# Influence of the Angle of Periodontal Intrabony Defects on Blood Clots: A Confocal Microscopy Study
## 3 Results  
All samples exhibited signs of retraction, which means the formation of a concavity in the most coronal portion of the clot with separation of the serum component. According to  
Figure 2: Clot analyzed by laser confocal microscopy and measures detected for each sample.  
an initial visual examination under a confocal microscope, lower retraction was observed in the samples treated with EDTA. Analyzing Table 1, the non-treated group (NT) showed that the height of the concavity formed by the clot (H-concavity) remained almost unchanged with varying defect angles. Another important finding from Table 1 is that the largest coronal area formed by clot retraction (S-retraction) exhibited an increase in the mean value with an increase in the defect angle; it transitioned from 1.12 mm\({}^{2}\) in the 25\({}^{\circ}\) angle, to 2.57 mm\({}^{2}\) in the 37\({}^{\circ}\) angle, reaching 5.40 mm\({}^{2}\) in the 50\({}^{\circ}\) angle, confirming that the greater the defect angle, the greater the clot retraction. Our study results show that the area relative to the retracted clot (S-coagulum) increased along with the angle amplitude (Table 1 and Scheme 1), showing a statistically significant relationship between clot retraction and the increase in defect amplitude.  
In the EDTA group, H-concavity data were similar to those of the untreated group. Regarding S-retraction, data showed an increase from the average value of 0.57 mm\({}^{2}\) in the 25-degree samples, 1.10 mm\({}^{2}\) in the 37-degree samples, and finally, 1.21 mm\({}^{2}\) in the 50-degree samples. Similar results were seen for the average values of S-coagulum. The percentage ratio of S-retraction/S-coagulum, however, yielded similar results among the different angles and did not show a progressively increasing trend (Table 1).  
Comparing the results of the two main groups, there was a statistically significant difference. On average (\(p\) < 0.05), the height of the concavity due to clot retraction (H-concavity) was higher in the samples treated with EDTA compared with the NT group (Table 1).  
Another observation arising from the comparison of the two groups was that, in the samples subjected to root conditioning, the surface of the clot retraction (S-retraction) was smaller compared with that of the NT group. The percentage ratio of S-retraction/S  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Angle**} & \multicolumn{2}{c}{**H-Concavity (mm)**} & \multirow{2}{*}{**Values**} & \multirow{2}{*}{**S-Retraction (mm\({}^{2}\))**} & \multirow{2}{*}{**Values**} & \multirow{2}{*}{**S-Clot (mm\({}^{2}\))**} & \multirow{2}{*}{**Values**} & \multirow{2}{*}{**S-Retraction/S-Clot**} & \multirow{2}{*}{**Values**} \\ \cline{2-2} \cline{6-11}  & & & & & & & & & & & **NT** & **EDTA** & **Values** \\ \hline
25\({}^{\circ}\) & 4.85 \(\pm\) 0.32 & 5.13 \(\pm\) 0.15 & 0.14 & 1.12 \(\pm\) 0.06 & 0.57 \(\pm\) 0.09 & 0.012 & 6.33 \(\pm\) 0.29 & 8.14 \(\pm\) 0.64 & 0.012 & 18 \(\pm\) 1 & 7 \(\pm\) 1 & 0.012 \\ \hline
37\({}^{\circ}\) & 4.50 \(\pm\) 0.26 & 5.13 \(\pm\) 0.07 & 0.012 & 2.57 \(\pm\) 0.33 & 1.10 \(\pm\) 0.13 & 0.012 & 8.04 \(\pm\) 1.15 & 9.65 \(\pm\) 0.38 & 0.012 & 32 \(\pm\) 4 & 11 \(\pm\) 1 & 0.012 \\ \hline
50\({}^{\circ}\) & 4.52 \(\pm\) 0.16 & 5.27 \(\pm\) 0.13 & 0.012 & 5.50 \(\pm\) 0.51 & 1.21 \(\pm\) 0.25 & 0.022 & 9.79 \(\pm\) 0.38 & 14.86 \(\pm\) 1.71 & 0.012 & 54 \(\pm\) 6 & 8 \(\pm\) 2 & 0.012 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Average measurements and comparison values related to the NT and EDTA survey group.  
coagulum showed similar values among different angles, specifically an average of 7% in the 25-degree samples, 11% in the 37-degree samples, and 8% in the 50-degree samples. Consequently, these data lacked the linear fitting observed in the corresponding NT group.