## 2 Materials and Methods
The phases described are represented in Figure 1. The test was conducted two consecutive times, with the purpose of evaluating the differences in terms of planning execution time, miniscrew insertion and surgical guide realization. In the digital planning tests, 3 groups of variables were evaluated: miniscrew insertion, the surgical guide design and planning execution time. 1. The miniscrew insertion was evaluated through four variables: safe-zone miniscrew placement, bicorticalism achieved, proximity to the incisive foramen and proximity to the incisive root. 1.1 _Safe-zone miniscrew placement_ was evaluated as positive if both the screws were placed in the 3 rd rugae area [13]. 1.2 _Bicorticalism_ achieved was evaluated as positive if both the screws reached the opposing cortex of the palate [26; 27]. Figure 1: (**a**) On the left, segmented maxillae from the CBCT and, on the right, matching of CBCT and STL file; (**b**) implant insertion in 3D view and cross-sectional view; (**c**) perimeter of the surgical guide and implants rings; and (**d**) surgical guide exported and ready to be 3D-printed. 1.3 Proximity to the incisive foramen was evaluated as positive if at least one of the two miniscrews was placed in contact with the incisive foramen [28]. 1.4 Proximity to the incisive root was assessed as positive if at least one of the minis-crews was placed in contact with the incisive root [28]. 2. Surgical guide design was evaluated thorough three variables: posterior extension, vertical extension and position of the two rings (the empty circular hole that drove the insertion process itself). 2.1 Posterior extension was considered correct when the surgical guides extended up to the first permanent molar and not distally [29]. 2.2 Vertical extension was considered correct if the surgical guide was extended halfway up the crown to achieve retention, by taking advantage of some undercut, and stability of the guide, by wrapping the occlusal face of the teeth [29,30]. 2.3 The positioning of the rings was evaluated through two variables: the overlapping of the rings between them, considering the positioning of the rings separately as correct and the overlapping of the rings with the image corresponding to the palatal mucosa, considering the position of the ring as correct if there was no merging of the rings with the mucosa. 3. Planning execution time was considered as the time in minutes from the opening of the software to the completion of the virtual design of the surgical guide. The _post-test survey_ was performed to evaluate post-operative knowledge and potential difficulties detected during the tests. The survey was composed of 2 sections (5 questions in total) of which the first section concerned a self-evaluation of post-operative knowledge and, the second, the difficulties encountered. All the data from the study were analyzed using IBM SPSS Statistics 25 (IBM, Chicago, IL, USA). Qualitative variables were written as counts or percentages and were tested using [PERSON]'s Exact tests. Quantitative variables were tested for normal distribution using the Shapiro-Wilk Test and were written as averages with standard deviations. The Kruskal-Wallis and Mann-Whitney U-tests were performed to determine the effects of independent variables and interactions between groups. A _p_-value of <0.05 was considered statistically significant.