Objectives. To assess energy dissipation capacities and surface damping abilities of different CAD/ CAM restorative materials (CRMs) to characterize stress resistance during load peaks.

Methods. Using instrumented indentation testing (IIT), Martens hardness (HM) together with its elastic (eta(IT)) and plastic index (eta(ITdis)) and Leeb hardness (HLD) together with its deducedenergy dissipation (HLDdis) were determined for eight ceramic, eight composite, and fourpolymer-based materials as well as three metals. The results were compared to those of bovine enamel. Ten indentations per material were performed at room temperature (23 +/- 1 degrees C) on two separate specimens (12.0 x 12.0 x 3.5 mm(3)) after water storage (24 h; 37.0 +/- 1.0 degrees C). Hardness parameters were recorded, and data were analyzed with one-way MANOVA( Games-Howell post hoc tests, alpha = 0.05). Correlations between different parameters were tested (Pearson, alpha = 0.05).

Results. Independently determined HLDdis, and eta(ITdis) values substantiated different energy dissipation characteristics of CRM, whereby a strong correlation was observed for the two datasets (r = 0.956, p = 0.011). Ceramics had the significantly lowest values (p < 0.001) whileboth parameters revealed the highest surface damping effects for metals (p < 0.001), followed in both cases by bovine enamel. Energy dissipation of polymer and composite CRM was in between ceramics and bovine enamel (p < 0.001), whereas only for HLDdis did both show no significant difference (p > 0.05).

Significance. Promising new HLDdis and eta(ITdis) data allow a reliable differentiation of energydissipation and surface damping capacities of CRMs. Previously published rankings of edge chipping and loss tangent results were perfectly reproduced, especially by HLDdis. (C) 2021 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.