IN the 19th century, progressive medical surgeons begged peers to wash their hands thoroughly in order to prevent the spread of infection. Today, I beg patients to clean their mouths and their toothbrushes to control the spread of tooth and gum disease between family members. Today we have become more aware of the delicate balance that exists between the bacteria that help and protect us and the bacteria that cause infection. Overuse of antibiotics showed us that if protective bacteria were removed, overgrowth by harmful ones often followed, and the same reactions can be seen when we look at oral bacteria.

Surprising as it may seem, many people are unaware that dental disease is just like any other infection caused by bacteria. It is a disease that can be spread easily, is transferred from person to person, and worst of all can grow on things like toothbrushes. Once you realize that dental disease is this kind of infection, you understand how very simple steps can be used to control it.

Bacteria that live on teeth can grow only when attached to a hard, non-shedding surface. Some kinds of tooth bacteria are harmful, whereas others are good for our health. In fact, it appears that teeth need a barrier of healthy protective bacteria to stop harmful ones from damaging the tooth surface. The balance between good and bad bacteria is important for dental health, and it is also important to know that this balance can change. People are often surprised to learn that they can lose healthy bacteria following an abrasive dental cleaning, after taking a course of antibiotics, or when the mouth becomes dry or acidic for long periods of time. During times of change, it is possible for a new type of bacteria to infect your mouth and suddenly cause damage to your teeth and dental health.

Tooth bacteria rarely exist in a baby’s mouth before the presence of a tooth. Therefore, the origin of these bacteria is necessarily someone else’s tooth. DNA studies have illustrated that a parent, usually the mother, is most often the person who passes tooth bacteria from her mouth to the baby’s mouth when his or her first tooth erupts. Most people imagine a genetic link or something in the mother’s milk that passes on dental disease. The truth is that the dental disease is transferred directly to a child’s new tooth, often during a loving cuddle or kiss.

Most often, parents and caregivers share their mouth germs with their children (vertical transmission), but it is also possible for mouth germs to spread between siblings or from spouse to spouse (horizontal transmission). Parents should also be aware that children born by caesarean section appear to be infected by mouth germs earlier – possibly because they lack some kind of protection – than do vaginally delivered infants.

Bacteria travel to the new baby tooth most often in a droplet of saliva. The bacteria can transfer during a kiss, from a drop of saliva on spoons or pacifiers, or from food shared with a baby. I would never, suggest that parents stop kissing their baby or worry about sharing food. Think about this: If the bacteria do not come from your mouth, they will be transferred from the mouth of someone else who comes into contact with your child. Since this bacteria transfer cannot be stopped, it makes more sense to control the kind of bacteria passed to children.

Obviously, you want a baby to be infected with healthy, dentally, protective bacteria rather than aggressive, cavity-forming ones. The fact is, that once a particular kind of bacteria reaches a baby’s first tooth, this bacteria will then colonise or spread to the other baby teeth as they erupt. It has also been shown that whenever there are many harmful bacteria in a parent’s mouth, the chances that they will transfer to the child are greater. It has also been shown that the first kind of bacteria to infect the biting surfaces of molar teeth,

usually become the dominant strain in the mouth because the grooves of these teeth become reservoirs of bacteria for the mouth. Changing the kind of bacteria in a child’s mouth after molar teeth have erupted becomes more difficult. This fact can also be used to a parent’s advantage. To give children the best advantage, make sure that health bacteria are established in their mouths before the molar teeth erupt. This simple charge can provide your child with many years of dental protection.

Research during the 1980s illustrated how bacteria were transferred between family members and from mouth to mouth. A simple and successful method of controlling this transmission was found just a few years later. For 20 years we have known how to reduce both the inheritance of bad tooth bacteria, and the chance of a parent infecting their child with the bacteria that cause cavities. Parents with bad teeth can get rid of aggressive and harmful bacteria from their mouths, and even without traditional treatment. You may be shocked to discover that it is possible to remove harmful bacteria even if you still have cavities or cannot go to the dentist, for whatever reason. When the bad bacteria are gone from your mouth, protective ones will take their place.

Preventing the passage of harmful germs to the next generation may be the most promising method of preventing cavities in children’s teeth. If this is the first time you heard about this kind of bacterial transfer, it will be natural for you to wonder why there has been no media attention and no national education on the topic.