Researchers from Sweden have made a novel discovery connecting highly variant types of the caries bacterium Streptococcus mutans to children with rampant caries and increased risk of tooth decay.
Their results are published in the journal EBioMedicine.
In a five-year study, in which saliva from a large number of children was analysed and their dental health monitored, the team from Umeå University established that some children have a more virulent variant of the caries bacterium, whose adhesive function makes it more aggressive and a better survivor.
“Caries is a lifestyle condition often caused by eating and oral hygiene habits that lead to an acidic pH in the mouth,” study author Professor Nicklas Strömberg said. “The pH level has a damaging effect on the enamel and further promotes the growth of acid producing bacteria such as Streptococcus mutans.”
This correlation is accurate for approximately four of five individuals who have small-to-moderate risk of developing caries. However, one in five—so-called ‘high-risk’—children in Sweden have an increased risk of developing caries, which the results now show is because they carry particular virulent variants of the S. mutans bacterium that may cause caries regardless of lifestyle.
The variants have unique adhesive proteins that improve the ability of the bacterium to survive the mouth’s antibacterial saliva.
Such high-risk children do not respond to traditional caries prevention or treatment, and lifestyle variables cannot predict the risk of caries.
Professor Strömberg said this new knowledge of the identified types of bacteria and how they initiate caries development “could be used to improve individualised dental care. The presence of the bacteria could be used as biomarkers for early detection of high-risk patients. Also, their adhesive function could constitute new targets for treatment.”