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Objective: To compare the bond strength of monolithic CAD-CAM materials to resin cement using different surface treatment methods. Materials and Methods: Lithium disilicate glass ceramic (IPS e-max CAD), zirconia-reinforced lithium silicate ceramic (Vita Suprinity), resin nanoceramic (Lava Ultimate), and hybrid ceramic (Vita Enamic) were used. Five groups of CAD-CAM blocks were treated as follows: control (C), HF etching (HF), HF etching + silanization (HF + S), sandblasting (SB), and sandblasting + silanization (SB + S). After surface treatments, SEM analyses were conducted. Specimens were cemented with self-adhesive resin cement (Theracem) and stored in distilled water at 37°C for 24 h. Shear bond strength (SBS) was measured, and failure types were categorized. Results were analyzed using two-way ANOVA and the post-hoc Tukey test. Results: Statistical analysis revealed significant differences between SBS values obtained for different surface treatments and CAD-CAM block types ( P < .001). Among the CAD-CAM materials, the highest SBS was reported in the HF + S group for Vita Enamic. Although IPS e.max CAD, Vita Suprinity, and Vita Enamic showed higher bond strength when treated with HF + S, Lava Ultimate has the highest bond strength value when treated with SB + S. Conclusions: The bond strength of CAD-CAM materials was influenced by surface treatment. Additionally, silanization significantly improved the bond strength of all materials except Lava Ultimate.

Objective. The purpose of this study was to examine the optical properties of translucent zirconia with different thickness during multiple firings. Materials and Methods. Three different types of translucent zirconia (Vita YZ HT (HT), Vita YZ ST (ST), Vita YZ XT (XT)) with thickness of 0.5, 1, and 1.5 mm were used in the study. 180 disk-shaped specimens ( n = 10 ) were prepared from preshaded and nonshaded blocks. The coloring liquid (A2, Vita Shade Liquid) was applied with a synthetic nylon brush in the nonshaded group. Then, the specimens were then subjected to 1, 3, and 5 firing times. After consecutive firings, color differences ( Δ E ) and translucency parameter ( TP ) were measured. Statistical analysis was carried out by using repeated measure ANOVA followed by Tukey test. Results. ANOVA analysis reveals that TP and Δ E were significantly affected by the repeated firings. The highest TP was seen in 0.5 mm XT specimen. For all specimens, TP decreases from 1st to 3rd firing cycles, despite TP increases from 3rd to 5th firing cycles. Although there is a significant change in TP values in 0.5 mm thickness, there is no significant change between firing cycles for 1 and 1.5 mm thickness specimens. The highest Δ E value was observed for shaded specimens between 1st and 5th firings. Δ E values were not significantly different between 1 and 3 firings. Conclusions. Changes in thickness and repeated firings of zirconia specimens affected final color and translucency of zirconia specimens. HT blocks are more affected by consecutive firings than ST and XT blocks. Δ E increased as the thicknesses decreased for both types of translucent zirconia specimens tested.