Identification of Gingival Crevicular Fluid Sampling, Analytical Methods, and Oral Biomarkers for the Diagnosis and Monitoring of Periodontal Diseases: A Systematic Review

Table 1

Summary of washing techniques used in the GCF collection.

Reference	Analysis	Markers	Aim	Main findings
[8]	ELISA, spectrophotometer; (SPM)	IL-1β, IL-18,; elastase activity	To evaluate inflammatory activity in GCF in RA patients and patients without RA.; To determine if the periodontal inflammation reduced after RA treatment.	RA anti-inflammatory treatment reduced periodontal inflammation.
[9]	Capillary zone electrophoresis coupled with laser induced fluorescence detection; (CZE-LIFD)	Arginine, glutamate	To evaluate the glutamate and arginine GCF levels in adult chronic periodontitis (CP) patients against healthy controls.; To compare two types of microdialysis probes: U-shaped probes and normal.	Arginine level was elevated and glutamate level was decreased in CP patients, compared to healthy subjects.; No statistical differences were found between the U-shaped and normal probes.
[10]	Polymerase chain reaction	Host β-globin gene fragments	To determine the expression of gene fragments of the host β-globin in GCF at different stages of periodontal disease.	Periodontal diseases have marked effect on gene fragment expression in GCF. Thus β-globin DNA could be used as a biomarker for periodontal disease.
[11]	ELISA	MMP-8,; MMP-9	To determine the association between the existence of subgingival microorganisms in certain locations and the GCF levels of MMP-9 and MMP-8.	The existence of subgingival microorganisms in GCF, mainly T. denticola, increased the MMP-9 and MMP-8 levels.