SEM Evaluation of the Marginal Accuracy of Zirconia, Lithium Disilicate, and Composite Single Crowns Created by CAD/CAM Method: Comparative Analysis of Different Materials

Abstract

(1) Background: The objective of this in vitro study is to evaluate the marginal accuracy of crowns created by CAD/CAM. (2) Methods: A customized chrome-cobalt (Cr-Co) implant abutment simulating a maxillary right first molar was fixed in a hemi-maxillary stone model and scanned. In total, 27 crowns were fabricated, including 9 lithium disilicate crowns, 9 composite crowns, and 9 zirconia crowns. The measurements were determined by scanning electron microscopy. Descriptive analysis was performed using the mean and standard deviation, while the Kruskal–Wallis test was performed to determine whether the marginal discrepancies were significantly different between each group (p < 0.05). (3) Results: The lowest marginal gap value was reported for zirconia (21.45 ± 12.58 µm), followed by composite (44.7 ± 24.96 µm) and lithium disilicate (62.28 ± 51.8 µm). The Kruskal–Wallis tests revealed a statistically significant difference (p-value < 0.05) in the mean marginal gaps between different materials. (4) Conclusions: The proposed digital workflow can be a viable alternative for fixed prosthetic rehabilitations. The best performance in terms of marginal gap was achieved by zirconia crowns, but all three materials demonstrate marginal closure below the clinically accepted threshold value (120 µm). Clinical significance: although significant differences were reported, the investigated CAD/CAM materials showed clinically acceptable marginal gaps.

SEM Evaluation of the Marginal Gap of Zirconia-Reinforced Lithium Silicate Full Crowns and the Effect of Post Crystallization: An In Vitro Study

“…The results of the zirconia are similar to the results of the pre-crystallization ZLS in our study (24.25 ± 5.49 μm), and the results of the lithium disilicate are similar to the results of post-crystallization ZLS in our study (79.82 ± 7.86 μm). As ZLS is a glass-based material with zirconia particles, it is very interesting that our results before and after crystallization are similar to zirconia and lithium disilicate, respectively [ 38 ].…”

Laser debonding of ultrathin occlusal veneers fabricated from different CAD/CAM ceramic materials

“…The marginal accuracy of the restoration can affect the volume of cement used consequently affecting the debonding time. Marginal accuracy is affected by many factors including the milling process [ 45 ]. Significant differences in marginal fit were observed between three materials milled using a 3-axis milling machine [ 45 ].…”

“…Marginal accuracy is affected by many factors including the milling process [ 45 ]. Significant differences in marginal fit were observed between three materials milled using a 3-axis milling machine [ 45 ]. Another study compared the marginal fit of lithium disilicate and zirconia using a 3-axis milling machine and a 5-axis milling machine.…”

“…This promotes a more accurate marginal fit that results in less cement volume. Other factors that may affect the marginal accuracy include the preparation design and the scanning method used [ 45 ]. In our study, the design was standardized, and the same scanner was used in all groups.…”

Clinical outcomes of self-glazed zirconia veneers produced by 3D gel deposition: a retrospective study

“…The fabrication of fixed dental crowns and bridges encompasses both subtractive and additive manufacturing methods, each offering unique advantages in the production process. Subtractive techniques involve the precise removal of material from solid blocks using milling machines, allowing for meticulous sculpting of dental materials such as ceramics or hybrid materials [ 15 , 16 ]. Conversely, additive manufacturing, also known as 3D printing, builds up material layer by layer guided by computer-aided design (CAD) software, facilitating the creation of intricate and personalized restorations [ 17 ].…”