Non-Invasive Digital Technique for Examination of Marginal and Internal Adaptation of Different Ceramic Table-Tops

Background: Lacking of proper marginal adaptation of occlusal table-tops resulted in plaque accumulation, and subsequent caries progression.Aim of the study: To evaluate the effect of various restorative CAD/ CAM materials on the marginal and internal adaptation of table- tops using digital method.Materials and methods: Sixty-eight human mandibular first molars were prepared to receive table-top. The restorations were divided into 4 groups according to CAD/CAM materials (n=17): Group (ED) Lithium disilicate; group (CD) Zirconia reinforced lithium silicate; group (PZ) High translucent zirconia; and group (LU): Resin nano- ceramic. The prepared teeth were scanned, designed table-top and cement gap setting of 30µm at margin and 50µm internally were saved, the restorations were milled. A layer of light body silicone replica placed on the intaglio surface of each table-top and adapted over corresponding prepared tooth; re-scanning the prepared teeth with replica. Geomagic software was used for superimposition of STL files (with and without replica; double scan technique), the thickness of the replica were calculated and compared to the previous cement gap setting.Results: Marginal and internal gaps were statistically significant different from the cement setting in group ED, CD and PZ (p ≤ 0.05) when compared with the LU group, the LU group showed the least mean marginal and internal gap values (43.64, 72.95) that were the closest to the cement gap setting.Conclusions: Hybrid ceramics LU showed the lowest marginal and internal discrepancies. The marginal and internal gap values were within the clinically acceptable range except with group ED