In that regard, the present study showed that MPO and PMN elastase persisted in elevated levels in patients with periodontitis compared to healthy controls after the treatment phase, which may suggest the eventual elevation of aMMP-8 levels and the eventual elevation of periodontitis disease activity in the future that can be monitored by the aMMP-8 POCT in the periodontitis treatment and maintenance phases. Here, MPO is linked to periodontitis.