Objectives: To evaluate the marginal adaptation of premolar monolithic ceramic crowns fabricated from novel advanced lithium disilicate CAD/CAM blocks with two different finish line designs (feather edge finish and deep chamfer finish lines), both before and after exposure to thermomechanical aging.
Materials & methods: Twenty-two maxillary premolar teeth were endodontically treated, and divided into 2 groups according to finish line design; deep chamfer finish line (Gr_C) group (n=11), and feather-edge finish line (Gr_V) group (n=11). Following teeth preparation, all crowns were milled from advanced lithium disilicate CAD/CAM blocks (CEREC Tessera) and adhesively bonded to their corresponding teeth using adhesive resin cement then, subjected to thermomechanical aging. Marginal gap was assessed using digital microscope and image analysis software.
Results: feather-edge finish line showed the lowest marginal gap mean values (29.07± 8.05), while deep chamfer finish line recorded the highest marginal gap mean values after artificial aging (52.97± 2.79). The results were statistically significant before artificial aging, but non-significantly different after thermal cycling.
Conclusion: Advanced lithium disilicate (CEREC Tessera) monolithic crowns with feather-edge margins showed superior margin adaptation to those fabricated with deep chamfer margins and can offer a more conservative solution for reconstruction of severely compromised teeth.