for variation comparison. Three-unit bridges met the normality criterion, therefore a parametric t-test was used to identify statistically relevant variations in dependent samples. Based on the results, we may conclude that the crowns and two-unit bridges manufactured via SLM technology do not change their geometry prior to or following the heat treatment. Three-unit bridges undergo geometry changes, therefore the heat treatment must be performed before the bridges are removed from a manufacturing platform.