Damping and mechanical behavior of metal-ceramic composites applied to novel dental restorative systems.

Conversely to natural teeth, where periodontal ligament (PDL) and pulp works as a damper reducing the effect of the stress on surrounding structures, when natural teeth is lost and replaced or restored the biting forces are directly transmitted to the bone or affect the integrity of the adjacent bottom layers. In this study, damping capacity and dynamic Young's modulus of CoCrMo-porcelain composites for dental restorations were evaluated. Dynamic Young's modulus and damping capacity of materials were assessed by dynamic mechanical analyzes (DMA) at 1 and 10 Hz frequencies, over a temperature ranging (18-60 °C). Results show that by reinforcing dental porcelain with metallic particles, producing ceramic matrix composites (CMCs) with 20 vol% and 40 vol% of metallic particles, the damping capacity and dynamic Young's modulus are improved. A decrease on both properties of the metal matrix composites (MMCs) with increasing ceramic particles content (from 20 vol% to 40 vol% of ceramic phase) was observed for all the studied frequencies and temperatures. While damping capacity is strongly dependent on frequency, no significant difference in dynamic Young's modulus was found. Results show that besides the yet reported advantages of the bio-inspired functionally graded restorations over traditional bilaminate ones, traduced by improved veneer to substrate adhesion and by the enhanced thermal and mechanical stress distribution, these restorations can also display improved behavior as regard to a damping capacity, which may have a positive impact in the long-term performance of implant - supported prosthesis.