The purpose of this study was to investigate and compare the marginal and internal fit of ceramic inlays made by slurry molding, heat-pressed and computer aided design/computer aided manufacturing (CAD-CAM) techniques restoring the cavities with the same figuration and size.

The material of the sample was organic glass. Thirty samples were prepared into standard cavities using computer numerically controlled system and assigned to three groups (n = 10 each) according to different processing techniques and materials using a random number table method. The In-Ceram Spinell group was restored with In-Ceram Spinel inlays made by slurry molding technique, while the IPS e.max Press group was restored with IPS e.max Press inlays made by heat-pressed technique and the Cercon Zirconia group was restored with Cercon Zirconia inlays made by CAD-CAM technique. Scanning electron microscope (×300 magnification) was used to observe the edge morphology of inlays and measure the gaps between the inlay and cavity. The data were analyzed using SAS, and the inter-group comparison was examined by LSD-t test.

All of the inlays showed smooth surfaces. The even and smooth surface and integrated margin were obtained in Cercon Zirconia group. The internal gap (IG) of the three groups, In-Ceram Spinell group: (94 ± 41) μm; IPS e.max Press group: (64 ± 20) μm and Cercon Zirconia group: (72 ± 25) μm, were less than 120 μm. The marginal gap (MG) , (100 ± 37) μm, and the absolute marginal discrepancy (AMD) , (119 ± 38) μm, of Cercon Zircon group were less than 120 μm. There were no statistically significant differences between IPS e.max Press and Cercon Zirconia group (t_IG = 0.8410, P_IG = 0.4114, t_MG = 1.499, P_MG = 0.1512, t_AMD = 1.630, P_AMD = 0.1206) . Statistical difference was found in IG between In-Ceram Spinell and IPS e.max Press group (t = 2.146, P = 0.0457) , as well as in AMG (t = 2.305, P = 0.0333) between In-Ceram Spinell and Cercon Zirconia group.

The In-Ceram Spinell, IPS e.max Press and Cercon Zirconia inlays fabricated by different processing techniques provided clinically acceptable marginal and internal fit. The Cercon Zircon inlay made by CAD-CAM technique showed better results than the IPS e.max Press and the In-Ceram Spinell inalys.