## 2 Materials and Methods  
A total of 30 clinicians, with different levels of clinical and digital experience, were randomly recruited in this cross-sectional study to evaluate the capacity of virtual planning in palatal orthodontic miniscrew insertion. The investigation was reviewed and approved by the regional Ethical Review Board of the Umberto I Polyclinic Hospital, Rome Italy (N.4663) The sample was recruited from January to September 2022 and was composed of three groups: 10 dental students (all attending their sixth year of the dentistry course at Sapienza University of Rome), 10 orthodontics students (orthodontics postgraduate school of Sapienza University of Rome) and 10 orthodontists (orthodontic specialists in Rome). To determine appropriate sample size, pilot experiments were conducted, and this was calculated as 10 per group, in order to have an 80% probability of detecting 20% knowledge difference among groups with a 95% (\(p<0.05\)) level of significance. All participants performed a pre-test survey followed by two consecutive digital planning tests and, finally, a post-test survey. All participants signed an informed consent form for participation in the study, both in the surveys and in the tests; an identification code was used for each participant for privacy reasons. The pre-test and the post-test surveys were made by Google Forms(r) program, creating two surveys with multiple choice questions. (Data available in the Appendices A and B). The pre-test survey was performed by all clinicians to evaluate clinical experience and digital knowledge. This survey was composed of 2 sections (7 questions in total) of which the first section was regarding clinical experience on miniscrew placement and the second section was about digital knowledge in the use of Digital Imaging and Communication in Medicine (DICOM) image evaluation software and, in particular, digital planning of TADs insertion. The evaluation of the clinical experience was based on a self-assessment test of the theoretical and practical knowledge and the clinical experience of the participants in the positioning of palatal miniscrews by means of 4 questions (Appendix A.1-4). A score was assigned to each question and a final scale from 0 to 3 was obtained, indicating the level of clinical knowledge of the participant. Later, the answer was transformed into \"YES clinical experience\" (a score of 2 or 3) or \"NO clinical experience\" (values less than 2) based on the test result. In the same way, previous digital knowledge in the treatment of medical images was evaluated through a self-assessment test (Appendix A.5-7) assigning a value to each question from 0 to 3 and obtaining a final evaluation as \"YES digital knowledge\" (a score of 2 or 3) and \"NO digital knowledge\" (values less than 2). The digital planning test was made using software BlueSkyBio-BlueSkyPlan(r) ver. 4.7.55, surgical guide module. All tests were performed on the same patient's examinations, ensuring comparison criteria between the tests. For all the participants, it was their first time using this software. The patient was selected from the Department's Orthodontic Unit list among those who would have performed miniscrew-assisted distalization. The patient records used were a facial skeletal CBCT (prescribed because this specific patient had to undergo presurgical orthodontic treatment) made with Carestream CS 8200 3D machine (volume of 150 \(\times\) 100 \(\times\) 80 mm), and an oral scan obtained by scanning a cast made from an alginate impression using Carestream CS 3500 oral scanner. Before the performance, all the clinicians were instructed to view an introductory video guide supplied by the software's team. A folder containing a CBCT and a Standard Triangle Language (STL) impression file of the patient was given to each clinician, with the instructions to match the two files and place two miniscrews in the anterior part of the palate and then generate a surgical guide to reproduce the planned insertion in the patient's oral cavity.