Predictability of intraoral scanner error for full-arch implant-supported rehabilitation

Abstract

Objectives The present study aimed to analyze the behaviors of three intraoral scanners (IOSs): evaluating the interdistance and axial inclination discrepancies in full-arch scans, predictable errors were searched. Materials and methods Six edentulous sample models with variable numbers of dental implants were used; reference data were obtained with a coordinate-measuring machine (CMM). Each IOS (i.e., Primescan, CS3600, and Trios3) performed 10 scans per model (180 total scans). The origin of each scan body was used as a reference point to measure interdistance lengths and axial inclinations. Precision and trueness of interdistance measurements and axial inclinations were evaluated to address error predictability. Bland–Altman analysis, followed by linear regression analysis and Friedman’s test (plus Dunn’s post hoc correction), was performed to evaluate the precision and trueness. Results Regarding interdistance, Primescan showed the best precision (mean ± SD: 0.047 ± 0.020 mm), while Trios3 underestimated the reference value more than the others (p < 0.001) and had the worst performance (mean ± SD: −0.079 ± 0.048 mm). Concerning the inclination angle, Primescan and Trios3 tended to overestimate angle values, while CS3600 underestimated them. Primescan had fewer inclination angle outliers, but it tended to add 0.4–0.6° to the measurements. Conclusions IOSs showed predictable errors: they tended to overestimate or underestimate linear measurements and axial inclinations of scan bodies, one added 0.4–0.6° to the angle inclination values. In particular, they showed heteroscedasticity, a behavior probably related to the software or the device itself. Clinical significance IOSs showed predictable errors that could affect clinical success. When performing a scan or choosing a scanner, clinicians should clearly know their behaviors.

Conventional and Digital Impressions for Fabrication of Complete Implant-Supported Bars: A Comparative In Vitro Study

“…It seems that the open tray with splinted transfers associated with high-precision elastomers such as VPS or polyether is the most accurate technique to obtain working models for implant-supported prostheses [10], and the present study used this method for the conventional impression group. Studies and reviews have attempted to elucidate the feasibility of using intraoral digital impressions in full-arch implant-supported prostheses cases, with general agreement on the challenges associated with the technique [12][13][14]17,[24][25][26][27][28][29][30][31][32][36][37][38]. The large area to be scanned increases the risk of minor deviations accumulating during the formation of three-dimensional (3D) images [29].…”

“…While the digital impression technique for teeth and single implant-supported p theses is well-established, there is still a need for further development and discussio garding intraoral digital impressions in full arches [13,17,18,[28][29][30][31]33,36,37]. There this study aimed to compare, in vitro, digital impressions using an intraoral scanner conventional impressions using elastomers by measuring the vertical misfit in the a ment/prosthesis interface in full-arch implant-supported bars obtained via both meth The null hypothesis is that there are no differences in misfit in the structures designe models obtained using digital and conventional impressions.…”

“…However, in multiple implants [24], especially for full-arch cases [17,[25][26][27][28][29][30][31][32][33][34][35][36][37][38], intraoral digital impressions still lack predictability. Numerous methods have been used to assess the quality or accuracy of intraoral digital impressions for multiple implants.…”

“…Numerous methods have been used to assess the quality or accuracy of intraoral digital impressions for multiple implants. The most common is the use of coordinate-measurement machines and the analysis of 3D coordinate axes obtained through superimposition of STL files generated using a laboratory scanner (control) and intraoral scanner and elastomeric impression tests [12,14,16,[24][25][26][29][30][31][32][33]. They can measure the 3D deviation and, consequently, the trueness and precision between the experimental models and the master model without the need to construct prostheses.…”

“…Moreover, caution is advised when using digital impressions for multiple implants with an angulation exceeding 15 • , as the results may be unreliable [33]. Even in more recent studies, authors have demonstrated that intraoral scanning can exhibit errors that may impact clinical success [31,33]. Despite these limitations, other studies have presented promising outcomes regarding intraoral scanning for implant full-arch rehabilitations.…”