## 3 Results
Table 5 shows the area of remnants measured in the coronal, middle, and apical thirds after retreatment with RB40 and RB50. For the coronal third, the remnant area for SC was 0 mm\({}^{2}\) after RB40 and remained 0 mm\({}^{2}\) after RB50. For the GF group, the remnant area was 0.01 \(\pm\) 0.02 mm\({}^{2}\) after RB40 and 0 after RB50. In the middle third, the remnant area for the SC was 0.23 \(\pm\) 0.43 mm\({}^{2}\) after RB40 and 0.17 \(\pm\) 0.37 mm\({}^{2}\) after RB50, representing a reduction of 26.09%. For the GF group, it was 0.33 \(\pm\) 0.55 mm\({}^{2}\) after RB40 and 0.20 \(\pm\) 0.35 mm\({}^{2}\) after RB50, representing a reduction of 31.3%. In the apical third, the remnant area for the SC group was 0.25 \(\pm\) 0.47 mm\({}^{2}\) after RB40 and 0.22 \(\pm\) 0.44 mm\({}^{2}\) after RB50, representing a reduction of 8.33%. For the GF group, it was 0.25 \(\pm\) 0.28 mm\({}^{2}\) after RB40 and 0.11 \(\pm\) 0.12 mm\({}^{2}\) after RB50, representing a reduction of 56%. Table 6a,b shows the comparison of the percentage of remnants after retreatment with RB40 and RB50 (expressed as mean \(\pm\) SD) between the SC and GF techniques. For the SC group, the percentage of remnant area was 6.2 \(\pm\) 11.9% after RB40 and 5.10 \(\pm\) 10.7% after RB50, representing an overall reduction of 17.74%. The percentage of remnant volume was 3.1 \(\pm\) 5.2% after RB40 and 2.4 \(\pm\) 4.8% after RB50, representing an overall reduction of 22.58%. For the GF group, the percentage of remnant area was 7.3 \(\pm\) 9.3% after RB40 and 5.0 \(\pm\) 8.0% after RB50, representing a reduction of 31.51%. The percentage of remnant volume was 3.0 \(\pm\) 3.3% after RB40 and 2.0 \(\pm\) 2.5% after RB50, representing a reduction of 33.3%. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \multirow{2}{*}{**Reciproc Blue**} & \multicolumn{3}{c}{**Single Cone (\(n\) = 11)**} & \multicolumn{3}{c}{**Guttafusion (\(n\) = 10)**} & \multicolumn{3}{c}{**Difference**} \\ \cline{2-10}  & **Mean** & **SD** & **95\% CI** & **Mean** & **SD** & **95\% CI** & **Mean** & \(p\)**-Value** & **95\% CI** \\ \hline RB40 & 0.63 & 1.22 & \(-\)0.19, 1.45 & 0.55 & 0.91 & \(-\)0.10, 1.21 & 0.08 & 0.868 & \(-\)0.91, 1.07 \\ RB50 & 0.51 & 1.16 & \(-\)0.27, 1.29 & 0.36 & 0.59 & \(-\)0.06, 0.78 & 0.15 & 0.715 & \(-\)0.70, 1.01 \\ \hline \end{tabular}
\end{table} 
Table 4: Remnants volume (mm\({}^{3}\)) obtained through digital reconstruction of CBCT images after retreatment with Reciproc Blue (RB) 40 and 50, by obturation technique. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \multirow{2}{*}{**Reciproc Blue**} & \multicolumn{3}{c}{**Single Cone (\(n\) = 11)**} & \multicolumn{3}{c}{**Guttafusion (\(n\) = 10)**} & \multicolumn{3}{c}{**Difference**} \\ \cline{2-10}  & **Mean** & **SD** & **95\% CI** & **Mean** & **SD** & **95\% CI** & **Mean** & \(p\)**-Value** & **95\% CI** \\ \hline RB40 & 0.47 & 0.90 & \(-\)0.13, 1.08 & 0.59 & 0.77 & 0.04, 1.15 & \(-\)0.12 & 0.752 & \(-\)0.89, 0.65 \\ RB50 & 0.39 & 0.80 & \(-\)0.15, 0.93 & 0.18 * & 0.33 & \(-\)0.07, 0.44 & 0.20 & 0.485 & \(-\)0.40, 0.81 \\ \hline \end{tabular}
\end{table} 
Table 3: Residual filling material area (mm\({}^{2}\)) calculated on periodical radiographs after retreatment with Reciproc Blue (RB) 40 and 50, by obturation technique.