(Reuters Health) – Environmental factors seem to play a greater role than genetics in shaping the risk of children's caries, according to a study by Australian twins.
The researchers followed 345 twins from 24 weeks of gestation over six years of age, when they all had dental examinations. At six, 32 percent of children had tooth decay, and 24 percent of children had advanced cavities.
To see how genetics can shape the risk of caries, researchers have seen how often two children get caries in pairs of identical twins – who have identical genetic variations – and fraternal twins – who usually have about half of their variations.
The risk of both brothers and sisters who develop any form of tooth decay or advanced cavities were similar to identical and fraternal couples, suggesting that genetics does not explain much of the risk to these oral health problems.
"Therefore, risk factors appear to be predominantly ecologically and potentially modified," says lead author of the study, Mihiri Silva of the University of Melbourne and the Murdoch Children's Research Institute at the Royal Children's Hospital in Melbourne.
"This could reveal the idea that individuals are genetically destined to have bad teeth and should drive us to find ways to solve risk factors that we know are important for teeth health," Silva said via e-mail.
In the world, about 60 to 90 percent of school-age children have tooth decay, which can potentially result in pain, infection and hospitalization, researchers in pediatrics say. Also, a toothache can result in school absence, poor nutrition, compromised growth and development, and poor quality of life for children and parents.
Children's cavities are also the strongest indicator of poor oral health in adulthood, the study team writes.
While some previous research has questioned the role that genetics can play in causing caries, research has so far not provided a clear picture of what role environmental factors or lifestyles can play in this risk.
In the current study, the two twins had cavities in 29 pairs; in another 33 pairs of twins, only one child was hit.
The two children had advanced cavities in 26 pairs of twins, and another 31 pairs had only one child with advanced cavities.
In particular, three environmental factors affecting the risk of caries: maternal obesity, defects in the mineralization of tooth enamel and lack of water fluoridation in the community.
The study was not a controlled experiment designed to prove whether or how any of these factors can directly cause decay of teeth or cavities.
However, maternal obesity may affect children's risk of oral health problems due to common dietary habits or the way of living in the household or the biological processes affecting the susceptibility to teeth problems, said Silva. For example, obese mothers may be more likely to feed children with unhealthy foods, which can contribute to caries.
Meanwhile, fluoridation of drinking water has been proven to reduce the risk of caries, but is not universally available in public drinking water.
And defects in the mineralization of the dental enamel that lead to a weak enamel that can easily fall apart and form cavities can begin to develop in the uterus and in early childhood. This can be caused by certain medications that women take during pregnancy or early childhood, as well as from poor nutrition and certain early childhood illnesses.
The good news is environmental factors as this can be controlled to improve oral health.
"Based on the findings of all existing research – including ours – parents and families should focus on practicing healthy habits in general, including low-sugar diets and regular tooth brushing," Silva advised.
Enamel defects "can be detected and treated early to reduce problems, so children with initial dental examinations at the start of a year can minimize problems later," Silva added. "Our study also shows that public health initiatives such as water fluoridation in the community continue to be important for the prevention of dental caries."
Source: bit.ly/2W8UAVl Pediatrics, online April 26, 2019.