**3.4 Biomarkers determined in serum**

Serum in humans is a matrix commonly used in clinical and biological studies. Many authors recommend using the correct matrix. Both plasma and serum are derived from whole blood that has undergone different biochemical processes after blood extraction. The serum is obtained from the blood that has been clotted [84].

### *3.4.1 Proteins (cytokines) involved in the inflammatory process of periodontitis*

In a study conducted by Nile et al. [85], interleukin IL-17 was identified as a reliable biomarker in 40 patients with chronic periodontitis, later these subjects underwent periodontal therapy, and the values of this interleukin decreased; thus, they consider that IL-17 can be a valuable protein to monitor healing processes after a periodontal intervention.

Another protein related to the immune response MCP-1 was studied by Boström et al. [86]. They studied healthy patients with periodontitis and detected that the MCP-1 protein was increased in the serum and inflamed connective tissue comparing it with healthy patients. In this way, they considered that MCP-1 can help identify patients with periodontitis.

#### *3.4.2 Metalloproteinases*

Within the metalloproteinases studied in serum, Lira et al. [65] reported that MMP-8 is elevated in patients with aggressive generalized periodontitis compared with the rest of the patients.

#### *3.4.3 Oxidative stress*

Sreeram et al. [87] studied the transpeptidase biomarker (GGT) in healthy subjects and with periodontitis. This biomarker showed elevated levels in patients with periodontitis with respect to healthy. Among the conclusions found in this study was the GGT is useful, economic, and easy to use.

Onder et al [88] studied 4-hydroxynonenal (4-HNE) as a biomarker in serum, concluding that biomarker 4-HNE was at high levels in patients with periodontitis.

In another serum study, other biomarkers of oxidative stress as total antioxidant capacity (TOS) and oxidative stress index (OSI) used in patients with periodontitis and healthy found high levels of TOS and OSI in patients with chronic periodontitis, this suggests that these biomarkers play important roles in periodontitis [89].

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*Use of Biomarkers for the Diagnosis of Periodontitis DOI: http://dx.doi.org/10.5772/intechopen.85394*

**3.5 Biomarkers determined in plasma**

Calprotectin was studied by Lira et al. [65]; this biomarker was analyzed in patients

Blood can be a universal reflection of the state or phenotype. Its cellular components are erythrocytes, thrombocytes, and lymphocytes. The liquid portion is called plasma, when all the components are retained. The concentrations of various plasma components are routinely determined in clinical practice [92]. In this way, it

Among the cytokines evaluated in plasma, we can say that IL-8 and IL-10 were useful to discriminate patients with aggressive periodontitis from healthy ones, and we can add that they were interleukins different from those expressed in the

On the other hand, IFN-γ is a biomarker that has been determined in plasma and was significantly high in patients with aggressive periodontitis, this correlates with the findings in crevicular fluid where this biomarker was elevated in sick patients [78]. Regarding MIP-1α, when it was determined in plasma, it was determined that it could be useful to discriminate patients with aggressive periodontitis from healthy

Periodontitis is one of the most prevalent illnesses in humans [93]. One of the main challenges faced by the periodontics field is to improve the methods for diagnostic and prognostic of periodontitis [94]. Biomarkers, previously described, can be useful in monitoring the current state of the disease, the effectiveness of the treatment, and possibly predict the progression. However, currently the single ideal biomarker displaying high specificity and sensitivity for discriminating and monitoring this disease has not been determined. Thus, the combination of different biomarkers could be more advantageous than single biomarkers [93]. This would provide a more accurate panorama of the state of periodontal disease.

Classic methods for periodontitis diagnosis as the inspection and the palpation by the specialist can be relatively inaccurate. Additionally, the use of periodontal probes, and radiography could only provide information about previous periodontal damage rather than the current state [93]. Thus, biomarkers have been proposed as complementary methods to defeat the mentioned limitations monitoring the

Desirable's characteristics in test using biomarkers in periodontitis are easy to perform, rapid, and low cost, which could allow clinicians to perform early diagno-

*3.5.1 Proteins (cytokines) involved in the inflammatory process of periodontitis*

with aggressive generalized periodontitis, found elevated levels in these patients compared with healthy and with gingivitis. In addition to the previous study, Nizam et al. [90] studied myeloperoxidase (MOP) and found that it increases in patients with generalized periodontitis compared to healthy ones; nevertheless Meschiari et al. [91] reported similar levels in patients with periodontitis and healthy. This discrepancy between both authors is possible due to the demographic variation and probably the

anatomical site where the sample was extracted for analysis.

is not surprising that biomarkers are sought in plasma.

crevicular fluid where IL-2 and IL-6 were relevant [78].

clinical response to an intervention and future risk [95].

sis and more effective personalized treatment.

ones, since it was found to be elevated [78].

**4. Discussion**

*3.4.4 Others*
