Abstract
Background: Periodontitis is a destructive chronic inflammatory disease causing irreversible loss of tooth-supporting tissues. Prostaglandin-endoperoxide synthase 2 (PTGS2) is an important inflammatory mediator that is overexpressed in periodontitis as well as other diseases. Periodontitis may contribute to an elevated plasma PTGS2 level.

Aims: To determine the level of PTGS2 in the plasma of chronic periodontitis patients in comparison to periodontally healthy controls. Also to investigate whether there is any correlation between PTGS2 plasma levels and clinical periodontal parameters.

Methods: Blood samples were collected from 60 chronic periodontitis (CP) cases (moderate to severe periodontitis) and 60 periodontally healthy controls. A questionnaire was used to collect information from each participant. Clinical Periodontal parameters were recorded. Blood samples were collected in EDTA containing tubes and centrifuged to obtain plasma samples which then were frozen at -70c. ELISA was performed to determine the PTGS2 level in the plasma samples.

Results: The mean clinical attachment loss (CAL) was 4.35mm in the CP cases. ELISA analysis showed a statistically significant elevation of PTGS2 concentration in the plasma of periodontitis cases compared to controls (p=0.001). However, the Person correlation coefficient revealed a negative correlation between PTGS2 plasma concentration and the clinical periodontal parameters in both cases and control groups.

Conclusion: Periodontitis may contribute to elevated plasma levels of PTGS-2 whose elevation is related to other diseases such as osteoarthritis, atherosclerosis, proliferative diseases, and preterm delivery. However, longitudinal studies and intervention trials are needed before any causative role can be assigned.

Key words: chronic periodontitis, plasma prostaglandin-endoperoxide synthase 2, correlation.