Avoiding Dental Caries

Joylyn Fowler
Garden Grove CA USA
From NEW BEGINNINGS, Vol. 19 No. 5, September-October 2002, p. 164-167

Web editor's note: See also the companion article from the same issue, "Other Experiences with Dental Caries."

Zachary was almost two when his mother, Elizabeth, noticed a brown spot on one of his molars. After trying to brush what she thought was a bit of food away, she realized that the spot was not food and took Zachary to the dentist.

Zachary was not interested in an examination and it wasn't until he was under anesthesia that the dentist realized that all but one of his teeth had decay. Zachary's four front teeth were pulled, two were capped, and the rest of his teeth, save his one tooth without decay, were filled. The dentist told Elizabeth that breastfeeding at night was the same as bottle-feeding at night, and that she needed to stop breastfeeding at night. Elizabeth didn't believe that breastfeeding caused Zachary's cavities. "I told the dentist that people had been nursing for millennia without having problems like this, so it can't be breastfeeding," she said.

Elizabeth chose to continue breastfeeding at night because her family was getting ready to move and it was a stressful time. She tried to clean Zachary's teeth by wiping them with a soft cloth after each nursing. However, cleaning his teeth often woke him up, so it didn't work very well at night. After a few months, Elizabeth gently weaned Zachary at night.

Why did Zachary's dentist believe that breastfeeding, especially at night, can contribute to cavities (dental caries)? Human milk contains sugar in the form of lactose. It is well known that foods containing sugar can contribute to cavities. Some research has shown a relationship between breastfeeding and caries, while other research shows no link. In the US, the American Academy of Pediatric Dentistry recommends that nighttime breastfeeding should be avoided after the first primary tooth emerges (Pediatric Dentistry 2001-2002). Many dentists agree with this recommendation, both in the US and elsewhere. Let's take a look at why the research is inconsistent.

Examining the Research

Dr. Joyce Sinton and her colleagues did a comparison of research on feeding methods and dental caries in an attempt to discover why studies disagree about whether breastfeeding contributes to dental caries. Overall, their comparison indicated that many of the studies that showed a link between breastfeeding and caries had contradictory findings and weak methodology. Most of the articles found by the researchers were not included in the final comparison because they were simply "case studies." This means that they were descriptions of one or more breastfed children who were observed after cavities had already been identified. These studies assumed that the decay was caused by breastfeeding, but offered no proof. The researchers stated that excluding these studies resulted in excluding most of the "classical" articles on the subject.

The remaining studies were carefully compared. One possible source of conflicting results is that the studies often didn't consider other potential factors in dental caries, such as the fluoridation of water supply or the child's diet other than breastfeeding. The studies also used imprecise definitions for both "breastfeeding" and for the effectiveness of parents' dental health practices. For example, babies who were both breastfed and fed formula on a regular basis might be considered breastfed in one study and formula-fed in another study. Confusion about such definitions often gives misleading research results, since exclusive breastfeeding leads to different results than mixed feeding. It's just plain bad science to use such imprecise definitions.

Finding accurate information about breastfeeding and dental caries is important because early childhood caries are both very common and very expensive to treat. Some researchers assert that early childhood caries are almost epidemic in some populations (Tinanoff and O'Sullivan 1997). Costs per case have been estimated at $700 to $1200 (US) for the dental treatment and $200 to $1500 (US) for medication (Erickson 1999). The costs in stress and trauma for both parents and child are not so easily measured, particularly when there is a sudden weaning involved.

Evidence Supporting Breastfeeding

Not all dentists or researchers believe that breastfeeding, even breastfeeding at night, contributes to dental caries. According to a study led by Dr. Harold Slavkin, DDS, "Population-based studies do not support a definitive link between prolonged breastfeeding and caries." Dr. Constantine Oulis and colleagues concluded that breastfeeding may "act preventively and inhibit the development of nursing caries in children." Dr. Harry Torney looked at 107 children who had breastfed at least two years (about half were still nursing at the time of the study). His results indicated there is no evidence to support the view that prolonged, on-demand breastfeeding is likely to lead to dental caries (Torney 1992).

Dr. Brian Palmer, DDS, is one of the most outspoken and well-known defenders of breastfeeding as it relates to dental caries. He believes that early childhood caries are a relatively new phenomenon. Palmer has examined the skulls of prehistoric to early historic infants and children in various museums. Less than 1.4 percent of teeth that were examined had decay. Of 1,344 deciduous teeth examined, only 19 had any signs of decay, and of those 19, only four (0.3 percent) had significant decay. Anthropologists say that anatomically modern humans have been around about 100,000 years, with modern humans being present for about 30,000 years. However, according to skull studies, early childhood caries have been around for only about 8,000 to 10,000 years, which suggests that babies and toddlers remained free of decay for about 92,000 years (Palmer 2000).

