The action of our immune system against oral bacteria could be at the origin of the formation of cavities, which could even affect teeth that have already been treated.
This is what can be called “collateral damage”: neutrophils, which are white blood cells (leukocytes) with a major role in our immune system, attack our teeth and even our oral bacteria which generate a risk of dental caries. Researchers from the University of Toronto (Canada) have just highlighted this phenomenon. Their work shows that neutrophils, which are therefore on the front line in our antibacterial defense, themselves produce acids which demineralize the teeth on which they are installed.
Streptococcus mutans causing cavities
Tooth decay is a common infection caused by the presence of bacteria in our mouth, especially that of the Streptococcus mutans, which is part of the commensal flora of the oral cavity. To counter these bacteria, our body sends neutrophils to the mouth, which enter the teeth through our gums and destroy the intruders that cause cavities. But these neutrophils are so aggressive that they damage their own local environment, which in this case is the teeth themselves. “It’s like using a hammer to kill a fly on a wall,” says Yoav Finer of the University of Toronto.
Teeth weakened by demineralization
How can the remedy ultimately be the cause of the evil? When neutrophils attack oral bacteria, they produce acids which contribute to the demineralization of teeth. This causes an association between the enzymes of neutrophils and those of bacteria. And teeth weakened by demineralization become very vulnerable targets for this association. This then results in the appearance of cavities because of the cells that are supposed to avoid them.
And this infuriating observation even extends to treated teeth. Indeed, neutrophil enzymes would also attack the composite resins used to seal decayed teeth, which would explain the reappearance of cavities on teeth that have already been treated.
