Influence of monolithic lithium disilicate and zirconia thickness on polymerization efficiency of dual‐cure resin cements

Objective To evaluate the influence of anterior monolithic zirconia and lithium disilicate thickness on polymerization efficiency of dual‐cure resin cements. Materials and Methods Twelve ceramic disks (4.0‐mm diameter) with thicknesses of 0.5, 1, 1.5, 2, 2.5, and 3 mm were prepared from monolithic zirconia (Prettau® Anterior; n = 6) and lithium disilicate (IPS e.max® CAD HT; n = 6). Three dual‐cure resin cements (Panavia F 2.0, DuoLink Universal™, and RelyX™ U200) were used for polymerization beneath ceramic disks. For each resin cement, 10 specimens were prepared by light curing under monolithic zirconia and lithium disilicate disks of each thickness. Vickers hardness measurements were conducted at four different measurement depths. Data were statistically analyzed using univariate four‐, three‐, two‐, and one‐way analysis of variance and independent samples t‐tests. Results Microhardness of resin cements decreased significantly with increasing measurement depth and thickness of monolithic zirconia or lithium disilicate (P