Where do tooth decay bacteria come from? When is it most likely? We asked a dental expert Spoons, tableware, and kisses Parents' saliva is infectious 19 to 31 months old when baby teeth begin to grow is the ``window of infection'' Some dentists say ``diet is everything'' rather than tooth brushing Sukusuku Voice Ranking Featured by the editorial team! Sukusuku voice

A hippo brushes its teeth to prevent tooth decay at Tobu Zoological Park in Miyashiro Town, Saitama Prefecture (photographed in May 2010)

Cavity bacteria feed on carbohydrates such as sugar contained in food and produce a strong acid. This acid dissolves the enamel on the surface of your teeth and creates cavities.

　The representative of caries bacteria is Streptococcus mutans. It does not exist in the mouth of a newborn baby and is transmitted through the saliva of parents. Paths include reusing spoons, cups, and utensils, and kissing as an expression of affection.

Typical caries bacteria, mutans streptococci

19 to 31 months after birth, which is called the "window of infection", is important to prevent cavities. About half of carriers become established during this period. It takes several days for the infection to settle in the mouth, so if an adult brushes their teeth properly, it can be prevented.

6 to 12 years old are most prone to tooth decay. In particular, preventing the colonization of newly growing back teeth by bacteria "reduces tooth decay even as an adult," says Mr. Hosaka. Preventative measures include applying fluoride and filling the fine grooves of the teeth with cement or resin.

　Eating habits are even more important. In children and adolescents, it is sugar control. Even if you have cavities, if you don't have sugar, you can't make a strong acid that can break through the enamel. Some dentists say that diet is more important than brushing teeth.

Normally, the inside of the mouth is kept neutral by the action of saliva, but when you eat, it becomes acidic and your teeth are easy to melt. If you eat too many sweets or eat too many snacks, you won't have time to return to neutrality, and you're more likely to get cavities.

Assistant Professor Keiichi Hosaka, Graduate School of Tokyo Medical and Dental University

Mr. Hosaka said, "Avoid between-meal snacks that contain sugar. If you want to eat something sweet, it would be a good idea to have it as a dessert after your meal or use artificial sweeteners wisely. However, as you get older, your enamel The roots of the teeth that are not covered by the wax are exposed, and even the starch in the rice can cause tooth decay, which is troublesome. Regular visits to the dentist's office are important."