## 4 Discussion  
This study compared clinical and radiographic parameters of the implant-supported fixed restorations, following immediate implants placement in sites grafted by the S-GBR technique. A condition of the implants success rate when placed in grafted sites is the absence of post-operatorly early complications due to exposure or improper stabilization of bone graft as well as to post-operatory infection. In our study, post-grafting complications, that could \begin{table}
\begin{tabular}{c c c c} \hline  & **S-GBR Group** & **Control** & \(p\)**-Value** \\ \hline Mean Plaque Index (mPI) (mm) & 0.97 \(\pm\) 0.882 (SD) & 0.66 \(\pm\) 0.695 (SD) & 0.046 * \\ Keratinized mucosa (KM) & 4.13 \(\pm\) 1.033 (SD) & 3.34 \(\pm\) 0.821 (SD) & 0.000 ** \\ Probing Depth (PD) (mm) & 3.50 \(\pm\) 1.372 (SD) & 2.56 \(\pm\) 1.332 (SD) & 0.000 ** \\ Mean mGI & 0.90 \(\pm\) 1.020 (SD) & 0.56 \(\pm\) 0.794 (SD) & 0.061 \\ mGI (scores) & & & \\ Score 0 & 43.3\% & 56.3\% & \\ Score 1 & 36.7\% & 37.5\% & 0.075 \\ Score 2 & 6.7\% & 0.0\% & \\ Score 3 & 13.3\% & 6.3\% & \\ MBL (mm) & 2.20 \(\pm\) 1.867 (SD) & 1.09 \(\pm\) 1.678 (SD) & 0.000 ** \\ \hline \end{tabular}  
* Statistically significant, \(p\) < 0.05; ** Statistically highly significant, \(p\) < 0.01.  
\end{table} 
Table 6: Clinical parameters and radiographic results at 24-months follow-up. \begin{table}
\begin{tabular}{c c c c} \hline  & **S-GBR Group** & **Control** & \(p\)**-Value** \\ \hline Success rate & 76.7\% & 90.6\% & 0.001 ** \\ \hline Survival rate & 86.7\% & 93.8\% & 0.182 \\ \hline \end{tabular}  
* Statistically highly significant, \(p\) < 0.01.  
\end{table} 
Table 7: Success rate and survival rate at 24-months follow-up. interfere with implants osseointegration processes, were absent. The absence of the risk factors (due to the selection criteria of patients) could contribute significantly in maximizing the rate of the grafting procedures success [16]. However, [PERSON] et al. found that the implant survival rate is not influenced by alveolar bone augmentation, despite higher complications rate for implants inserted in sites with vertical and horizontal resorption [17]. The S-GBR technique was performed using mixed grafts (autologous bone and bovine bone). Based on reviewed studies, with a follow-up of minimum 3-5 years, [PERSON] et al. recommend the replacement of allografts and xenografts with autologous bone in the implant sites with medium and severe bone resorption [18]. Xenografts can delay bone formation in comparison to the naturally healed sites, but also preserve the alveolar ridge and stimulate bone formation as to enable placement of implants with high success rate in mandibular implant-prosthetic restorations [19]. Our study investigated the success rate and survival rate of immediate implants placed in alveolar bone reconstructed by S-GBR technique. Immediate implant placement simultaneously with alveolar bone grafting had been well investigated in some systematic review. One study reported, at 20-months follow-up, the absence of statistically significant differences regarding various clinical parameters of the peri-implant soft tissue and peri-implant marginal bone loss, between the immediate implants and delayed implants [20]. In our study we found higher probing depth (\(p\) = 0.000), mGI index (\(p\) = 0.061), and average bone loss (\(p\) = 0.000) for immediate implants placed in grafted sites, when compared with naturally healed sites at 24-month follow-up. However, implant placement simultaneous with horizontal ridge augmentation is recommended when possible as implant survival rates are similar to subsequent implant placement [21]. We found after 24-months follow-up an implant success rate of 76.7% in S-GBR group, while the survival rate was 86.7%. The statistical analysis revealed the lack of significant statistical differences regarding the survival rate, but statistically significant differences for success rate when comparing S-GBR sites and non-grafted sites.