The study appeared in 2025 in npj Biofilms and Microbiomes. Its authors found AHL signals in dental plaque and used lactonase enzymes to break them down. The work points to a way to change plaque without trying to kill every bacterium inside it.
The bacteria appeared to produce AHL signals in the oxygen-rich environment above the gumline, while bacteria in more oxygen-depleted areas below the gumline were able to perceive them.
The mouth contains approximately 700 bacterial species.
Changing the conversation inside dental plaque
These organisms coordinate their behaviour through quorum sensing. Some oral bacteria use molecules called N-acyl homoserine lactones, or AHLs, to assess population density and organise collective activity. A collaborative team from the College of Biological Sciences and the School of Dentistry studied how those signals shape plaque.
The researchers detected AHL signals in dental plaque. They found one pattern above the gumline, where oxygen levels were higher, and another below it, where conditions were more anaerobic. That difference matters. The local environment can determine which organisms respond to the chemical messages.
The 2025 study remains a laboratory research finding: available reporting identifies no clinical trials, regulatory approval, or use of the method in patients. The authors plan to compare bacterial communication across different parts of the mouth and among people at different stages of periodontal disease.
The intervention did not simply remove bacteria. It changed the makeup of the community. Species more closely linked with oral health became more prominent instead of the entire microbial population being destroyed without distinction.
That matters.
Environment determines the effect of the signal
Oxygen changed the outcome. When the researchers blocked AHL communication in aerobic conditions, the share of health-associated bacteria rose. When they added AHLs in anaerobic conditions, disease-associated late colonisers became more favoured.
The same chemical language produced different effects in different environments. The findings are also described in the journal publication index.
Mikael Elias, an associate professor and senior author of the study, compared plaque development with the growth of a forest ecosystem. Early colonisers such as Streptococcus and Actinomyces are generally harmless and can support oral health.
As more species arrive, the community may move toward the so-called red complex. It includes Porphyromonas gingivalis and conditions linked with periodontal disease.
The comparison also separates this work from sterilisation. The goal is to push plaque toward an earlier, healthier state rather than remove the entire microbial population. That approach fits with the wider oral-care market described in an earlier market analysis, but it targets a deeper biological process.
The aim is prevention.
From laboratory finding to future prevention
The study does not establish a ready-to-use periodontal treatment. No patient treatment has been reported. The team plans to examine bacterial communication in different parts of the mouth and among people at different stages of periodontal disease.
Those studies will show whether selected enzymes can change plaque consistently enough to support future preventive strategies.
Elias also said the work could matter beyond the mouth. Microbial imbalances elsewhere in the body have been linked with various health issues, including some cancers.
The current evidence supports a narrower conclusion. Bacterial communication is a promising research target, but its effects depend heavily on oxygen and local ecology. Managing the community may prove more useful than destroying microbes indiscriminately. Clinical use still requires further research supported by the National Institutes of Health.
