## 3 Results
### Spectroscopic Analysis  
Carbon and oxygen were the predominant elements on the surface of all samples. These elements result either from test substances or environmental contamination. Titanium was revealed in small proportions as a consequence of environmental contamination by organic compounds or alteration of the surface due to exposure to test agents. The curves of the normalized spectra of Ti2p (Figure 2) are very similar to each other, indicating that the Ti-O bond in TiO\({}_{2}\) (459.3 eV) is dominant in all samples. Other potential bonds formed by titanium cannot be distinguishable on the Ti2p spectra due to their small chemical shifts with respect to the Ti-O bond. Interestingly, titanium could not be detected in the sample treated with 37% OPA acid.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Antiseptics** & _P. Gingivalis_ & _S. Mutans_ \\  & **RF \(\pm\) SD** & **RF \(\pm\) SD** \\ \hline NaOCl 5.25\% liquid & 6.3 \(\pm\) 0.3 \({}^{\#}\) & 7.2 \(\pm\) 0.6 \({}^{*}\) \\ NaOCl 5.25\% gel & 6.5 \(\pm\) 1.0 \({}^{\#}\) & 4.3 \(\pm\) 1.7 \({}^{*}\) \\ CHX 0.2\% liquid & 0.9 \(\pm\) 0.02 \({}^{\#}\) & 0.8 \(\pm\) 0.03 \({}^{*}\) \\ CHX 1\% gel & 6.5 \(\pm\) 1.0 \({}^{\#}\) & 0.9 \(\pm\) 0.1 \({}^{*}\) \\ CA 40\% liquid & 5.3 \(\pm\) 0.1 \({}^{\#}\) & 4.1 \(\pm\) 0.5 \({}^{*}\) \\ OPA 37\% gel & 6.2 \(\pm\) 0.2 \({}^{\#}\) & 7.1 \(\pm\) 0.5 \({}^{*}\) \\ \hline \hline \end{tabular}  
NaOCl, sodium hypochlorite; CHX, chlorhexiidine; CA, citric acid; OPA, orthophosphoric acid; \(\#\), \(p<\) 0.0001 and \({}^{*}\), \(p<\) 0.01 vs. control (NaCl 0.9%).  
\end{table}
Table 1: Antibacterial activity of the antiseptics against _P. gingivalis_ and _S. mutans_ after 2 min of exposure.  
Figure 1: SEM images (magnification \(\times\)10,000) of _S. mutans_ and _P.gingivalis_ biofilms attached on titanium surface after exposure to antiseptic for 2 min. NaCl, sodium hypochlorite; CHX, chlorhexidine; CA, citric acid; OPA, orthophosphoric acid; control, NaCl 0.9%.  
Spectra relative to the peak O1s (Figure 3) show very different characteristics among the samples. Each spectrum can be interpreted as a composition of peaks at the characteristic energies of the different bonds in different proportions from one sample to another. All samples show the peak corresponding to the Ti-O bond, together with the peaks of the C = O, C-O and OH bonds. Sample F, the only one that contained phosphorus, showed a predominance of the peak corresponding to the P-O bond.  
C1s spectra (Figure 4) also differed among the samples. These spectra are the result of the composition of numerous peaks corresponding to the energies of the different bonds indicated in the figure, and present in different proportions. In particular, O = C-O, C-C, O, C-OH, and C-NH bonds were observed. The Ti-C bond was not detected.  
Figure 3: Normalized spectra of O1s of non-contaminated titanium samples after immersion in 1 mL of each antiseptic product for 2 min. (**CC**) Control; (**A**) NaOCl 5.25% liquid; (**B**) NaOCl 5.25% gel; (**C**) CHX 0.2% liquid; (**D**) CHX 1% gel; (**E**) AC 40% gel; (**F**) OPA 37% gel.  
Figure 2: Normalized spectra of Ti2p of non-contaminated titanium samples after immersion in 1 mL of each antiseptic product for 2 min. (**CC**) Control; (**A**) NaOCl 5.25% liquid; (**B**) NaOCl 5.25% gel; (**C**) CHX 0.2% liquid; (**D**) CHX 1% gel; (**E**) AC 40% gel.  
Sodium was detectable in all samples, in small and always different proportions. Even nitrogen was always visible, but at the limit of detectability. The chlorine signal was absent in the CC and F samples, while in the other samples it was not quantifiable. Phosphorus was present only in sample F.