## 4 Discussion  
None of the frameworks realized by full-arch digital impressions showed misfit, either clinically onto the patient or onto the master model. Moreover, the radiograph examinations performed on the randomized framework did not reveal any misfit either. The passive fit can be assessed using two methods: in vivo and in vitro. Clinically, various techniques have been introduced; however, none has gained full acceptance as a thorough test [25]. The Sheffield test, finger pressure, visual inspection, tactile sensations, radiographs, and screw-resistant test are the main in vivo methods described in the literature to assess the implant-framework gap, but every procedure has merits and limitations [21,22,25]. The major studies published in the literature assessed the marginal fit of a single crown on an abutment tooth. [PERSON] et al. [26] investigated the range of values for the marginal and internal fit of a single crown on an abutment tooth. The findings highlighted \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Framework** & **Implant 1** & **Implant 2** & **Implant 3** & **Implant 4** & **Implant 5** & **Implant 6** & **Mean** & **SD** \\  & **(\(\upmu\)m)** & **(\(\upmu\)m)** & **(\(\upmu\)m)** & **(\(\upmu\)m)** & **(\(\upmu\)m)** & **(\(\upmu\)m)** & **(\(\upmu\)m)** & **SD** \\ \hline
1 & 35 & 33 & 44 & 45 & 38 & 33 & 38 & 5 \\
2 & 43 & 39 & 46 & 51 & 44 & 41 & 44 & 4 \\
3 & 35 & 33 & 42 & 45 & 36 & 38 & 38 & 5 \\
4 & 38 & 35 & 36 & 33 & 33 & 35 & 35 & 2 \\
5 & 40 & 39 & 48 & 44 & 38 & 37 & 41 & 4 \\
6 & 28 & 31 & 39 & 41 & 33 & 30 & 34 & 5 \\
7 & 30 & 32 & 39 & 51 & 37 & 33 & 37 & 8 \\
8 & 31 & 31 & 44 & 41 & 29 & 30 & 34 & 6 \\
9 & 32 & 34 & 41 & 40 & 37 & 36 & 37 & 3 \\
10 & 44 & 38 & 40 & 53 & 43 & 45 & 44 & 5 \\
**Mean** & **35** & **34** & **42** & **45** & **37** & **36** & & \\ SD & 5 & 3 & 4 & 6 & 4 & 5 & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: In vitro analysis of the Sheffield test outcomes for the frameworks. Figure 6: Radiograph examinations. the better marginal fit (55.01 \(\pm\) 7 \(\upmu\)m) of the coping realized by using a digital impression than from traditional impressions (75.04 \(\pm\) 13 \(\upmu\)m). However, both the mean values were clinically acceptable. The same results were reported in a recent article where the authors investigated the marginal fit of crowns generated by using digital impressions realized with several intraoral scanners [27]. The authors reported an average marginal gap value of 53.45 \(\pm\) 30.52 \(\upmu\)m. The minimum mean value was recorded by using PlanScan (40.04 \(\pm\) 18.90 \(\upmu\)m); meanwhile, the maximum mean value (67.95 \(\pm\) 30.41 \(\upmu\)m) was recorded by TRIOS 3. The other intraoral scanners yielded the following average marginal gap values: 3D PROGRESS Plus (40.20 \(\pm\) 21.91 \(\upmu\)m), True Definition Scanner (40.82 \(\pm\) 26.19 \(\upmu\)m), CS3500(r) (54.82 \(\pm\) 28.86 \(\upmu\)m) CS3600 (5967 \(\pm\) 28.72 \(\upmu\)m), Omnicam (61.57 \(\pm\) 38.59 \(\upmu\)m), and DWIO (62.49 \(\pm\) 31.54 \(\upmu\)m) [27]. Regarding the passive fit generated by digital full-arch implant impressions, few in vivo studies have been conducted. To the best of the authors' knowledge, there are only three studies [18; 19; 20]. [PERSON] et al. [18] demonstrated that it is possible to manufacture a CAD/CAM cobalt-chromium full-arch framework following a digital impression. After implant placement, 25 patients were rehabilitated with an \"all on four\" technique following the digital or conventional workflow. No misfit emerged through panoramic radiographs after 3-, 6-, and 12-month follow-up examinations. A similar result was reported by [PERSON] et al. [19], who analyzed the success of full-arch maxillary rehabilitation after 24 months. X-ray examinations revealed no clinical misfit among frameworks and implants. The investigation conducted by [PERSON] et al. [20] had a different purpose.