What happened to cause young children to begin getting cavities? Humans started cultivating their own food and diets changed. Presumably, prehistoric babies were breastfed, most likely all night long and possibly until they were toddlers or older. It seems improbable that human milk would cause decay-if it did, there would be decay evident in skulls older than 10,000 years. And, as Dr. Palmer suggests, it would be "evolutionary suicide for human milk to cause decay."

More information comes from two different studies in which researchers compared the effects of modern-day artificial baby milk (formula) and human milk on some factors believed to contribute to dental caries. Their studies showed vital differences between human milk and most formulas. First, they found that human milk does not significantly lower the pH in the mouth, while almost all brands of artificial baby milk did. The bacteria that is thought to significantly contribute to decay, Streptococcus mutans (S. mutans) thrives in a low pH. Second, most formulas supported significant bacterial growth, while human milk supported only moderate bacterial growth. Third, formulas were found to dissolve tooth enamel (the outer layer of teeth), while human milk actually deposited calcium and phosphorus into enamel (a process known as remineralization). Researchers also concluded that human milk is not cariogenic (does not cause cavities) unless another source of carbohydrates is available for bacteria to feed on. Most artificial baby milk formulas tested were cariogenic (Erickson 1999).

These studies provide an example of why clear definitions of terms are important in research. Since formula was shown to dissolve enamel while breastfeeding remineralizes enamel, a baby who receives mixed feedings could be expected to show mixed results in any research on early childhood caries.

S. Mutans

Babies and toddlers are most often infected with the S. mutans bacteria by a parent or other caretaker. This can happen in a variety of ways. Parents may let curious babies chew on toothbrushes. The bacteria may be passed on through kissing or using the same eating utensils. Once the S. mutans is in the child's mouth, it can multiply quickly. It has properties that prevent the growth of other similar bacteria and many other microorganisms, so it may become the most common organism in the child's mouth (Slavkin 1999).

Preventive measures may help combat S. mutans in babies and toddlers. One study shows: "When pregnant women in their seventh month rinsed their mouths daily with sodium fluoride and chlorhexidine, bacterial colonization in their children's mouths was delayed by an average of four months" (Slavkin 1999). However, both fluoride and chlorhexidine must be prescribed and have side effects. Their use is controversial. A mother should consult with her personal health care provider to discuss the risks versus the benefits before deciding to use them.

Delay in exposure to S. mutans is one key to fighting early childhood caries. Not sharing eating utensils and toothbrushes is another. If babies use artificial nipples, including pacifiers, the parent or caretaker should never put them in his or her own mouth. Because S. mutans thrives in a low pH environment, keeping the mouth at a higher pH level is one way of preventing S. mutans from taking over the microbial ecosystem of the mouth (Slavkin 1999). As previously stated, formula lowers pH in the mouth and human milk does not, thus supplementation with formula should be avoided and if given, parents should clean the teeth afterward.

Levels of pH are normally reduced during the process of digestion, gradually rising as food leaves the mouth. When we eat or drink, saliva begins the process of breaking down the food into sugar. These sugars bathe the teeth, and bacteria feed on them, thereby lowering the pH level in the mouth. All foods contain sugar, and bacteria in the mouth feed on the sugar. When the level of pH in the mouth is reduced, mineral ions from the enamel surfaces are removed. Between meals, saliva acts to restore normal pH. As stated previously, human milk appears to remineralize enamel. Since human milk adds calcium and phosphorus to (remineralizes) the teeth and does not lower pH levels, it appears to make children's teeth stronger and help prevent cavities.

Dr. Palmer points out that:

Several components of human milk may also protect against the development of caries. IgA and IgG have the potential to retard streptococcal growth; Streptococcus mutans is highly susceptible to the bactericidal action of lactoferrin, a major component of human milk.

Several components of human milk may also protect against the development of caries. IgA and IgG have the potential to retard streptococcal growth; Streptococcus mutans is highly susceptible to the bactericidal action of lactoferrin, a major component of human milk.

