The incidental discovery of apical periodontitis

Apical Periodontitis Is Associated with Elevated Concentrations of Inflammatory Mediators in Peripheral Blood: A Systematic Review and Meta-analysis

INTRODUCTION

Apical periodontitis (AP), except for the local known consequences, may also be a systemic burden. Circulating inflammatory mediators that are released to sustain the AP lesion can in theory harm other bodily tissues. The aim of this systematic review was to summarize the existing evidence on the influence of AP on the peripheral blood levels of inflammatory mediators and markers of systemic stress.

METHODS

A search of MEDLINE-PubMed, Embase, and Cochrane was conducted up to and including February 2019 to identify studies in 5 different languages. The Newcastle-Ottawa Scale was used for quality assessment of the included studies.

RESULTS

Twelve of the 20 included studies were case-control studies, and 8 were intervention studies. The data of all the included studies were analyzed descriptively, whereas the data of 11 studies were available for meta-analyses. The study designs were heterogeneous. Nevertheless, the meta-analyses revealed statistically significant differences in C-reactive protein, interleukin 6, and asymmetric dimethylarginine levels between AP subjects and controls in peripheral blood. In addition, the concentration of C3 complement fragment in peripheral blood was significantly lower after the treatment and resolution of AP than before.

CONCLUSIONS

The existing literature indicates that AP adds on to systemic inflammation by elevating C-reactive protein, interleukin 6, asymmetric dimethylarginine, and C3 levels. In order to overcome the issue of large variation between study designs, future studies should have clear inclusion criteria, preferably larger cohorts, adequate follow-up of all subjects, and a thorough presentation of the data to enable further exploration of the possible burden of AP on general human health. Nevertheless, there is now stronger evidence that AP contributes to low-grade systemic inflammation.

Does apical periodontitis have systemic consequences? The need for well-planned and carefully conducted clinical studies

Apical periodontitis, infection of the root canal system, may have systemic consequences. This proposal has been brought forward many times in dentistry literature but the general consensus is that there is no scientific basis for an association between endodontic infections and general health. This opinion paper argues that, in order to obtain such a scientific basis, or to rule out the issue all together, we need carefully designed longitudinal challenge model (that is, intervention) studies in which we follow specific biomarkers of inflammation. These biomarkers can be those that are currently being substantiated in chronic inflammation and low-grade inflammation studies in medicine and nutritional science, where the presence of these inflammatory disorders is linked to systemic outcomes. A list of suggested biomarkers has been included.