# Salivary Extracellular DNA and DNase Activity in Periodontitis
## 4 Results  
This study included 25 patients with periodontitis and 29 healthy controls. Patient characteristics are shown in Table 1. All patients were characterized using GI and PBI score as well as BOP expressed as a percentage. Individuals in the control group had no BOP and no sign of alveolar bone loss. Significantly higher values were observed in periodontitis patients in comparison to healthy controls according to GI, PBI and BOP (Table 1). No gender differences were observed in further analyses. DNA concentration in whole saliva showed significantly higher values in periodontitis compared to healthy controls (504.6 \(\pm\) 82.32 vs. 237.4 \(\pm\) 26.66 ng/mg; \(p\) < 0.01) (Figure 1). Once the whole saliva was centrifuged, there were no differences observed in concentration of DNA between periodontitis and healthy controls (69.59 \(\pm\) 13.37 vs. 54.22 \(\pm\) 8.06 ng/mg; \(p\) = ns) (Figure 1). Similarly, in double-centrifuged samples, total ecDNA concentrations did not differ between the groups, periodontitis vs. healthy (13.54 \(\pm\) 1.14 vs. 16.14 \(\pm\) 2.54 ng/mg; \(p\) = ns; Figure 1). Determination of nuclear DNA in centrifuged samples showed no differences between groups, periodontitis vs. healthy (6629 \(\pm\) 1727 vs. 5638 \(\pm\) 2151 copy/mg; \(p\) = ns; Figure 2A). However mtDNA was significantly increased in periodontitis in comparison to healthy controls (10,656,989 \(\pm\) 3,419,262 vs. 2,630,658 \(\pm\) 809,983 copy/mg; \(p\) < 0.05; Figure 2B). In double-centrifuged samples, ncDNA concentration was significantly lower in the periodontitis group in comparison to the healthy group (788.8 \(\pm\) 238.8 vs. 4947 \(\pm\) 1508 copy/mg; \(p\) < 0.01) (Figure 2A), although mtDNA concentration was similar in both groups (14,608 \(\pm\) 4809 vs. 11,957 \(\pm\) 3296 copy/mg; \(p\) = ns; Figure 2B). Figure 1: Total DNA in whole saliva, centrifuged saliva (1600\(\times\)_g_) and double-centrifuged saliva (1600\(\times\)_g_ + 16,000\(\times\)_g_). Results are expressed as mean + SEM. Salivary DNA is higher in periodontitis in whole saliva (_p_ < 0.01**). No differences were found in centrifuged and double-centrifuged samples between the healthy and periodontitis group. Figure 2: The effect of periodontitis on **A**: nuclear DNA (ncDNA). No differences were found in centrifuged samples. NcDNA was significantly lower in periodontitis in double-centrifuged samples (_p_ < 0.01**). The effect of periodontitis on **B**: mitochondrial DNA (mtDNA). MtDNA was significantly higher in periodontitis in centrifuged samples. No differences were found in double-centrifuged samples. Results are expressed as mean + SEM. Correlation analysis revealed that there is no linear association between concentration of total DNA, mtDNA, ncDNA and health indexes of periodontitis patients (Table 2). Only significant and positive correlation was observed between PBI and mtDNA in centrifuged samples (r = 0.62; Table 2). No significant differences were found in DNase activity between periodontitis samples and healthy controls either in centrifuged samples (\(0.54\pm 0.06\) vs. \(0.39\pm 0.05\) KU/mg; \(p=\) ns) or in double-centrifuged samples (\(0.51\pm 0.03\) vs. \(0.53\pm 0.03\) KU/mg; \(p=\) ns; Figure 3). No significant correlations were found beside the positive significant correlation between PBI and mtDNA in centrifuged samples (\(p<0.05^{*}\)). \begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Centrifuged** & **Double Centrifuged** \\ \hline PBI DNA & & \\ \hline GI (score) & r = 0.01 & r = \(-\)0.01 \\ \hline PBI (score) & r = 0.24 & r = \(-\)0.08 \\ \hline BOP (\%) & r = \(-\)0.01 & r = \(-\)0.1 \\ \hline Nuclear DNA & & \\ \hline GI (score) & r = 0.16 & r = 0.25 \\ \hline PBI (score) & r = 0.35 & r = 0.2 \\ \hline BOP (\%) & r = 0.03 & r = 0.28 \\ \hline Microfunctional DNA & & \\ \hline GI (score) & r = 0.43 & r = -0.09 \\ \hline PBI (score) & r = 0.62 * & r = 0.33 \\ \hline BOP (\%) & r = \(-\)0.04 & r = -0.12 \\ \hline \hline \end{tabular}
\end{table}