How Milk is Delivered

The mechanics of breastfeeding make it unlikely for human milk to stay in the baby's mouth for long. During breastfeeding, the nipple is drawn deep within the baby's mouth, and milk is literally squirted into the back of his mouth. The suckling process includes a swallow and the nursing child must swallow before he can go on to the next step. In contrast, baby bottles can drip milk, juice, or formula into the baby's mouth even if he is not actively sucking. If the baby does not swallow, the liquid can pool in the front of the mouth around the teeth. The artificial nipple is very short, so the liquid in the bottle is likely to pass over teeth before being swallowed.

Dry mouth is another factor that can increase the incidence of early childhood caries. Saliva, which helps maintain normal pH, is not produced as much at night, especially among those who breathe through their mouths. This is one reason why brushing the teeth before going to sleep helps prevent dental caries. An infant or toddler who nurses often at night continues to produce saliva, which may help combat dry mouth.

Family Matters

Another factor of dental caries is genetics. A child's genes cannot be changed, however it is important for parents to consider whether or not cavities and dental issues are common in their families. By recognizing this factor, they can ensure that they do everything possible, from pregnancy on, to help prevent early childhood caries in their own children.

Good oral hygiene habits can go a long way in preventing early childhood caries. Parents who brush regularly not only set a good example for their children, but they help to reduce the amount of bacteria in their own mouths, thus reducing the chance that they will pass the S. mutans bacteria to their children. Parents can take their children with them to the dentist from the time they are infants, and by doing so, they will familiarize their children with the dentist and with what happens in a dental office. In families with a genetic predisposition toward dental caries, children should be seen by a dentist starting with the eruption of the first tooth and thereafter every six months. Early dental visits can also diagnose any enamel defects.

Parents should begin cleaning an infant's teeth once they erupt. Parents can clean a baby's gums and teeth with a piece of gauze or a soft washcloth. Children should learn to brush their teeth early, using a soft toothbrush, but parents should still do a thorough brushing at least twice a day, as children are not efficient at brushing their own teeth until they are older.

An excellent diet goes a long way toward preventing caries. Children who eat nutritious foods are in better health and therefore better able to resist bacteria. Offer your child water instead of juice or other liquids because it does not reduce pH or coat the teeth in sugar.

Foods that stay in the mouth a long time or stick to the teeth should be occasional treats only. For example, a piece of hard candy is consumed by a child over a long period of time. During that time, the pH level in the child's mouth drops. The sugar coats the teeth and is consumed by bacteria. Demineralization starts, and until the child brushes, or enough saliva washes away the sugar and reestablishes the proper pH, the teeth are at risk. Eating an apple requires chewing and swallowing, which encourages saliva to wash the sugar off the teeth. However, even healthy snacks, such as dried fruit, can stick to teeth and cause the demineralization process to start.

According to Dr. Palmer, genetics is not the only factor to consider in preventing caries. There are also things that parents can do to help prevent caries before their baby is even born. Four factors that can contribute to a higher rate of dental caries, as described by Palmer, include maternal stress, especially bereavement stress; a reduced intake of dairy products; a medically diagnosed illness in the mother; and antibiotics taken by the mother during pregnancy.

Obviously, some of these things can be beyond a mother's control. Illness happens, as does death; however, reducing stress can have positive effects for both mother and baby. Good prenatal care can contribute to better nutrition and fewer illnesses. When illness does occur, antibiotics may sometimes be prescribed during pregnancy. Each woman should consider her situation and discuss the risks of antibiotics versus the benefits with her health care provider. Avoiding these risk factors entirely may not be possible, but mothers can be aware of them and do the best they can.

Treatments

Parents need to choose a treatment plan that they feel is best for their child. This issue of NEW BEGINNINGS includes examples of options different parents chose. Other examples were printed in the "Toddler Tips" column in the July-August 2000 issue of NEW BEGINNINGS.

Nutritional support and fluoride treatments are options that may help remineralize teeth if decay is caught at an early stage, which is why proactive treatment and early dentist visits are a good idea for those in the high risk category. Brushing the teeth regularly can reduce bacteria levels. A recent article in Mothering magazine states that in "Pioneering efforts to kill S. mutans, researchers have experimented successfully with chemical antibacterial mouthwashes" (Reagan 2002).

Once caries have become serious, there may be no other option except surgery to repair or remove the teeth. If general anesthesia should be considered necessary, parents may wish to learn more about recommendations for pre-operative fasting times for human milk and work with their child's anesthesiologist to make the pre-operative time more gentle for their child.

Parents of breastfed babies may need to search to find a pediatric dentist they can work with. In the absence of a pediatric dentist already well-informed about breastfeeding, parents sometimes work to educate dentists by presenting them with the relevant research on breastfeeding and dental caries.

