*3.4.4 Others*

*Periodontal Disease - Diagnostic and Adjunctive Non-surgical Considerations*

with periodontitis from healthy ones (p < 0.01) [79].

out periodontal disease of gingival health.

**3.4 Biomarkers determined in serum**

*3.3.8 Osteoprotegerin (OPG)*

been clotted [84].

a periodontal intervention.

*3.4.2 Metalloproteinases*

*3.4.3 Oxidative stress*

periodontitis.

with the rest of the patients.

identify patients with periodontitis.

of alveolar destruction [80]. MUC4 protein was measured in crevicular fluid and according to this study can be considered as a new biomarker to rule out patients

A final marker that we have considered for crevicular fluid is osteoprotegerin; this biomarker was studied by Kinney et al. [77]. They studied healthy patients, with gingivitis and periodontitis, finding that the biomarker OPG was elevated in patients with periodontal disease with a significant difference when compared with healthy patients, so they conclude that this biomarker has a good sensitivity to rule

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

*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

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

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

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

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

this suggests that these biomarkers play important roles in periodontitis [89].

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,

study was the GGT is useful, economic, and easy to use.

**28**

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