Abstract
The small signalling molecule nitric oxide (NO) has been postulated to have a mediator role in the pathogenesis of several diseases including oral lichen planus (OLP). This systematic review aimed to quantify the existing literature and assess the association of NO and OLP.
The focused question being addressed was "Is there an association between nitric oxide and OLP?" PubMed, EMBASE, Scopus, and Web of Science, and grey literature from January 1990 to August 2018 were searched. Two independent reviewers performed the study selection using specified eligibility criteria.
Seven studies that met the eligibility criteria were included. All of these were case-control studies and 151 patients with OLP were evaluated (mostly females), with an age ranged from 20 to 75 years. The included studies showed a significant higher NO levels in OLP patients compared to the healthy controls, with two studies demonstrated a higher NO levels in erosive OLP compared to non-erosive OLP.
These findings support that an association exists between higher NO concentration and OLP. However, larger high-quality studies with refined methodological design are needed to confirm the role of NO in the aetiology and pathogenesis of OLP.