Why Children Get Cavities, and Why They Spread Faster
Cavities in children form the same way they do in adults. Bacteria in the mouth feed on sugars from food and drink, produce acid, and that acid slowly dissolves the enamel until a hole forms. What makes cavities in kids different is speed. The enamel on a milk tooth is much thinner than on an adult tooth, so decay reaches the softer layer underneath far more quickly, sometimes within months rather than years.
Certain habits make it worse. Bedtime bottles of milk or juice, frequent snacking, sugary drinks in the heat, and the gap between when a child starts brushing alone and when they are actually good at it, usually around age seven. The back molars are the most common site, because the grooves on their chewing surface trap food that a child's brushing misses.
This is why a cavity in a milk tooth still needs treating even though the tooth will eventually fall out. An untreated cavity reaches the nerve, causes pain and infection, and can damage the adult tooth still forming in the gum underneath. Losing a milk tooth early also lets the neighbouring teeth drift into the gap, which is one of the most common reasons a child later needs braces.
