Abstract: According to the WHO, “breastfeeding is the normal way of providing young infants with the nutrients they need for healthy growth and development. Exclusive breastfeeding is recommended up to 6 months of age, with continued breastfeeding along with appropriate complementary foods up to two years of age or beyond”.
However, several studies have reported prolonged and unrestricted breastfeeding as a potential risk factor for primary tooth caries (ECC).
On-demand breastfeeding, particularly while lying down at night, would seem to cause ECC because milk remains in the baby’s mouth for long periods of time.
There is lack of evidence that human milk is cariogenic; other factors, such as oral hygiene, may be more influential in caries development than on-demand breastfeeding. Moreover the biomechanics of breastfeeding differs from those of bottle feeding and milk is expressed into the soft palate and swallowed without remaining on teeth.
Indeed we cannot forget that the main factor influencing caries development in infants is the presence of bacteria streptococcus mutans that thrives in a combination of sugars, small amounts of saliva and a low pH.
Today the question is open and recently Chaffee, Felines, Vitolo et al.  have found that breastfeeding for 24 months or longer increases the prevalence of severe early childhood caries in low-income families in Porto Alegre, Brazil. These results do not claim that prolonged breastfeeding is the cause of tooth decay; we can expect an association with food for infants often rich in refined sugars, which cause the reduction of the protective effect of saliva on the deciduous teeth enamel.
In Japan, Kato, Yorifuji, Yamakawa et al.  have found that infants who had been breastfed for at least 6 or 7 months, both exclusively and partially, were at elevated risk of dental caries at the age of 30 months compared with those who had been exclusively fed with formula. The authors themselves say, however, that further studies with more elaborate methods of assessment of breastfeeding may be necessary to determine the cariogenic nature of breastfeeding.
In the meantime, given the many benefits of breastfeeding, the practice should continue to be strongly encouraged. Dental professionals should encourage parents to start proper oral hygiene with their children as soon as the first tooth erupts, and they should keep the intake of sugary beverages to a minimum.
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