## 3 Results
### Histologic Evaluation  
A semiquantitative evaluation of inflammatory cell infiltration was performed based on the frequency of large phagocytic cells, distinct from normal bone marrow cells, around the implant and cells infiltrating the defect area (Table 1).  
At Week 4, in the FEMTO group, three of six animals showed a moderate severity of inflammatory cell infiltration; in the SLA group, inflammatory cell infiltration was of mild severity or lower in five of six animals. At Week 6, there were no significant differences between the FEMTO and SLA groups, and a mild severity of inflammatory cell infiltration was confirmed in both groups.  
Bone-implant contact (BIC, %) was evaluated to compare the contact pattern between the implant and bone (Figure 8). The ratio of the contact length of new bone to the total length of the eight screw threads per sample was measured, and cases where measurement was not possible--because the screw threads did not appear on the slide--were excluded (Figure 9a).  
Figure 5: ISQ values: (**a**) 4-week group; (**b**) 6-week group. Data shown are mean \(\pm\) standard deviation, two-way analysis of variance. FEMTO, femtosecond laser; ISQ, implant stability quotient; SLA, sandblasted, large-grit, acid-etched; W, week.  
Figure 6: Micro-CT quantitative analysis. BV, bone volume; TV, tissue volume; FEMTO, femtosecond laser; SLA, sandblasted, large-grit, acid-etched; W, week.  
At Week 4, BIC was 49.25 \(\pm\) 21.97% in the FEMTO group, compared with 32.78 \(\pm\) 9.15% in the SLA group (no significant difference between groups). At Week 6, BIC was 48.70 \(\pm\) 11.51% in the FEMTO group, compared with 37.78 \(\pm\) 19.39% in the SLA group (no significant difference between groups).  
At Week 4, the new bone area was similar in the FEMTO group (41.83 \(\pm\) 20.71%) and SLA group (40.75 \(\pm\) 20.73%); corresponding values at Week 6 were 40.95 \(\pm\) 6.53% in the FEMTO group and 35.15 \(\pm\) 25.3% in the SLA group (no significant difference between groups; Figure 9b).  
Figure 7: Micro-CT data for 12 implants. 1R-Prox, 2R-Prox, 3R-Prox, 1L-Dist, 2L-Dist, 3L-Dist, 4R-Prox, 5R-Prox, 6R-Prox, 4L-Dist, 5L-Dist, and 6L-Dist are in the FEMTO group; whereas 1L-Prox, 2L-Prox, 3L-Prox, 1R-Dist, 2R-Dist, 3R-Dist, 4L-Prox, 5L-Prox, 6L-Prox, 4R-Dist, 5R-Dist, and 6R-Dist are in the SLA group. dist, distal; FEMTO, femtosecond laser; L, left; prox, proximal; R, right; SLA, SLA, sandblasted, large-grit, acid-etched; W, week.  
\begin{table}
\begin{tabular}{c c c c c} \hline
**Week** & \multicolumn{2}{c}{**4W**} & \multicolumn{2}{c}{**6W**} \\ \hline
**Group** & **SLA** & **FEMTO** & **SLA** & **FEMTO** \\ \hline No. examined & 6 & 6 & 6 & 6 \\ \hline Inflammatory cell infiltration & 5 (83.3) & 6 (100) & 3 (50.0) & 4 (66.7) \\ \hline \multirow{4}{*}{Severity} & Minimal & 1 & 2 & 2 \\ \cline{2-5}  & Mild & 4 & 1 & 0 & 1 \\ \cline{2-5}  & Moderate & 0 & 3 & 1 & 1 \\ \cline{2-5}  & Severe & 0 & 0 & 0 & 0 \\ \hline Group histological scores & \multirow{2}{*}{1.50 \(\pm\) 0.84} & \multirow{2}{*}{2.17 \(\pm\) 0.98} & \multirow{2}{*}{0.83 \(\pm\) 1.16} & \multirow{2}{*}{1.17 \(\pm\) 1.17} \\ (Mean \(\pm\) SD) & & & & \\ \hline \end{tabular}
\end{table}
Table 1: Histologic evaluation of the degree of inflammatory cell infiltration after surgery. FEMTO, femtosecond laser; SD, standard deviation; SLA, SLA, sandblasted, large-grit, acid-etched; W, week.  
Figure 8: Microscopic images of tissue biopsies after Villanueva staining (each panel shows 500 \(\upmu\)m).