Clinical Marginal and Internal Fit of Crowns Fabricated Using Different CAD/CAM Technologies

Purpose The aims of this in vivo investigation were to compare the marginal and internal fit of single‐unit crowns fabricated using a selective laser melting (SLM) procedure with two CAD/CAM grinding procedures, and to evaluate the influence of tooth type on the parameters measured. Materials and Methods A total of 270 crowns were evaluated, including 90 SLM metal‐ceramic crowns (group B), 90 zirconium‐oxide‐based ceramic crowns (group L), and 90 lithium disilicate ceramic crowns (group C). The marginal and internal gaps of the crowns were recorded using a replica technique with a silicone indicator paste stabilized with a light‐body silicone. The gap replica specimen were sectioned buccolingually and mesiodistally and then examined using a stereomicroscope at 30× magnification. Ten reference points were measured on each anterior and premolar specimen, and 20 reference points were measured on each molar specimen. Two‐way ANOVA was performed to identify the significant differences between the groups. Results The mean marginal fit of group B was significantly better than those of group C and group L (p < 0.005), but a significant difference was not found between group C and group L (p > 0.05). The mean axial gap of group B was significantly smaller than those of group C and group L (p < 0.01), while group C was not different from group L (p > 0.05). The mean occlusal gap of group B was significantly higher than those of group C and group L (p < 0.05), and no difference was found between group C and group L (p > 0.05). The marginal and internal gaps of crowns varying according to tooth type were not significantly different (p > 0.05). Conclusion The SLM system demonstrated better marginal and internal fit compared to the two CAD/CAM grinding systems examined. Tooth type did not significantly influence the marginal or internal fit.