Internal and marginal discrepancies of monolithic zirconia, polymer infiltrated ceramic, and lithium disilicate crowns: an in vivo study.

Evaluate the marginal and internal discrepancies of Lithium Disilicate (LD), Monolithic Zirconia (Zr), and Polymer-Infiltrated Ceramics (PIC) crowns in vivo. Thirty patients requiring posterior single crowns were divided into three groups (n = 10 each): LD (IPS e.max CAD), Zr (Zircon Fit Plus), and PIC (VITA Enamic). After tooth preparation and temporary crown placement, impressions were taken for the fabrication of the crown. Marginal (MD) and Internal (ID) Discrepancies were measured before cementation using the replica technique and optical stereomicroscopy. ID was assessed by measuring the light body silicone thickness in occlusal, cusp, axial, and chamfer regions, while MD was evaluated at the chamfer finish line. ID was analyzed by two-way ANOVA and Tukey tests, while MD was analyzed by one-way ANOVA (α=5%). For ID, ANOVA revealed that the factors "material", "region", and their interaction were significant (p < 0.05). Although ID values varied by material and region, all remained within clinically acceptable limits. When comparing the experimental groups, PICo (226.0±84.7A μm) and PICc (165.6±71.9AB μm) exhibited the highest ID values, while LDax (87.9±17.3D μm) and PICax (91.4±36.2D μm) had the lowest. For MD, ANOVA revealed no significant differences between the materials (p = 0.4287): Zr (108.4 ± 34.6 μm), LD (95.7 ± 13.6 μm), and PIC (114.5 ± 42 μm). ID and MD were comparable among the evaluated crown materials, with all values falling within clinically acceptable limits. However, the lack of reported acceptable clinical thresholds and limited sample size highlight the need for larger-scale studies and long-term follow-ups to assess the longevity of restorative treatments.