## 2 Materials and Method
### Surgical Procedures  
The same surgeon (T.R. ), with over 20 years of experience, performed alveolar augmentation and implant procedures. For all patients, systemic antibiotics were given prophylactic preoperatively and at 4 days postoperatively. The procedures of dental implants insertion for test group and control were as follows:  
* Dental implants placement simultaneously with alveolar augmentation by SGBR technique (xenograft, or a mixture with autogenous bone; porcine collagen membrane) (test group);
* Standard dental implants placement (control group). The surgical protocol of S-GBR technique and immediate implant placement is described in Table 3. \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Test Group** & **Control Group** & **Total** \\  & **(S-GBR Sites)** & **(Non-Grafted Sites)** & **Total** \\ \hline N of subjects (Ns) & 10 & 10 & 40 \\ N of sites (Ni) & 30 & 32 & 124 \\ Mean age (range) & (62.30 \(\pm\) 16.059) & (56.60 \(\pm\) 14.159) & (59.45 \(\pm\) 15.220) \\ Gender & & & \\ Men, Ns (Ni) & 4 (12) & 6 (18) & 10 (30) \\ Women, Ns (Ni) & 6 (18) & 4 (14) & 10 (32) \\ \hline \hline \end{tabular}  
* N, number; Ns, number of subjects; Ni, number of sites (implants).  
\end{table} 
Table 1: Characteristics of test and control group. \begin{table}
\begin{tabular}{c c} \hline \hline
**Component** & **Description** \\ \hline Population (P) & Mandibular edentulous patients requiring bone grafting and dental implants \\ \hline Intervention (I) & Augmentation of alveolar bone by S-GBR technique. \\  & Immediate implant placement in grafted sites \\ \hline Comparison (C) & Implant placement in non-grafted sites \\ \hline \hline \multirow{3}{*}{Outcomes (O)} & Primary outcomes: implants success; implants survival \\  & Secondary outcomes: clinical parameters of soft tissues: mPI, mGI, probing depth (mm), \\ \cline{1-1}  & keratinized mucosa (mm), occurrence of peri-mucositis/peri-implantitis (\%); marginal-bone-level \\ \cline{1-1}  & (MBL) (mm); \\ \hline \hline \end{tabular}
\end{table} 
Table 2: PICO study design. Prosthetic loading was carried out after 14-16 weeks following implants placement in the mandible. Each patient was included in a maintenance program consisting of oral hygiene and recall visit every 6 months. Clinical and CBCT aspects of patient from the test group, describing the stages of S-GBR technique and implant-prosthetic stage, are presented in Figures 1-11. CBCT exam allows the evaluation of the horizontal alveolar bone defect and the position of the mandibular alveolar nerf (Figure 1A,B). Figure 1C,D show cross-sectional CBCT aspects of the implant sites. Figure 2 shows the narrowed mandibular alveolar bone with horizontal resorption. Figure 3 shows the exposed buccal surface of the alveolar ridge with severe horizontal resorption, after flap opening. The inserted implants (4.5 mm diameter, 11.5 mm length) and osteosynthesis screws (45\({}^{\circ}\) from the occlusal plan) are shown in Figure 4A. The placement of graft (autologous bone and xenograft) and collagen membrane is shown in Figure 4B. Figure 5A shows tension-free sutures, due to periosteal incisions alveolar ridge. Figure 5B shows clinical aspect at 7 months after surgery, with gingival tissue