# Characterization and Crystallinity of Two Bioactive Sealers: Qualitative and Quantitative Analysis
## 3 Results  
### Raman Spectroscopy  
Figure 1 illustrates the Raman spectra of all the tested sealers before (black) and after immersion for 30 days either in deionized water (blue) or PBS (red) at 1200-800 cm\({}^{-1}\) and presents the parameters of mineral maturity, Raman spectra (area ratio 1030/1110 cm\({}^{-1}\)), and crystallinity index (CI\({}_{\text{Raman}}\) = FWHM of 960 cm\({}^{-1}\)) (Figure 1A-C). The spectra of both bioceramic sealers show that the intensity of the non-apatitic phosphate band at 1110 cm\({}^{-1}\) decreased in water with a further decrease in PBS. In the AH-26 spectra, the value of 1110 cm\({}^{-1}\) was diminished by water and shifted by PBS (Figure 1C). However, the apatite phosphate band at \(\approx\)1030 cm\({}^{-1}\) became very intense in both sealers in PBS (Figure 1A,B). There were changes in its intensity in AH-26 spectra both when immersed in water an in PBS. Furthermore, the band related to hydroxyapatite (\(\approx\)960 cm\({}^{-1}\)) was more intense in Endosequence immersed in PBS (Figure 1D). There was no detection of the 960 cm\({}^{-1}\) band in the AH-26 spectra.  
\begin{table}
\begin{tabular}{c c c c c} \hline
**Measured Parameter** & **Methods** & \begin{tabular}{c} **Formula and Functional** \\ **Group** \\ \end{tabular} & **Band Location (cm\({}^{-1}\))** & **References** \\ \hline \begin{tabular}{c} Crystallinity index \\ Raman (CI\({}_{\text{Raman}}\)) \\ \end{tabular} & Raman & \begin{tabular}{c} FHMW of PO\({}_{4}\)\({}^{3-}\) \\ \end{tabular} & \(\approx\)960 & [PERSON] et al., 2017 [27] \\ \hline \
\begin{tabular}{c} Crystallinity Index \\ (CI\({}_{\text{FTIR}}\)) \\ \end{tabular} & FTIR &
\begin{tabular}{c} Band intensities (at \\ 700–500 cm\({}^{-1}\)) of split \\ doublet \(v_{4}\) phosphate bands \\ \end{tabular} & \(\approx\)600 and 560 cm\({}^{-1}\) & [PERSON], 2010 [30] \\ \hline \end{tabular}
\end{table}
Table 1: _Cont._Figure 1: Raman spectra of all used sealers before (black) or after immersion either in water (blue) or PBS (red), showing bands related to mineral maturity (\(\approx\)1110 and 1030 cm\({}^{-1}\)) (**A**) and apatite phosphate bands (**B**) as well as a crystallinity index (\(\approx\)960 cm\({}^{-1}\)) (**C**). Endosequence immersed in PBS (**D**). Means \(\pm\) standard deviations of mineral maturity (**E**) and Raman crystallinity index (**F**). The symbol (*) refers to the greatest significant mean at \(p<0.001\), the symbol (\(\dagger\)) refers to the lowest significant mean at \(p<0.001\), and the symbol (\(\
eq\)) indicates no significant difference between the sealers of the same symbol at \(p>0.05\).  
Regarding the mineral maturity, there was no significant difference between the three sealers either when dry or when immersed in water (Figure 1E) at \(p\) > 0.05. However, upon immersion in PBS, Endosequence had the greatest significant value (mean = 9.41 \(\pm\) 0.95) and AH-26 had the most significant low value (0.37 \(\pm\) 0.03) at \(p\) < 0.001 (Figure 1E).  
Regarding the crystallinity index (CI\({}_{\rm Raman}\)) in dry conditions, Cerafil had the greatest significant value (24.66 \(\pm\) 0.49) compared to that of Endosequence (22.14 \(\pm\) 0.52) and AH-26 (20.01 \(\pm\) 1.59) at \(p\) < 0.001. It was significantly increased when immersed in water, in both Cerafil and Endosequence (31.91 \(\pm\) 0.4 and 32.72 \(\pm\) 0.42, respectively), and was further increased by PBS (48.4 \(\pm\) 1.55 and 47.57 \(\pm\) 0.53, respectively), with no significant difference between them (\(p\) > 0.05) (Figure 1F). PBS did not affect AH-26.