Periodontitis is a chronic inflammatory disease involving
interactions between complex microbial biofilms, many
cell populations and inflammatory mediators, leading to
the destruction of the tooth-supporting structures like
the periodontal ligament and the alveolar bone [1]. Besides
being a common cause of tooth loss, severe periodontitis
(about 8.5 % of patients) can detrimentally
affect systemic health, as it can increase the patients’ risk
for diabetes, atherosclerosis, rheumatoid arthritis, and
adverse pregnancy outcomes [2–4]. Two major clinical
entities of periodontitis are currently recognized: chronic
periodontitis, which is more common, and aggressive
periodontitis, a clinically challenging entity featured by
an early onset and a rapid progression [5]. The underlying
etiology of both the two forms has not been fully
elucidated. Therefore, gaining further insights into the
molecular mechanisms of periodontitis will be of great
significance for the treatment of periodontitis.
Previous studies have demonstrated that factors that
may determine the presence and rate of progression of
periodontitis are complex, which can be defined as the
interplay of numerous parameters acting simultaneously
and unpredictably [1]. For instance, the tooth-associated
microbial biofilm or dental plaque is essential but not
sufficient to induce periodontitis. The host inflammatory