## 4 Discussion
(5.36 \(\pm\) 4.53\({}^{\circ}\) and 3.60 \(\pm\) 2.84\({}^{\circ}\)) [20]. The mesial-distal deviation results at platform and apex levels in the present study (0.59 \(\pm\) 1.49 mm and 1.49 \(\pm\) 0.59 mm, respectively; see Table S2) were considerably smaller than those reported by [PERSON] et al. [21] for the corresponding variables in the FHgroup (1.30 \(\pm\) 0.83 mm and 5.38 \(\pm\) 1.78 mm, respectively). The same trend was also seen in the buccal-palatal deviation results from the present study at platform and apex levels (0.36 \(\pm\) 0.28 mm and 0.77 \(\pm\) 0.59 mm, respectively; see Table S2), compared to the results reported by [PERSON] et al. (1.06 \(\pm\) 0.91 mm and 4.36 \(\pm\) 1.84 mm, respectively). These differences could be explained by the lack of real-life clinical elements such as a patient's tongue or limited occlusal space in the present study's experimental setup. While implants placed fully guided may have deviated the least from their planned positions, the maximum global deviation was still almost 2 mm; therefore, a safety margin of 2 mm around important anatomical structures is still recommended. An unexpected result from the present study was the lack of a significant difference in global platform and apical deviation between implants placed freehand and those placed using a pilot guide. This result is contrary to a recent study by [PERSON] et al., in which a significant difference in global platform and apical deviation was found between immediate implants placed using partially guided surgical guides and implants placed freehand. However, the osteectomies in the partially guided group were fully prepared through the surgical guide, after which the guide was removed for implant placement [22]. The non-significant result from the present study could therefore be explained by the lack of guide support during osteotomy preparation after the pilot drill. The benefit of guided surgery for healed sites is well established, with multiple RCTs reporting significant differences in accuracy between implants placed with a guide (full, partial, or pilot) and implants placed freehand [19; 27; 28; 29]. On the other hand, there is a lack of RCT studies comparing full, partial, and pilot-guided approaches versus freehand in post-extraction sockets. The global deviation results from the present study would suggest that pilot guides have limited value for placing implants in post-extraction sockets compared to a freehand approach. However, immediate implant placement is a technically challenging procedure for any surgeon. When considering the angular deviation, there is a significant difference between implants placed using a pilot guide and implants placed freehand (see Supplementary Table S2). The 'Treatment Evaluation' tool in CoDiagnostix(r) has been used by multiple authors to calculate postoperative implant deviation [20; 28; 30] and was a logical choice in the present study as it is fully integrated within the software package. All postoperative scan files were added to the original implant plan using the standard tool for importing intra-oral scans, thereby preserving the original coordinate system and clinical directions. This contrasts with other evaluation tools in similar accuracy studies [19; 21; 22; 27], where the process of matching of the pre- and postoperative scan or CBCT files and calculating the deviation was more manual and the original coordinate system and clinical directions from the implant plan were lost. Finally, the results of the present study should be interpreted with caution. Important real-life clinical elements (such as patient movement or limited occlusal distance) could further influence the deviation in implants placed in post-extraction sockets, which was not possible to reflect in the present study. The mechanical properties of the resin in the surgical teaching models were also not entirely representative of human bone, which could be seen as a limitation of the present study.