It's normal and common for children to breastfeed to sleep. However, many parents are told that breastfeeding to sleep may affect dental health. Is this something to be concerned about?

Breastfeeding is important

The value of breastfeeding for maternal and child health is significant and widely accepted (Victora et al 2016). The World Health Organization recommends children be breastfed for the first 2 years of life and beyond.

What does the research say?

Two recent systematic reviews of breastfeeding and tooth decay (Tham et al 2015 & Cui et al 2017) found that breastfeeding up to 12 months protects against tooth decay. However, they also found an increased risk of tooth decay when breastfeeding continued beyond 12 months. It was noted that these results did not take into account socioeconomic status and intake of sugary foods/drinks. These factors are known to increase the risk of tooth decay, so are more likely to influence this risk than breastfeeding.

A more recent study (Denenish et al 2020) found that the risk of tooth decay was not linked to breastfeeding beyond 12 months. However, what this study did find was that the only factors associated with tooth decay were high intake of sugary foods/drinks and low socioeconomic status.

Another recent study (Ha et al 2019) found no significant association between tooth decay and breastfeeding beyond 24 months in children living in areas of fluoridated drinking water. This suggests that early life access to drinking water containing fluoride is an important factor in reducing the risk of tooth decay.

Could breastmilk protect against tooth decay?

Some research suggests that breastfeeding may actually protect against tooth decay, while formula may play a role in its development.

Antibodies in breastmilk may help to reduce the growth of bacteria (including Streptococcus mutans, the bacterium that causes tooth decay). Lactoferrin, a protein in breastmilk, actually kills S. mutans (Brams et al 1983 & Gardner et al 1977). Rugg-Gunn et al (1985) reported that S. mutans may not be able to use lactose, the sugar found in breastmilk, as easily as sucrose that is found in some formulas.

Erickson et al (1999) showed that some formulas dissolve tooth enamel, significantly reduce pH (make it acidic), support the growth of bacteria and can lead to tooth decay. Ribeiro & Ribeiro’s (2004) review concluded that formula has the potential to cause tooth decay.

Breastfeeding is different to bottle-feeding

There is a vast difference between sucking on a bottle and sucking on the breast. In bottle-feeding the milk is released into the front of the mouth and pools around the teeth. A breastfeeding baby draws the nipple into their mouth and the milk is released into the throat. This causes the baby to swallow. When a baby falls asleep with a bottle, the teat keeps on slowly leaking any milk left in the bottle, into the baby’s mouth. The breast does not release milk unless actively sucked.

Did our ancestors suffer tooth decay?

Archaeological studies of the teeth of children in prehistoric times show that there was very little decay. It can be assumed that those who survived babyhood would have been breastfed for long periods and probably would have slept with their mothers and breastfed during the night (Erickson et al 1999 & Palmer 1998).

Factors which contribute to tooth decay

Factors other than how a baby feeds may also affect the chances of tooth decay. For example:

Sugar intake. Frequent exposure to sugar-laden food and drink (Ribeiro & Ribeiro 2004). Limiting your child’s intake of foods and drinks high in free sugars is important as is having fluoridated tap water as your family’s main drink.

Streptococcus mutans entering a baby’s mouth. Parents, caregivers, siblings, friends and others can transmit this decay-causing bacterium to the baby without knowing it (Berkowitz 1996). This can happen by kissing on the mouth, sharing a toothbrush, drink or spoon with them, or by sucking on their dummy, thinking that this cleans it before putting it back into the child’s mouth. Running it under a tap would be a safer option.

Lack of saliva. Saliva reduces the risk of tooth decay because it helps to wash sugars from the teeth and also buffers against acids (reduces the acidity). Saliva flow naturally reduces during sleep (Bowen 1998). Saliva flow is also reduced in asthma, prematurity, diabetes and when using certain medications such as beta 2 agonists (used to treat asthma), antihistamines, benzodiazepines (‘sleeping pills’) and drugs taken for nausea and vomiting (Ribeiro & Ribeiro 2004 & Palmer 2000).

Maternal or foetal illness or stress during pregnancy (Ribeiro & Ribeiro 2004 & Palmer 2000).

Maternal smoking during pregnancy (Iida et al 2007) .

Poor dietary habits of the family (Ribeiro & Ribeiro 2004 & Palmer 2000).

Poor oral and overall hygiene of the family (Ribeiro & Ribeiro 2004 & Palmer 2000). Regardless of how your baby is fed, it is important to clean their teeth properly once the teeth appear and to have regular dental check-ups.

Family genetics. In some cases there are enamel defects (Ribeiro & Ribeiro 2004).

Other conditions. These include low birth-weight (including prematurity), malnutrition, asthma, recurrent infections and chronic diseases (Ribeiro & Ribeiro 2004).

Conclusion

As breastfeeding is so important for maternal and child health, it is important to support breastfeeding (including breastfeeding to sleep, which is normal and common) for as long as a mother and child desire. At the same time, it is also important to minimise the risk of tooth decay with measures such as proper teeth cleaning, regular dental check-ups, drinking fluoridated water and avoiding sugary foods and drinks.

References

Berkowitz R 1996, Etiology of nursing caries: a microbiologic perspective. Public Health Dent 56:51–54. Bowen WH 1998, Response to Seow: biological mechanisms of early childhood caries. Community Dent Oral Epidemiol 26(1 Suppl):28–31. Cui L, Li X, Tian Y, et al 2017, Breastfeeding and early childhood caries: a meta-analysis of observational studies. Asia Pac J Clin Nutr 26(5):867–880. Devenish G, Mukhtar A, Begley A, Spencer AJ, Thomson WM, Ha D, Do L, Scott JA 2020, Early childhood feeding practices and dental caries among Australian preschoolers. Am J Clin Nutr 111(4):821–828. Erickson PR, McClintock KL, Green N, et al 1998, Estimation of the caries-related risk associated with infant formulas. Pediatr Dent 20:395–403. Erickson PR, Mazhari E 1999, Investigation of the role of human breast milk in caries development. Pediatr Dent 21:86–90. Ha DH, Spencer AJ, Peres KG, Rugg-Gunn AJ, Scott JA, Do LG 2019, Fluoridated Water Modifies the Effect of Breastfeeding on Dental Caries. J Dent Res 98(7):755–762. Iida H, Auinger P, Billings RJ, Weitzman M 2007, Association between infant breastfeeding and early childhood caries in the United States. Pediatrics 1(120):e944 -e952. Palmer B 1998, The influence of breastfeeding on the development of the oral cavity: a commentary. J Hum Lact 14:93–98. Palmer B 2000, Breastfeeding and infant caries: no connection. ABM News and Views, The Newsletter of The Academy of Breastfeeding Medicine 6(4):27 & 31. Ribeiro NM, Ribeiro MA 2004, Breastfeeding and early childhood caries: a critical review. Jornal de Pediatria 80(5 Suppl):S199–S210. Rugg-Gunn A, Roberts GJ, Wright WG 1985, Effect of human milk on plaque pH in situ and enamel dissolution in vitro compared with bovine milk, lactose, and sucrose. Caries Res 19:327–334. Tham R, Bowatte G, Dharmage SC, et al 2015, Breastfeeding and the risk of dental caries: a systematic review and meta-analysis. Acta Paediatr 104(467):62–84. Victora CG, Bahl R, Barros AJ, et al 2016. Breastfeeding in the 21st century: epidemiology, mechanisms, and lifelong effect. Lancet 387(10017):475–490.

The information on this website does not replace advice from your health care providers.

© Australian Breastfeeding Association May 2020