Effect of thermomechanical aging on marginal fit of three CAD-CAM restorative materials: An in vitro study

Background: The present study assessed the impact of thermomechanical aging on the marginal fit of hybrid ceramic, reinforced composite resin, and lithium disilicate ceramic.

Methods: Eighteen human upper first premolars freshly extracted for orthodontic purposes were used to fabricate 18 CAD-CAM veneers and divided into three groups based on materials used: group H (n=6): hybrid ceramics (Vita Enamic), group R (n=6): reinforced composite resin (Brilliant crios), and group L (n=6): lithium disilicate ceramic (IPS e-max CAD). Each material's cementation procedure was carried out according to the manufacturer's instructions. The vertical marginal gap between the laminate veneer margin and the prepared tooth finish line was measured to assess the specimens by digital microscopy. Subsequently, all the samples were thermomechanically cycled (TMC) (5 °C to 55 °C, 30 seconds, 75000 cycles). Then, the vertical marginal gap was re-evaluated.

Results: The Brilliant crios group displayed a significantly lower vertical marginal gap mean score (31.36±2.82 µm) followed by Vita Enamic (39.27±6.54 µm) and E max (41.39±3.97 µm) groups. Similarly, after thermomechanical aging, the Brilliant crios group displayed a significantly lower vertical marginal gap mean score (41.83±8.28 µm) followed by Vita Enamic (55.47±18.65 µm), and the E max group showed the greatest vertical marginal gap mean score (59.43±16.27 µm).

Conclusion: Thermomechanical aging affected the marginal fit of different materials employed in the current research, and these changes were under the established clinical limit.