## 3 Results  
A total of 56 subjects took part in this study. This included 26 women and 30 men. All adults were at least 18 years of age and ranged up to an age of 72 years. The total number of implants placed were 97. The number of patients in whom NCLMs were used was 52, and the number of patients with CLMs was 4. There were 32 patients who underwent bone grafting and implantation in the maxilla, 13 patients in the mandible, and 11 patients in the maxilla and mandible. In addition, 21 patients were treated in the anterior region, and 35 patients were treated in the posterior region. There were 23 patients with horizontally-augmenting bone grafts, 21 patients with vertically-augmenting grafts, and 12 patients with bi-directional grafts. There were 43 patients with external-type implants and 13 with internal-type implants. A total of 28 patients had a one-stage implantation, and 28 underwent a two-stage implantation. These results are summarized in Table 1, which also shows the number of exposed implant threads observed in each factor.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \multicolumn{2}{c}{**Factors**} & \multicolumn{2}{c}{**Number of Patients**} & **Number of Exposed Threads** & **F Value** & **\(p\) (<0.05)** \\ \hline \multirow{2}{*}{Gender} & M & 30 & 1.212121 & \multirow{2}{*}{0.56} & \multirow{2}{*}{0.457} \\  & F & 26 & 1.423077 & & \\ \hline \multirow{4}{*}{Age} & 20s & 7 & 0.714286 & \multirow{4}{*}{0.026} \\  & 30s & 4 & 2.00000 & & \\  & 40s & 14 & 1.500000 & & \\  & 50s & 17 & 1.400000 & & \\  & Above 60s & 14 & 1.250000 & & \\ \hline \multirow{4}{*}{Mx. or Mn.} & Mx. & 32 & 1.171429 & \multirow{4}{*}{0.020 (\(\tau\))} \\  & Mn. & 13 & 1.00000 & & \\  & both & 11 & 2.090909 & & \\ \hline \multirow{4}{*}{Extracted teeth position (dentition)} & Ant. & 21 & 1.333333 & \multirow{4}{*}{0.022} & \multirow{4}{*}{0.882} \\  & Post. & 35 & 1.289474 & & \\ \hline \multirow{4}{*}{Bone graft type} & Horizontal & 23 & 1.192308 & \multirow{4}{*}{1.903} & \multirow{4}{*}{0.159} \\  & Vertical & 21 & 1.142857 & & \\  & Combined & 12 & 1.833333 & & \\ \hline \multirow{4}{*}{Implantation stage} & 1 stage & 28 & 1.250000 & \multirow{4}{*}{0.139} & \multirow{4}{*}{0.711} \\  & 2 stage & 28 & 1.354839 & & \\ \hline \multirow{4}{*}{Implant type} & External & 43 & 1.418605 & \multirow{4}{*}{2.156} & \multirow{4}{*}{0.148} \\  & Internal & 13 & 0.923077 & & \\ \hline \multirow{4}{*}{Membrane type} & NCLM & 52 & 1.269231 & \multirow{4}{*}{0.736} & \multirow{4}{*}{0.395} \\  & CLM & 4 & 1.750000 & & \\ \hline \end{tabular}
\end{table}
Table 1: The numbers of exposed implant threads in each factor. (Abbreviations; Maxilla: Mx., Mandible: Mn, Non-cross-linking membrane: NCLM, Cross-linking membrane: CLM, \({}^{*}p<0.05\))  
Figure 2: Orthopantomographic images. (**A**) On the day of the mandibular block bone graft; (**B**) Immediately after installation of implants; (**C**) One year after installation of the implants. Analysis between (**B**,**C**) orthopantomographic X-ray (OPTG) images were performed to check the number of exposed threads.  
There was no significant difference between the groups (\(p>0.05\)). However, there was a statistically significant difference (\(p=0.02\)) between the groups when a bone graft was applied to both the maxilla and the mandible. The average number of thread exposures was less than 1.5. However, the number of thread exposures was more than two in the 30-years age group and in the case of multiple implantations in both jaws. Figure 3 visualizes the table.