The influence of apical periodontitis on the concentration of inflammatory mediators in peripheral blood plasma and the metagenomic profiling of endodontic infections: Study design and protocol

Increased systemic inflammation has been identified in presence of oral disease, specifically endodontic disease. It is important to investigate whether treatment of the oral disease ameliorates systemic inflammation. Furthermore, there is no information about the extent to which different microorganisms may trigger inflammatory response. OBJECTIVES: Primarily (i) to compare the plasma concentrations of inflammatory mediators of apical periodontitis (AP) subjects to controls, (ii) to evaluate whether elimination of the endodontic infection reduces systemic inflammation (iii) to investigate the microbiome of root canal infections. Secondarily i) to correlate the inflammatory mediator data with the microbiome data to investigate whether the type of infection influences the type and severity of the inflammatory condition ii) to examine patterns in the inflammatory mediator data before and after tooth extraction in order to establish a biomarker signature of AP/oral disease. This is a multi-centre prospective case-control intervention study. The cohort will consist of 30 healthy human volunteers with one or two teeth with a root-tip inflammation and 30 matched healthy controls. Peripheral blood will be drawn at 6 time points, 3 before and 3 after the extraction of the tooth with apical periodontitis. The teeth will be pulverized, DNA extraction and sequencing will be performed. This study aims to compare the concentration of inflammatory blood plasma proteins in between AP-subjects and controls at different time points before and after the tooth extraction in a systematic and complete way. Additionally the composition of the root canal microbiome in association with the inflammatory response of the host will be assessed.