How can cavities be contagious? Remember that bacteria are behind tooth decay, and bacteria can be transmitted from one person to another -- for example, by saliva. If a baby's caregiver (usually the mother) cleans the baby's pacifier by putting it in her own mouth, or shares a spoon, she can transfer bacteria to the baby. The mutans streptococci are the most common germy culprits, although a new pathogen, Scardovia wiggsiae, was identified in February 2011 [source: ScienceDaily]. Prevention of ECC, then, starts with the parent. Treating a mother's caries helps avoid them in a child.
The next step to prevention is being careful of what foods and liquids go into a kid's mouth. Dipping a pacifier in honey or sugar is a bad idea, as is letting a kid sleep with a bottle, drink tons of fruit juice or soda, or breast-feed at will during the night. The American Dental Association recommends that children start drinking from a cup by the time they're 1 [source: ADA]. The organization also discourages use of a sippy cup for an extended period of time.
According to the National Institute of Dental and Craniofacial Research, cavities in baby teeth are more prevalent and more severe in black, Hispanic and poor populations [source: NIDCR]. Those populations are also more likely to be untreated.
Pedodontist James Hicks Jr. of Roswell, Ga., says that the dangers of untreated caries are serious. At the very least, not filling a tooth can lead to dental sensitivity, dental pain and an abscess that causes facial swelling, all factors that can affect a child's eating and speaking. At worst, infection can spread to the brain. A 12-year-old named Deamonte Driver died in February 2007 from an untreated tooth infection [source: Otto].
Even if a child simply loses the decayed tooth, it could affect how the permanent teeth grow in; if the space from the baby tooth isn't preserved, the permanent teeth will crowd each other. (That's why gaps between baby teeth are great, says Hicks -- kids with no spaces in their smile are more likely to need braces later on.)