Study identifies asymptomatic state of gingivae that links gingivitis, periodontitis and ageing
QINGDAO, China: Most adults experience episodes of gingivitis, which can progress to periodontitis, yet the role of plaque in gingivitis onset and progression to periodontitis remains uncertain. Now, researchers from the Qingdao Institute of Bioenergy and Bioprocess Technology (QIBEBT) of the Chinese Academy of Sciences (CAS) have observed that the oral health of participants deteriorated and their oral microbiome aged more rapidly than normal after they stopped practising oral hygiene.*
The study included 40 participants with different levels of naturally occurring gingivitis, who were asked to perform optimal oral hygiene for three weeks in order to establish a baseline for the examination. In the next step, the participants’ oral hygiene was interrupted for 28 days, and an experimental gingivitis was induced.
The researchers performed genetic analyses of the bacterial population in the participants’ gingivae. In addition, chemical analyses of the molecules produced by the bacteria were performed, and the immune responses of the study participants were recorded.
Within 24 to 72 hours after oral hygiene was discontinued, the research team observed a decrease of Rothia species bacteria and of the chemical betaine, which has been reported to play an anti-inflammatory role in several inflammatory diseases. The researchers assume that owing to the positive link to betaine and the negative association with gingivitis severity, Rothia is perhaps beneficial to gingival health and potentially contributes to betaine metabolism in plaque.
Additionally, participants’ gingivae showed a rapid activation of several salivary cytokines, which are produced by the immune system and associated with inflammation. At the same time, the presence of bacteria associated with periodontitis increased significantly, even though there were not yet any apparent symptoms of the disease.
“[The participants’] oral microbiome had aged the equivalent of about a year in less than a month” – Prof. Jian Xu, QIBEBT
In a press release by CAS, lead author Prof. Jian Xu, director of the Single-Cell Center at QIBEBT, said: “We also found a sudden ageing of the bacteria in the mouth. Their oral microbiome had aged the equivalent of about a year in less than a month.”
Previous studies have shown that the composition of the oral microbiome may indicate a patient’s age. With increasing age, certain types of oral bacteria decline—for example Rothia species bacteria.
The researchers explained that their findings demonstrate “a crucial link between gingivitis, periodontitis, and healthy ageing”. They stated: “A significant portion of world population still fails to brush teeth daily. As a result, the majority of the global adult population is afflicted with chronic gingivitis, and if it is left untreated, some of them will eventually suffer from periodontitis.”
The researchers concluded: “Our findings underscore the importance of intervening at [an early] stage of gingivitis via proper oral-hygiene practices on a daily basis, so as to maintain a periodontitis-preventive plaque and ensure the healthy ageing of the oral ecosystem.”
The study, titled “Longitudinal multi-omics and microbiome meta-analysis identify an asymptomatic gingival state that links gingivitis, periodontitis, and aging”, was published on 9 March 2021 in mBio.