Effect of splinting scan bodies on trueness of complete-arch implant impression using different intraoral scanners: an in vitro study

Aim: To evaluate the trueness of seven different intraoral scanners (IOSs) in making a complete­arch digital scan with and without splinting the scan bodies. Materials and methods: A polyurethane cast of an edentu­ lous mandible with four dental implant analogs was pre­ pared. A reference scan was made using a laboratory scan­ ner. The reference model was scanned with each of the seven investigated IOSs (control groups, n = 10 per scanner), and scanned again after splinting the scan bodies (study groups, n = 10 per scanner). Each scan was exported as a standard tessellation language (STL) file and transferred to a compre­ hensive metrology software program (Geomagic Control X). In order to measure the trueness, four points (A, B, C, and D) were determined on the scan bodies, and the distance between point A and the other points (DAB, DAC, and DAD) was measured. The measurements were tested for normality using the Kolmogorov­Smirnov test and probability plots. Trueness was compared using three­way analysis of variance (ANOVA), and pairwise comparisons were performed using the post hoc Tukey and paired sample t tests. Statistical analyses were two­sided, and the significance level was set at 5%. Results: Splinting the scan bodies improved the trueness values of the digital scans, while increasing the interimplant distance decreased them. A significant association was found between the trueness values and all three tested vari­ ables, including splinting the scan bodies, type of IOS, and interimplant distance (P < 0.001). Conclusion: Based on the present findings, splinting the scan bodies can improve the trueness of complete­arch digi­ tal implant scans due to the improvement in morphologic landmarks by the stitching process, regardless of the type of IOS or the interimplant distance. (Int J Comput Dent 2023;26(1): 19–28; doi: 10.3290/j.ijcd.b2599297)