According to a recent Australian study involving 250 pairs of twins, the idea that there is a genetic predisposition to tooth decay is unfounded.
Tooth decay does not depend on DNA, in other words on an inherited trait, but on environmental factors (dental hygiene, diet, fluoride exposure and so on).
Shedding light on the causes of this disease is a study recently published in the journal Pediatrics and led by Mihiri Silva of the Department of Paediatrics at Melbourne Medical School in Australia.
The study, which involved 250 pairs of twins, collected demographic, health and phenotypic data starting from pregnancy (at weeks 24 and 36) and then periodically after the children were born until they turned 6, when the twin pairs had a dental examination.
Comparing identical twins (whose DNA is 100% the same) with non-identical twins (who share 50% of their DNA, like any two siblings) is a common way of establishing whether a given trait is genetic in origin or, on the contrary, depends on environmental factors (hygiene, lifestyle, diet and so on).
If a condition is genetic, identical twins should both have it to the same degree, and more often than non-identical twins do.
In the case of tooth decay, then, if there were an inherited predisposition, identical twins should more often than non-identical twins either both have decay or both be free of it.
This study found no clear differences between identical and non-identical twins, showing that genetics does not play a fundamental role in the development of tooth decay and highlighting the key role of eating habits and oral hygiene, starting from the prenatal phase, in preventing it.
Numerous studies have already shown that tooth decay is linked to frequent sugar intake, especially in liquid form, as in the sugary drinks often given to children instead of water, and how important it is to use fluoride toothpaste. This study also found that maternal obesity is a risk factor for tooth decay in children.
Periodontal disease is a different matter: a great deal of research has shown that it is 50% determined by genetics. Even so, for this disease too, keeping your habits in check, and your oral hygiene in particular, is essential for prevention.
References: Mihiri J. Silva, Nicky M. Kilpatrick, Jeffrey M. Craig, David J. Manton, Pamela Leong, David P. Burgner, Katrina J. Scurrah, Genetic and Early-Life Environmental Influences on Dental Caries Risk: A Twin Study