Conclusions from Key Studies on Dental Caries and Breastfeeding

Was it really necessary for Zachary to wean? According to Dr. Brian Palmer, DDS, the answer is no. Dr. Palmer is not the only one to make that statement:

Population based studies do not support a definitive link between prolonged breastfeeding and caries (Slavkin 1999).
Prolonged demand breastfeeding does not lead to higher caries prevalence (Weerheijm 1998).
Breastfeeding may act preventively and inhibit the development of nursing caries in children (Oulis 1999).

Closing Thoughts

Zachary's mother is not the only parent who was told to stop breastfeeding. Katie, the mother of a nursing toddler, Bethany, was told by a pediatric dentist to stop nursing immediately. Katie found another dentist who had more information regarding early childhood caries and breastfeeding and continues to nurse today, knowing that breastfeeding did not contribute to her daughter's caries, but probably reduced the severity. And most certainly, the fact that Bethany continues to nurse not only comforts her after procedures (such as getting her caries fixed) but also helps in so many other ways.

References

AAP. Breastfeeding and the use of human milk policy statement. Pediatrics 1997; 100(6): 1035-39.
Clinical guideline on baby bottle tooth decay/early childhood caries/ breastfeeding/early childhood caries: unique challenges and treatment in pediatric dentistry. Pediatr Dent 2001-2002: 29-30.
Erickson, P. R. & Mazhari, E. Investigation of the role of human breast milk in caries development. Pediatr Dent 1999; 21(2): 86-90.
Erickson, P., McClintock, K. L., Green, N. et al. Estimation of the caries related risk associated with infant formulas. Pediatr Dent 1998; 20(7): 385-403.
Oulis, C. et al. Feeding practices of Greek children with and without nursing caries. Pediatr Dent 1999; 21(7): 409-16.
Palmer, B. Breastfeeding and infant caries. ABM News and Views 2000 Dec; 6(4): 27-31.
Palmer, B. "Infant Dental Decay-Is it Related to Breastfeeding." A Presentation, 2000.
Reagan, L. Big bad cavities, breastfeeding is not the cause. Mothering 2002 Jul-Aug; 113.
Rugg-Gunn. A. et al. Effect of human milk on plaque pH in situ and enamel dissolution in vitro compared with bovine milk, lactose and sucrose. Caries Res 1985; 19(4): 327-34.
Sinton, J. et al. A systematic overview of the relationship between infant feeding caries and breast-feeding. Ont Dent 1998; 75(9): 23-27.
Slavkin, H. Streptococcus mutans: early childhood caries and new opportunities. JADA 1999; 130:1787-92.
Torney, H. "Prolonged, On-Demand Breastfeeding and Dental Caries-An Investigation" [unpublished MDS thesis]. Dublin, Ireland, 1992.
Tinanoff, N. & O'Sullivan, D. M. Early childhood caries: overview and recent findings. Pediatr Dent 1997; 19(1), 12-16.
Weerheijm, K. L. Prolonged demand breastfeeding and nursing caries. Caries 1998, 32(1): 46-50.

Web site of Interest

www.brianpalmerdds.com

Preventing Caries While Pregnant

Eat well and include adequate calcium in your diet.
Reduce stress levels if possible.
Take care of yourself, get good prenatal care, and treat any illnesses immediately.
Avoid taking antibiotics if possible.

Preventing Caries in Infants

Delay solids until at least six months or longer, until the child shows signs of readiness.
Don't share eating utensils or toothbrushes, and try not to let anything that's been in your mouth get into your baby's mouth.
If your baby uses any artificial nipples, don't put them in your mouth or let anyone else put them into their mouths.
Set an example of good oral hygiene, brushing your own teeth well and often.
Brush your child's teeth as soon as the first tooth erupts, especially after the child consumes anything other than water or human milk.
Provide nutritious food for your family, including lots of whole foods and natural sugars.
When eating treats, think about how long the teeth are bathed in the sugar involved and choose wisely.
Nurse often at night, and provide a glass of water by the bed to decrease dry mouth during the night.

Cause of Dental Caries

Streptococcus mutans, a bacteria that can be passed from parent to child.
High risk factors in pregnancy, including maternal stress, illness, antibiotic use, and poor diet.
Poor family diet.
Poor oral hygiene.
Dry mouth.
Frequent and prolonged exposure to sugar.

Last updated 11/16/06 by jlm.

Page last edited Sun Oct 14 09:30:22 UTC 2007.