Epigenetics has produced a high impact in biomedical research and is providing new biomarkers for the diagnosis and prognosis of diseases. In addition, epigenetics is also contributing to analyze the molecular causes underlying diseases, even so periodontal diseases as it has been recently reviewed. In this regard, changes in the methylation of genes codifying for pro-inflammatory and anti-inflammatory cytokines has been previously reported. miRNAs are very promising biomolecules to be used as biomarkers because miRNAs act as signaling molecules and participate in many biological processes, such as cellular development, differentiation, and apoptosis. The high stability of circulating miRNAs in the RNase-rich environment of the bloodstream and also in different biospecimens used in clinical routine, make these biomolecules an optimal source of candidate biomarkers. In fact, miRNAs have demonstrated their value as dynamic biomarkers in a wide variety of human diseases. Therefore, miRNAs can be used for the monitoring of periodontal disease.

The objective of this research is to analyze the levels of bone remodeling RANKL / OPG biomolecular markers, and the epigenetic regulation of these proteins to identify promising biomarkers of periodontal disease.

Material and Methods. Levels of RANKL and OPG will be measured in the gingival crevicular fluid (GCF) to assess the state of bone. These samples will be sent to the lab for quantification by ELISA method.

Furthermore, new epigenetic biomarkers based on the identification of high stable microRNAs will be identified by qRT-PCR in GCF as feasible tools for diagnosis and monitoring of wide range of disease, including periodontal disease.

Inclusion Criteria:

Group of periodontal patients:

1. Clinical criteria: at least 3 locations in unirradicular teeth with PD 6 mm. 3 samples will be taken from each of these 3 locations (9 total samples). Third molars are not included in the study.
2. Patients not treated periodontally.
3. 30-60 years.

Periodontally healthy group:

1. Absence of clinical and radiographical periodontal pathology.

Exclusion Criteria:

• Group of periodontal patients:

  1. Aggressive Periodontal Disease (Armitage, 1999).
  2. Patients with controlled periodontal disease with plaque and gingival indexes ≤20%.
  3. Patients with systemic diseases or taking medications that alter bone metabolism (Osteoporosis, arthritis, hormonal treatment, bisphosphonates, anti-inflammatory, immunosuppressants, etc ...).
  4. Patients with antibiotic, anti-inflammatory or contraceptive treatment in the previous 3 months or taking antiaggregants in the last 7 days before taking the sample.
  5. Smokers (> 10 cig. /day).
  6. Pregnant or breast-feeding.

Periodontally healthy group:

1. Patients with systemic diseases or taking medications that alter bone metabolism (Osteoporosis, arthritis, hormonal treatment, bisphosphonates, anti-inflammatory, immunosuppressant...).
2. Patients with antibiotic, anti-inflammatory or contraceptive treatment in the previous 3 months or taking antiaggregants in the last 7 days before taking the sample.
3. Smokers (> 10 cig/day).
4. Pregnant or breast-feeding.

Patients attending to the university who meet the inclusion criteria.