Comparative Evaluation of Two Different Preparation Designs and Materials on the Fracture Resistance of Laminate Veneers: An In Vitro Study.

Introduction Laminate veneers are thin porcelain or composite resin shells bonded to the front of teeth for cosmetic enhancement. The design of the tooth preparation is crucial; it involves minimal enamel removal to ensure a proper fit and strong bond. This careful preparation increases the veneers' fracture resistance by preserving tooth structure and evenly distributing stress, ensuring durability and natural appearance. Aim Our aim was to determine the fracture resistance of two preparation designs with two different materials for the fabrication of laminate veneers. Materials and methods An in vitro study was conducted on 40 laminate veneers divided into two groups based on the material used: Group 1 (Cerec Tessera (Dentsply Sirona, Charlotte, NC, USA)) and Group 2 (Upcera, Shenzhen, China). Each group was further divided into two sub-groups based on tooth preparation designs: butt joint and feather edge. The fracture resistance of these veneers following thermocycling was determined, and the mode of fracture was evaluated using a stereomicroscope. Results Feather edge preparation with Cerec Tessera laminate veneer restoration demonstrated the highest fracture resistance at 111.5 N, followed by butt joint preparation with Cerec Tessera laminate veneer restoration, which showed a fracture resistance of 90.8 N. The study identified laminate fractures as the most common type of fracture observed in the veneer restorations, followed by cement interface fractures. Conclusion The study suggests that the feather edge preparation design contributed to higher fracture resistance compared to the butt joint design. This finding aligns with the idea that modifying the preparation design can have a significant impact on the overall strength and durability of veneer restorations. The use of Cerec Tessera, especially in combination with the feather edge design, yielded the maximum fracture resistance.