Public health

Bedtime bottles may cause cavities in baby teeth

Putting a baby to bed with a bottle of milk can cause cavities to form in those tiny teeth. “Parents know that sugary foods cause cavities, but may not realize that milk also contains lactose, which is a sugar. Giving your baby a bottle of milk every night at bedtime increases the risk of cavities,” explains Chantal Galarneau, who recently submitted a doctoral thesis to the Université de Montréal on how mothers’ attempts to soothe their babies can cause cavities.

Is the practice of giving babies a bedtime bottle widespread? Yes, according to the study Galarneau conducted in the Department of Public Health in the Faculty of Medicine. In a population of 776 mothers from the Montérégie, 29% reported giving their babies a daily bottle to help the infant get to sleep. A soothing habit, yes – but one that can leave clear traces on those baby teeth. 

When saliva flow is reduced during the night, the cleansing effect saliva usually has in the mouth is also reduced. Since micro-organisms are not dislodged, they have time to work on the teeth and cause cavities – especially if the baby’s teeth weren’t brushed before bed.
Cavities in preschool-aged children are known as early childhood cavities. “It’s considered an infectious disease. The bacterium that is primarily responsible, Streptococcus mutans, is not found in babies’ mouths at birth. It’s frequently transmitted through the saliva of an adult or another child,” Galarneau notes.

The combination of bacteria and sugar with growing teeth is harmful to children’s health. The longer bacterial transmission can be delayed by trying not to share food, utensils, or toothbrushes, the better the child’s dental health is likely to be. “For sure, the baby will have bacteria at some point, but it’s much better if that happens later,” says Galarneau, adding that an occasional bottle poses less of a risk than a regular bedtime bottle routine.

Of course, it’s not always easy for parents to stand by while a crying baby resists going to bed. When lullabies or singing don’t do the trick, some parents will give their infant a sugary drink or a sweet treat.  Galarneau wonders why, when clearly these practices can cause cavities. She believes that at bedtime, tired parents are more likely to resort to such solutions. Her study also shows that poverty has a great deal to do with it. More than 59% of mothers in poor households give their children bottles or treats to put them to sleep, compared to 38% of mothers in more well-to-do households.

“If we hope to change behaviour, we shouldn’t stop at education and awareness programs. We need to reach people in poor neighbourhoods and work on all aspects of their lives,” Galarneau says. The best way parents can foster their children’s dental health is by providing healthful snacks, such as fruit, and seeing their dentist on a regular basis.