The action of our immune system against oral bacteria could be at the origin of the formation of caries, which could even touch teeth already treated.
This is 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 at the University of Toronto (Canada) have just highlighted this phenomenon. Their work shows that neutrophils, which are therefore at the forefront of our antibacterial defense, produce themselves acids that demineralize the teeth on which they are installed.
Streptococcus mutans causing caries
Tooth decay is a common infection due to the presence of bacteria in our mouth, especially in the mouth. 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 intruders that cause cavities. But these neutrophils are so aggressive that they affect their own local environment, that 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 cause the harm? When neutrophils attack oral bacteria, they produce acids that help demineralize 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 results in the appearance of caries because of the cells that are supposed to avoid them.
And this raging statement extends even to neat teeth. Indeed, the neutrophil enzymes would also attack the composite resins used to seal the decayed teeth, which would explain the reappearance of caries on already treated teeth.