## 4 Discussion  
Both periodontitis and CKD represent public health issues, with a compelling influence upon the life-quality of patients and their survival rate. Studies analyzing the interrelationship between these two entities are unsystematized, currently suggesting a bidirectional path [13; 14; 15; 32]. This trajectory is primarily due to common inflammatory  
Figure 2: Comparison between inflammatory biomarkers in group 1 vs. group 2 (min—minimum value, max—maximum value, **—**statistically significant difference). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Periodatitis**} & \multicolumn{3}{c}{**TNF-\(\alpha\) (pg/mL)**} & \multicolumn{3}{c}{**IL-1\(\beta\) (pg/mL)**} & \multicolumn{3}{c}{**MMP-8 (ng/mL)**} \\ \cline{2-7}  & \multicolumn{4}{c}{**Mean Values**} \\ \cline{2-7}  & **Group 1** & **Group 2** & **Group 1** & **Group 2** & **Group 1** & **Group 2** \\ \hline Stage 1 (mild) & 27.40 & 2.10 & 30.30 & 10.70 & 7.70 & 5.50 \\ \hline Stage 2 (moderate) & 23.50 & 2.00 & 39.15 & 14.40 & 32.65 & 5.70 \\ \hline Stage 3–4 (severe) & 22.55 & 2.15 & 29.40 & 9.25 & 18.35 & 5.20 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: GCF immune biochemical biomarker levels in study group versus control group in correspondence to periodontitis staging. mechanisms--bacteremia, production of cytokines and other proinflammatory molecules, oxidative stress and endothelial dysfunction [33]. Upon an exhaustive inspection of the literature data, one can realize the existence of narrow number of research aiming at the analysis of oral health status in patients with CKD, especially in the terminal stages. In subjects with CKD treated with hemodialysis or peritoneal dialysis and associated with untreated periodontitis, the risk of mortality is augmented significantly [34]. The inflammatory condition in CKD is characterized by the activation of soluble factors such as cytokines and chemokines (chemotactic cytokines). Moreover, the relationship between periodontitis and CKD, by reference to the common inflammatory status, is a topic of constant interest for specialists in the two fields. Several studies published in the main flow attest that periodontitis mediates the immune response in hemodialysis patients [13; 28; 29]. Among the cytokines involved in the systemic inflammatory mechanisms, TNF-\(\alpha\) is part of the acute phase proteins produced by activated macrophages, but also by other cell types (i.e., CD4 T lymphocytes, NK cells, neutrophils, mast cells, eosinophils, neurons, fat and heart cells) [35; 36; 37; 38]. IL-1 family members include 11 cytokines that regulate and initiate the inflammatory response through integrins expression modulation over leucocytes and endothelial cells and allowing immune competent cells to pass towards the infection site [39; 40]. MMPs are a group of 24 endopeptidase with intracellular calcium ion-dependent action, who contain zinc in their structure [41]. These enzymes are capable of degrading all types of extracellular matrix proteins but can be implicated in the processing of bioactive molecules, as well. The most common classification of MMPs includes 5 main groups: collagenases, gelatinases, stromlysines, matrilysin and membrane type MMPs [41]. Collagenases are capable of degrading fibrillary collagen and comprise MMP-1, MMP-8, MMP-13, MMP-14 and MMP-18 [41]. The literature confirms the association between cytokines (TNF-\(\alpha\), IL-1, IL-6, IL-8, IL-17), periodontitis, and CKD [13; 25; 26; 28]. In CKD, high serum levels of TNF-\(\alpha\) are reported in relationship with the metabolic syndrome, cardiovascular disorders, congestive cardiac failure, progression and disease mortality [42; 43; 44; 45], being considered a sensitive marker for periodontal inflammation [46]. In periodontitis, the data about TNF-\(\alpha\) serum and/or crevicular fluid dynamic are contradictory.