Assessment of the fit of lithium disilicate crowns at various locations fabricated by three different methods using the triple-scan protocol

Aim: The present study aimed to evaluate the marginal and internal fit of lithium disilicate crowns at various locations. Materials and methods: A typodont maxillary left first molar was prepared for a lithium disilicate crown, scanned, and a master die fabricated. Three groups were created according to fabrication method (n = 10): conventional impression and press method (group C); scanning of definitive cast and milling method (group D); and intraoral scanning and milling method (group I). Assessment was performed using the triple­scan protocol. At the buccopalatal and mesiodistal sections, the absolute marginal discrepancy (AMD), marginal gap (MG), axial internal gap (AI), and line angle internal gap (LI) were meas­ ured. One­way analysis of variance (ANOVA) and post hoc Tukey HSD tests were used for statistical analysis (α = 0.05). Results: AMD values were significantly lower in group C than in groups D and I (P < 0.05). MG values in group C were signifi­ cantly lower than those in the buccal and distal areas in group D and all areas in group I (P < 0.05). AI values in the buccal and palatal areas in group D were significantly lower than those in the mesial and distal areas in group D and all areas in groups C and I (P < 0.05). LI values were significantly lower in group C than in groups D and I (P < 0.05). Conclusion: All three methods were clinically acceptable except for the marginal fit of the intraoral scanning and mill­ ing method, which was on the borderline of a clinically acceptable fit. (Int J Comput Dent 2023;26(1): 37–47; doi: 10.3290/j.ijcd.b3818305)