Correlation of three wear testing methods and surface roughness analysis in 3D-printed crown materials

The objective of this in vitro study was to evaluate and correlate the wear resistance of three additively manufactured dental restorative materials using three wear test methods. ball-on-disc, block-on-ring, and linear reciprocation. Three polished or glazed restorative materials were divided into four groups and subjected to wear testing under 49 N and 70 N loads, submerged in artificial saliva to simulate 48 months of in vivo wear. Vertical loss, step-height, surface roughness and friction coefficient were recorded. Correlation and statistical analyses were conducted. Ball-on-disc and reciprocative methods exhibited an overall weak positive correlation, while reciprocation vs. block-on-ring had weak to negative correlations. Three-way ANOVA indicated a significant effect of material type on vertical loss values (P < 0.03). Reciprocation caused higher surface roughness for Crowntec Plus and VarseoSmile Plus (P < 0.05), but not for MFH C&B (P > 0.05). Friction coefficient remained clinically acceptable across all methods. Increased load (49 N to 70 N) minimally impacted wear but affected surface roughness. Materials exhibited varying wear performance based on the testing method used. Weak correlations were observed across wear tests in most instances, with increases in load having minimal impact on wear outcomes and variable impact on surface roughness depending on the testing method.