## 3 Results  
A total of 470 CBCT were collected from patients with monoedentulism of a maxillary incisor who were candidates for implant therapy. Only 95 of 470 repeated the CBCT examination for control or occasionally (for the study of other pathological conditions). Of the 95 patients selected, it was possible to perform post-extractive immediate implant insertion in 37 (group 1) and delayed implant insertion in 58 (group 2) due to unfavourable anatomical conditions that required the application of alveolar preservation techniques. All procedures in group 1 and group 2 were performed without the preparation of an access flap.  
In group 1, the mean deviation of apico-coronal placement and implant axis (Figure 1) was 1.04\({}^{\circ}\)\(\pm\) 0.56\({}^{\circ}\) in sagittal projection, the mean mesiodistal deviation of the implant with adjacent teeth was 0.14 mm \(\pm\) 0.07 mm at the implant head (Figure 2) and 0.56 mm \(\pm\) 0.24 mm at the apex in axial projection (Figure 3).  
\begin{table}
\begin{tabular}{l} \hline \hline
**Inclusion Criteria** \\ \hline \(\bullet\) & placement of single implants in the last 5 years in the maxillary incisor area \\ \(\bullet\) & radiographic data collection exclusively by cone beam CT \\ \(\bullet\) & selection of patients who had preoperative and postoperative CT scans \\ \(\bullet\) & computer guided implant placement with the use of 3D-printed templates \\ \(\bullet\) & immediate and delayed postextractive implants \\ \(\bullet\) & implant length: 10 \(\pm\) 1 mm \\ \hline \hline \end{tabular}
\end{table}
Table 1: Inclusion criteria.  
\begin{table}
\begin{tabular}{l} \hline \hline
**Exclusion Criteria** \\ \hline \(\bullet\) & patients who did not have natural incisors adjacent to the dendulous space \\ \(\bullet\) & smoking patients \\ \(\bullet\) & patients with untreated hard/soft tissue dehiscences \\ \hline \hline \end{tabular}
\end{table}
Table 2: Exclusion criteria.  
In group 2, the mean deviation of apico-coronal placement and implant axis was \(1.18^{\circ}\pm 0.54^{\circ}\) in sagittal projection, the mean mesiodistal deviation of the implant with adjacent teeth was \(0.23\) mm \(\pm\) 0.15 mm at the implant head and \(0.53\) mm \(\pm\) 0.25 mm at the apex in axial projection.  
The data distribution of the difference between design and implant placement in vivo is not Gaussian, so [PERSON]'s nonparametric test for paired data was used.  
In both groups, the difference was statistically significant for the parameters \"implant axis\" (group 1--\(p\) = 0.036; group 2--\(p\) = 0.022) and \"mesiodistal deviation at implant apex\" (group 1--\(p\) = 0.002; group 2--\(p\) = 0.0001), while it was not statistically significant for the parameter \"mesiodistal deviation at implant head\" (group 1--\(p\) = 0.051; group 2--\(p\) = 0.122).  
To compare the differences between group 1 and group 2, a Mann-Whitney U-test for unpaired data was performed. Statistically significant differences between groups were found only for the parameter \"mesiodistal deviation at implant head\" (\(p\) = 0.007), whereas no significant differences were found for the \"implant axis\" (\(p\) = 0.172) and \"implant apex\" (\(p\) = 0.611).  
Figure 1: Comparison of implant axis on CBCT scans performed before and after implant surgery to verify congruence of implant placement (in orange). In blue, virtual wax-up of the future fixed crown. (**a**) Implant position in preoperative digital planning; (**b**) Implant position after computer-guided surgical insertion.  
Figure 2: Comparison of mesiodistal deviation with adjacent teeth on CBCT scans performed before implant surgery to verify the congruence of implant placement. (**a**) Implant position in preoperative digital planning in coronal projection; (**b**) mesiodistal deviation of the implant with adjacent teeth at implant axis in axial projection; (**c**) mesiodistal deviation of the implant with adjacent teeth at implant head in axial projection.