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 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.
In the nineteenth century, progressive medical surgeons begged peers to wash their hands so as 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 mouth bacteria.
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 dental 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.1 Most people imagine a genetic link or something in mother’s milk that passes on dental disease. The truth is that dental disease is transferred directly to a child’s new tooth, often during a loving cuddle or a kiss.
Most often, parents and caregivers share their mouth germs with their children (vertical transmission),2 but it is also possible for mouth germs to spread between siblings or from spouse to spouse (horizontal transmission).3 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.4
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.5 The fact is that once a particular kind of bacteria reaches a baby’s first tooth, this bacteria will then colonize 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.6 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—as you will see later on. To give children the best advantage, make sure that healthy bacteria are established in their mouths before the molar teeth erupt. This simple change 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 twenty 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 dental 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.7
From a parent’s point of view, it is important to know that the earlier a child is infected with harmful mouth bacteria, the greater the child’s risk for having cavities later in life. As mentioned earlier, changing the kind of bacteria in your mouth becomes more difficult when molar grooves have become reservoirs of mouth bacteria.8 Baby molar teeth erupt during the second year of life. Consistent with this fact are the results of studies showing that children who are infected with harmful bacteria by age two have the most cavities at age four.9 When parents have healthy mouths during the first year of their baby’s life, their children will have less chance of infection from harmful bacteria and a better chance for oral health. Studies have also shown that at five years of age, children from parents with healthy mouths have 70 to 80 percent less chance of developing cavities, and the benefits may last into adulthood.
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 have 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.
For many years, dental associations in Europe and Scandinavia have been promoting such control of infant mouth bacteria as a means of improving oral health. Recently, a few state health organizations in the United States have begun to educate health professionals about oral bacteria transmission. Unfortunately, some of their recommendations seem unrealistic.
In 2007, for instance, the New York State Department of Health published a guide for oral care during pregnancy and early childhood.11 The department’s advice for preventing harmful bacterial contamination between mothers and infants and between siblings is that families should avoid saliva-sharing activities. Basically, they recommend that a mother not kiss her baby and that children not be allowed to share their toys. As a mother of five, I look at these recommendations and shake my head, wondering how anyone could even think of suggesting that a mother not kiss or share meals with her baby, or how anyone could recommend that toddlers not be allowed to play with one another’s toys.
Even if a mother avoids kissing her baby, inevitably someone else will infect the child. Most parents would prefer to take ownership of this duty and prepare to pass healthy bacteria from their own mouths to their child. In daycare centers there are risks of contamination among children and also from caretakers. A study from a daycare center in Brazil suggests that horizontal transmission occurred among children in such situations.12 Parents should understand these risks if their infant is in daycare and take some simple steps (as outlined in chapter 14) to keep their baby’s teeth healthy and safe.
Mouth chemistry is affected by hormonal factors, poor diet, dehydration, and medications, especially those that change hormone levels, affect diuretic or liquid balance, or have the side effect of dry mouth. Sometimes changes in saliva flow and mouth chemistry occur so slowly that you can be unaware of your increased risk for cavities until problems arise.
Women’s mouth chemistry in particular is volatile, and changes that make the mouth more acidic will have devastating effects on their teeth. A number of life situations can influence and cause the chemistry of the mouth to deteriorate. For example, new mothers who have enjoyed perfect teeth all their lives may be shocked to find cavities develop during their pregnancy. Sometimes the damage is seen as loose fillings, bleeding gums, or sensitive teeth. Hormones trigger a change in a pregnant woman’s saliva, altering its quality and limiting its ability to provide natural tooth protection. These changes can occur at any time during a pregnancy, but the most risk for acidic damage to teeth occurs during the last trimester. (See chapter 13 for more details about changes in a woman’s mouth chemistry during pregnancy.)
Other situations, many beyond your control, can suddenly increase your risk of dental damage without warning. One of the best ways to minimize the chance of cavities is to strengthen your teeth in advance of any problems and to protect teeth daily as much as possible. The following is a list of circumstances that can change your mouth chemistry by making saliva more acidic or by drying the mouth and, consequently, elevating the risk of developing cavities and other dental problems:
Nasal congestion from seasonal allergies, asthma, or sinus infections
Hormonal changes (including pregnancy, adolescence, and menopause)
Medications (including Ritalin)
Illness with fever or nasal congestion (even a simple cold or the flu)
Mouth breathing (athletics, wearing dental braces)
A chronic or acutely stressful situation, such as a death or crisis in the family, or business stress
Duties that involve constant talking, such as lecturing, teaching, or stage performance
Gastric acid reflux
Chemotherapy or long-term illness
Poor diet, with lack of minerals and vitamins
Work in situations where oxygen changes (divers, astronauts)
A feeding or breathing tube in hospitalized patients
The idea of controlling mouth acidity may sound daunting at this time, but you will soon discover how simple routines can give teeth the protection necessary for dental health. Balancing mouth chemistry is relatively easy and will help you avoid dental problems.