Comparison of accuracy of single crowns generated from digital and conventional impressions: An in vivo controlled trial

Aim With the advances of digital technology, intraoral digital impression (DI) technique has become a major trend in prosthodontics with respect to traditional impression (TI) techniques; despite that, very few data are available concerning its accuracy. Thus, the purpose of this study was to compare the effectiveness of DI versus TI considering both marginal and internal gap (MG, IG, respectively) in cobalt-chromium (Co-Cr) single crowns manufactured by mean of computer-aided design and computer-aided manufacturing (CAD/CAM) technology. Material and methods Thirty posterior teeth were considered for this study. For each abutment tooth, sixty and thirty copings were produced with the aid of TI and DI, respectively. Thirty of the sixty copings of the TI-group were then randomly selected to be veneered and cemented onto existing abutments. The space existing between the internal surface of the coping and the abutment tooth was evaluated onto an in vitro replica; the MG and IG were measured by Scanning Electron Microscope. The data were analysed by the Wilcoxon test (1-tailed). Results The mean MG was 75.04 μm (SD = 13.12) and 55.01 μm (SD = 7.01) for the TI group and DI group, respectively. As regards the mean IGs, the values recorded were of 78.36 μm (SD = 19.66) for the TI-group and 59.20 μm (SD=3.33) for the DI-group. A statistically significant difference was found between the two groups (p-value = 0.001). Conclusions Copings manufactured from DI showed better MGs and IGs with respect to copings produced from TI. However, both approaches produced clinically acceptable results