## 4 Discussion  
Plasmatic determinations can be done for both cisplatin forms (protein bound or free circulating) [19], but also for the total plasmaatic platinum quantity [20]. Plasma levels  
Figure 4: Mean values of chemotherapy drugs detected at T0, T1 and T2 in saliva. (**a**) Mean values of cisplatin concentration (\(\upmu\)g/mL); (**b**) mean values of oxaliplatin concentration (\(\upmu\)g/ml); (**c**) mean values of gemcitabine concentration (\(\upmu\)g/mL). \begin{table}
\begin{tabular}{c c c c c c c} \hline  & & **N** & **Mean Rank** & **Rank Sum** & **Z Statistics** & **p Significance** \\ \hline \multirow{3}{*}{Saliva chemotherapy in T1 compared with T0} & Negative ranks & 2 & 28.50 & 57.00 & \(-\)3.475 & **0.001**, **SS** \\  & Positive ranks & 27 & 14.00 & 378.00 & & \\  & Pairs & 0 & & & & \\  & Total & 29 & & & & \\ \hline \multirow{3}{*}{Saliva chemotherapy in T2 compared with T0} & Negative ranks & 2 & 26.50 & 53.00 & \(-\)3.277 & **0.001**, **SS** \\  & Positive ranks & 25 & 13.00 & 325.00 & & \\ \cline{1-1}  & Pairs & 2 & & & & \\ \cline{1-1}  & Total & 29 & & & & \\ \hline \multirow{3}{*}{Saliva chemotherapy in T2 compared with T1} & Negative ranks & 27 & 14.00 & 378.00 & \(-\)4.546 & **0.000**, **SS** \\  & Positive ranks & 0 & 0.00 & 0.00 & & \\ \cline{1-1}  & Pairs & 2 & & & & \\ \cline{1-1}  & Total & 29 & & & & \\ \hline \end{tabular}
\end{table} 
Table 3: Wilcoxon test for chemotherapy concentration comparison in T0, T1, and T2. of cisplatin become undetectable after 24-25 h post administration where the infusion duration was 0.5 h, as was the case in the present study, and highest concentrations in plasma were obtained in the first hour post administration the peak being at 30 min for both bound and free cisplatin [18]. The lowest concentration values determined in saliva in this present study were registered in T0, the highest were found to be in T1 right after administration at 30 min and then lowered again at 2 h (T2) after the administration was completed. These results confirm the presence of chemotherapy in the oral cavity and saliva in small quantities that follow a value curve similar to the plasmatic curve, and in the case of oxaliplatin it can still be detected in saliva even after a longer period of time, such as the end of the cycle between two administrations in our current study and coincides with our determinations in T0. Clinical evaluation, which included the GI, GBI and CPITN indexes, alongside PD and CAL, partly reflected the level of hygiene and also offered a detailed view of the periodontal status in chemotherapy patients. Even though we did not achieve statistically significant results in correlating the presence of chemotherapy concentrations found in saliva with periodontal status, it has been stated in the literature that during chemotherapy there is a higher chance of infections occurring locally that can extend systemically [21,22]. Moreover, it has been proven that chemotherapy can influence the salivary immunoglobulins by decreasing IgG and IgA levels which in turn can partly explain the patient's susceptibility to oral infections [23]. The oral microbial community is influenced by chemotherapy as well as some saprophytic bacteria can become aggressive due to a decrease in granulocytes and increased fragility of the oral mucosa [24]. As necrotizing gingivitis is one of the more frequent forms of periodontal manifestations, it has been shown that certain bacteria, such as Prevotella, Fusobacterium, Actinobacillus, Actinomycetemcomitans and Actinomyces, are associated with infections occurring in patients receiving chemotherapy [25]. On the other hand, it was shown in the past that periodontal status can influence the microbial composition during chemotherapy [26]. The most important periodontal modification was observed on the mandible in our study, where the most extensive losses were registered at 36, 41, and 44 (mean CAL = 3.214, 3.308, and 3.163 mm, respectively).