Is Dental Decay Contagious?

Tooth decay is the single most common chronic childhood disease, despite also being preventable.

Is dental decay a contagious disease? 

Is it possible to catch it from someone else?

In a previous post we discussed what causes dental cavities. 

To summarise, bacteria (germs) in our mouths convert sugar in food and drink that we consume into acid which damages teeth.

Bacteria live in dental plaque - a sticky film which builds up naturally on our teeth. Dental plaque contains many types of bacteria but only a small number of these cause dental decay. The main type of bacteria which causes dental caries is Mutans streptococci. Studies have shown that individuals with higher levels of Mutans streptococci are at a greater risk of cavities.

Recent research has shown that babies are not born with decay-causing bacteria. Any time after birth bacteria can be passed on from other people, especially mothers and other close caregivers. Once these bacteria are transmitted to a babies mouth, especially after the first teeth come through, they multiply and become established within dental plaque.

Bacteria can enter the baby's mouth by kissing, sharing food utensils, toothbrushes or other habits that transmit saliva.

If parents and other caregivers have cavities and poor oral hygiene they will have higher levels of decay-causing bacteria which can be passed onto their child.

The risk of a child developing cavities will be less if they are not infected with decay-causing bacteria at an early age.

Children can also "catch" bacteria from other children by sharing food and toys, but they are more likely to receive bacteria from their mother and other close relatives before this happens.

What can be done to reduce the risk?

Parents and caregivers can reduce the risk of passing on decay-causing bacteria from their own mouths by:

• cleaning their own teeth well, to reduce the amount of plaque (which contains bacteria)  in their mouths
• avoiding sugary snacks and drinks between meals which can lead to decay 
• visiting the dentist regularly for check-up and getting any cavities filled 
• avoiding sharing items such as food, spoons, cups and toothbrushes with their baby
• kissing the baby on their cheek, rather than the mouth