Toothpaste almost always contains an abrasive, fluoride and, in many cases, a foaming agent. Fluoride has been shown to have a mild antibacterial effect, and there is hardly any research into the effects of other toothpaste ingredients on oral bacteria. Foaming agents, for instance, are known to dissolve the oral mucosa, which modifies the circumstances in the mouth, although it is not clear if that causes shifts in the bacterial population. The actual brushing action itself could possibly be the most disruptive factor: the mechanical removal of dental plaque. It could be that by brushing their teeth, people’s oral health becomes dependent on it, whereas allowing one’s oral flora to develop a natural balance may make brushing superfluous.
However, according to Crielaard, how to maintain the ideal balance still remains “the billion dollar question”. Predisposition plays a role, but the single most important factor is diet. If someone consumes a lot of sugar and not enough fibre-rich foods, such as raw vegetables that remove impurities, they will have no other option but to use a toothbrush. In 2009, other researchers already presented evidence that people following a “Palaeolithic” diet do not develop gingivitis, despite not brushing their teeth. But as long as there is no conclusive evidence that brushing healthy teeth is actually harmful, people are still advised to brush twice a day.
This article was previously published in Volkskrant supplement Sir Edmund on 24 September 2016.