Effects of thickness, processing technique, and cooling rate protocol on the flexural strength of a bilayer ceramic system.

Objective: To determine whether the thickness, processing technique, and cooling protocol of veneer ceramic influence the flexural strength of a bilayer ceramic system.

Materials And Methods: Sixty-four bar-shaped specimens (20mm×4mm×1mm) of yttria-stabilized tetragonal zirconia (Vita In-Ceram YZ, Vita) were fabricated (ISO 6872) and randomly divided into 8 groups (n=8) according to the factors "processing technique" (P - PM9 and V - VM9), "thickness" (1mm and 3mm), and "cooling protocol" (S - slow and F - fast). The veneer ceramics were applied only over one side of the bar-shaped specimens.