Identifying the bacteria that cause cavities

The oral microbiota varies depending on how healthy your teeth are (whether or not you have cavities) but we still don’t fully understand how it changes when a cavity forms.


The sugars we eat are fermented by bacteria in the dental plaque, which makes the mouth more acidic. When it happens repeatedly, this process leads to the selection of pathogenic bacteria that cause cavities. 

A team wanted to identify the different species living in the dental plaque of young children with varying cavity status: some had no cavities, some had cavities that affected the enamel, and others had cavities that reached the dentin. The aim was to see if the microbial profile is specific to the damage, and whether it changes or remains stable over time.

The analysis shows very different microbial profiles between healthy teeth and teeth with cavities, and confirms the consensus that the Streptococcus sanguinis bacteria is associated with good dental health and Streptococcus mutans with the development of cavities. The analysis also reveals an increase or decrease in the proportion of certain bacteria in parallel with the worsening of the cavity, and suggests that certain species only appear when a cavity is already at an advanced stage. Furthermore, in children with cavities, the oral microbiota of their healthy teeth is closer to that of their cavity-affected teeth than to that of a healthy tooth from a child without any cavities, which exposes them to an obvious cavity risk. These numerous discoveries should promote the development of new strategies to identify and treat children with an increased cavity risk.


Richards, Alvarez et al. 2017. Microbiomes of Site-Specific Dental Plaques from Children with Different Caries Status. Infection and Immunity, auguste 2017, vol 85, issue 8.