Effect of virtual cement space and restorative materials on the adaptation of CAD-CAM endocrowns

Abstract

Background This study aimed to evaluate the effect of virtual cement space and restorative materials on the fit of computer-aided design and computer-aided manufacturing (CAD-CAM) endocrowns. Methods A mandibular first molar tooth model received a butt joint margin endocrown preparation with a 2-mm occlusal thickness. Then, using a 3D-printing system, 120 copies of this prepared die were printed and assigned equally to three groups with different cement space settings (30, 60, and 120 μm) during the chairside CAD design. In the milling process, CAD-based models with a particular space setting were subdivided into four groups (n = 10) and fabricated from different CAD-CAM materials: Vita Suprinity (VS), Celtra Duo (CD), Lava Ultimate (LU), and Grandio blocs (GR). Finally, the endocrowns were stabilized over their corresponding models with siloxane and subjected to micro-computed tomography to measure the fit. Results The cement space that was predesigned at 30 μm generated the largest marginal discrepancy (from 144.68 ± 22.43 μm to 174.36 ± 22.78 μm), which was significantly different from those at 60 μm and 120 μm (p < 0.001). The combination of VS or CD with a pre-setting cement space of 60 μm and the combination of LU or GR with a cement space of 120 μm showed better agreement between the predesigned and actual measured marginal gap widths. For internal adaptation, only the cement space set to 30 μm exceeded the clinically acceptable threshold (200 μm). Conclusions The setting of the cement space and restorative material significantly affected the marginal adaptation of CAD-CAM endocrown restorations. Considering the discrepancy between design and reality, different virtual cement spaces should be applied to ceramic and resin composite materials.

Application of one-piece endodontic crowns fabricated with CAD-CAM system to molars

“…Numerous articles reported that they were within these ranges regardless of the material types of CAD-CAM endocrowns ( Table 1 ). One of the causes of the clinically unacceptable range may have been the influence of setting of the space between restoration and cement when fabricated with the CAD-CAM system [79] .…”

Evaluation of Diverse Digital Impression Systems on the Three-Dimensional (3D) Fit of All-Ceram CAD/CAM Crowns

“…It should be noted that the measurement of marginal and internal deviation before cementation provides useful information for evaluating the accuracy of intraoral scans and subsequent crown fabrication. However, the results of this study cannot really be applied to a clinical scenario because cementation would introduce other factors that could influence the marginal and internal fit of All-Ceram CAD/CAM crowns, such as the luting agent (31), as well as the applied seating force (32) are factors that influence the final Three-Dimensional gap.…”

The effect of preparation design on the fracture resistance and adaptation of the CEREC ceramic endocrowns

“…To ensure that all fabricated endocrowns were identical, using the biogeneric mode design, the original anatomy produced by the software was used. For all restorations, at least 2 mm occlusal thickness at the reduced walls were considered (Zhang et al, 2022 ) along with a 60 mm cementing space (Zheng et al, 2022 ). Each wall's thickness was measured using the cursor detail tool, and subtle modifications were made to preserve the anatomy while maintaining a minimum thickness of 2 mm for each wall.…”