Energy dissipation capacities of CAD-CAM restorative materials: A comparative evaluation of resilience and toughness

A study by

• Thomas Niem, PhD, Head, Dental Materials Unit, Department of Prosthodontics, Justus-Liebig University, Giessen, Germany.
• Nivin Youssef, Research Assistant, Department of Prosthodontics, Justus-Liebig University, Giessen, Germany, and
• Bernd Wöstmann, DMD, Professor and Chairman, Department of Prosthodontics, Justus-Liebig University, Giessen, Germany

Conclusion
Based on the results of the present in vitro study, the following conclusions were drawn:

1. All investigated properties were affected by the type of CAD-CAM restorative material.
2. Alphador had the highest mean values for the modulus of toughness, elastic recovery, and the difference between elastic recovery and modulus of resilience and therefore the highest capacity to dissipate destructive fracture energy.
3. Lower mean values of the modulus of toughness and elastic recovery account for the inferior energy dissipation capacities of Lava Plus as compared with Alphador.
4. All modulus of toughness values of the polymerbased CAD-CAM materials and Lava Plus were significantly higher than those of IPS e.max CAD, VITA ENAMIC, and CEREC Blocs, implying a higher capacity to consume destructive energy before material rupture occurs.
5. From an energy dissipation capacity point of view, polymer-based CAD-CAM restorative materials seem to be clinically promising, with considerable robustness and the potential for improvement for additional indications.

Published in THE JOURNAL OF PROSTHETIC DENTISTRY

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