Collaborating researchers from the University of Pennsylvania School of Dental Medicine and the Adams School of Dentistry and Gillings School of Global Public Health at the University of North Carolina (UNC), have discovered that a bacterial species called Selenomonas sputigena (S. sputigena) can have a major role in causing tooth decay.
In the study, the researchers showed that S. sputigena, previously associated only with gum disease, can work as a key partner of Selenomonas mutans (S. mutans), which greatly enhances its cavity-making power.
The UNC researchers took samples of plaque from the teeth of 300 children aged three to five years, half of whom had caries, and analysed the samples using an array of advanced tests. The tests included sequencing of bacterial gene activity in the samples, analyses of the biological pathways implied by this bacterial activity, and even direct microscopic imaging. The researchers then validated their findings on a further set of 116 plaque samples from three to five year olds.
The data showed that although S. sputigena is only one of several caries-linked bacterial species in plaque besides S. mutans, and does not cause caries on its own, it has a striking ability to partner with S. mutans to boost the caries process.
The findings show a more complex microbial interaction than was thought to occur, and provide a better understanding of how childhood cavities develop, an understanding that could lead to better ways of preventing cavities. The researchers now plan to study in more detail how this anaerobic, motile bacterium ends up in the aerobic environment of the tooth surface.