Effect of Scan Body Modifications on the Accuracy of Digital Implant Impressions for Totally Edentulous Patients: An In Vitro Study

Description :

Various studies have been put forward to improve the scan accuracy in such situations. Iturrate et al. suggested adding an auxiliary geometry part simulating a jaw with teeth in order to fill the gaps between the scannable impression copings (Iturrate et al., 2019). Results have shown that the use of an auxiliary geometry piece improved the accuracy of complete-arch digital impressions of the edentulous maxilla in terms of trueness and precision and facilitated the scanning process itself. However, this technique has several disadvantages that make it impractical in clinical practice. First, it requires additional processes where the auxiliary device has to be customized and manufactured. Second, it’s relatively difficult to secure it over the soft tissues in place. Third, double scanning procedures should be made where the digital impression is taken from two scans, making the procedure complicated and lengthy. Motel et al. suggested a new scan strategy where the technique involved two scans (Motel et al., 2019). The first scan was without scan bodies and the second scan was with scan bodies. After that both scans were overlaid and compared with the reference scan. Unfortunately, his study showed that single strategy technique provides more accurate results. Mizumoto et al., evaluated the effects of 4 scanning techniques and 5 intraoral scan bodies (ISBs) on the trueness, precision, and scan time in a completely edentulous arch with 4 implants. (Mizumoto et al., 2020). The different scanning techniques introduced in the study were adding glass fiduciary markers on the edentulous ridge, pressure-indicating paste brushed over the ridge and palate, and floss tied between the scan bodies. The accuracy (trueness and precision) of complete-arch digital implant scans using ISBs was affected by the scan body used. However, the scan techniques with different surface modifications were not found to improve the scan accuracy. Due to the limitations of the studies aforementioned, this research aims to provide a novel approach in increasing the accuracy of implant complete fixed prosthesis cases.