Clinical evaluation of the fit of lithium disilicate crowns fabricated with three different CAD-CAM systems

Statement of problem: The fit and performance of prostheses fabricated using various computer-aided design and computer-aided manufacturing (CAD-CAM) systems have been evaluated. However, most studies were conducted in vitro, and relatively few have addressed gingival parameters and prosthesis fit under clinical conditions. Purpose: This clinical study aimed to compare the fit of lithium disilicate crowns produced using 3 CAD-CAM systems and evaluate clinical results up to 6 months after delivery. Material and methods: Forty participants requiring a single crown were recruited. Three monolithic lithium disilicate crowns were fabricated per participant by using 3 different CAD-CAM systems (intraoral scanners, CAD software, and milling machines): CEREC group (CEREC Bluecam, CEREC AC, CEREC MC); EZIS group (EZIS PO, EZIS VR, EZIS HM); and TRIOS group (TRIOS 3, EXO-CAD, ARUM-4X). The fit of the prostheses was assessed via a silicone replica technique, and the most acceptable crown was delivered; 12 were selected from the CEREC group, 16 from the EZIS group, and 12 from the TRIOS group. Follow-up clinical examinations were performed at 1, 3, and 6 months after delivery. The Kruskal-Wallis test with the post hoc Mann-Whitney U test was conducted to analyze significant differences in crown fit and periodontal conditions among the groups (α=.05). Results: The marginal gap of the CEREC group was significantly higher than that of the EZIS group, and the occlusal gap of the EZIS group was significantly lower than those of the CEREC and TRIOS groups (P<.05). Probing depth, bleeding index, and plaque index showed no intergroup differences at 6 months (P>.05). Conclusions: The lithium disilicate crowns of all groups showed clinically acceptable fit. No significant differences were found among the groups in terms of periodontal conditions after 6 months.