In a study published in The BMJ today, researchers found that exposure to secondhand smoke as an infant as young as 4 months is associated with increased risk of tooth decay at age 3, according to Medical News Today.
Preventing tooth decay in young children tends to focus on restricting sugar, supplementing with oral fluoride and fluoride varnish. However, studies suggest that secondhand smoke plays a part in the development of cavities, which can result from a number of factors that include physical, biological, and environmental and lifestyle.
A big part of oral health is the acquisition of Streptococcus mutans (S. mutans), that produce acids from the sugar one consumes, dissolving the hard enamel coating on teeth. The age of highest risk for these bacteria is at 19-31 months.