Cement Thickness of Inlay Restorations Made of Lithium Disilicate, Polymer‐Infiltrated Ceramic and Nano‐Ceramic CAD/CAM Materials Evaluated Using 3D X‐Ray Micro‐Computed Tomography

Purpose To evaluate the marginal and internal cement thicknesses of inlay restorations made of various CAD/CAM materials using 3D X‐ray micro‐computed tomography (micro‐CT) technique. Materials and Methods Caries‐free extracted mandibular molars (N = 30) with similar size were randomly assigned to three groups (N = 10 per group). Mesio‐occlusal‐distal (MOD) cavities were prepared, and inlay restorations were obtained by milling out CAD/CAM materials namely, (a) IPS: monolithic lithium disilicate (control), (b) VE: polymer‐infiltrated ceramic, and (c) CS: nano‐ceramic using a CAM unit. Marginal and internal cement thicknesses were measured using 3D micro‐CT. Data were analyzed using 1‐way ANOVA and Tukey's tests (alpha = 0.05). Results The mean marginal and internal cement thickness were not significant in all inlay materials ( p > 0.05). Mean marginal cement thickness (μm) was the lowest for the IPS group (67.54 ± 10.16) followed by VE (84.09 ± 3.94) and CS (95.18 ± 10.58) ( p > 0.05). The internal cement thickness (μm) was the lowest in the CS group (54.85 ± 6.94) followed by IPS (60.58 ± 9.22) and VE (77.53 ± 12.13) ( p > 0.05). Conclusion Marginal and internal cement thicknesses of MOD inlays made of monolithic lithium disilicate, polymer‐infiltrated ceramic, and nano‐ceramic CAD/CAM materials were similar and all less than 100 μm, which could be considered clinically acceptable. Clinical significance MOD inlays made of different CAD/CAM materials presented similar cement thickness, less than 100 μm.