Infant Feeding Practices and Dental Caries*

Based on extensive epidemiological and laboratory studies demonstrating the benefits of breastfeeding, the World Health Organisation (WHO) recommends exclusive breastfeeding for infants in the first six months of life. In addition, the guidelines recommend that breastfeeding should continue until two years and beyond supplemented with nutritionally adequate and safe complementary foods to meet evolving nutritional requirements. Importantly, current guidelines do not recommend a time to cease breastfeeding or provide any information about patterns of feeding or discuss the association between infant feeding and dental caries.

Breastfeeding has been shown to reduce the incidence and/or severity of infectious diseases and improve a range of other health outcomes, with benefits even extending into adulthood. Lower rates of otitis media (middle ear infections) and sudden infant death syndrome have been reported in children who are breastfed. Research from the United States reveals that post neonatal mortality is 21% lower among breastfed infants. A range of benefits have also been described for mothers who breastfeed. Finally, improved maternal and child health outcomes lead to a range of benefits for families and the wider community, such as reduced healthcare costs.

Early childhood caries (ECC) is the presence of one or more decayed, missing or filled tooth surfaces in a child under the age of six. It is associated with increased caries risk in the permanent dentition, increased number of hospitalisations and emergency visits, increased treatment costs, delayed growth and development, loss of school days, diminished ability to learn and reduced oral health related quality of life. ECC is a significant problem affecting Australian children, with severity increasing as socioeconomic statuses decreases. The role of infant feeding practices, including breastfeeding, bottle feeding and the use of infant formula in ECC is not fully understood but needs to be considered carefully when providing dietary advice to patients.

There is limited evidence for an association between dental caries and breastfeeding, mostly due to poor study design. However, there is moderate to weak evidence that prolonged, nocturnal and on-demand feeding is associated with ECC. In a recent Japanese study, the prevalence of ECC was significantly higher amongst children who were breastfed beyond 18 months of age, compared to those who stopped breastfeeding at six months. The authors suggest that a decline in maternal protective elements such as immunoglobulins and minerals such as calcium and phosphate in breast milk with prolonged breastfeeding may reduce its benefits and therefore increase potential for dental caries. In discussions with parents, clinicians should bear in mind the clear benefits of breastfeeding and the multi-factorial nature of dental caries. As such, recommendations against on-demand feeding after eruption of the first primary tooth should be complemented with broader dietary advice regarding reducing other sources of sugar-containing foods and drinks and appropriate oral hygiene practices.

There is evidence that prolonged bottle feeding with bovine milk and added sucrose results in pooling of milk on the tooth surface, which can lead to early establishment of Streptococcus mutans in the oral cavity. There is debate as to whether there is a clear link between prolonged bottle feeding and early childhood caries. However, what is clear is that feeding at night is a major risk factor. Parents should be counselled regarding the risks of nocturnal feeding, and bottles during the night (apart from those containing plain water) should be discouraged. It has been established that parents need significant amounts of support to change behaviours; they may need to be referred to an appropriate service to help with bedtime routines and to be provided with strategies other than nocturnal feeding to help placate their child.

Numerous in vivo and in vitro studies have demonstrated the ability of both bovine milk and soy-based infant formula to cause a significant decrease in pH and demineralisation of primary teeth, an effect that is further exacerbated with the addition of sucrose or fermentable carbohydrate. Infant formula has been reported to be more cariogenic than bovine and breast milk. Given the cariogenicity of infant formula, clinicians should recommend against night time and frequent feeding of infant formula, particularly in a nursing bottle. In the past, the use of infant formula has also been linked to increased fluorosis amongst young children, in both fluoridated and non-fluoridated communities. However reduction in the level of fluoride in formula powders by manufacturers in the early 1990s has allayed concerns regarding fluorosis. Recent evidence indicated that there is no difference in fluorosis among formula users in a fluoridated community but that the use of non-fluoridated water in mixing infant formula may be associated with increased caries risk. The National Health and Medical Research Council (NHMRC) recommends the use of cooled, boiled tap water to prepare infant formula.

When approaching discussions regarding possible dental implications of feeding practices it must be remembered the ways that parents choose to feed their infants can be a very personal choice. Families may have complex social and emotional reasons for the feeding practices they utilise in their home. While as oral health professionals we can counsel families regarding the implications of certain feeding practices, we must remember that decisions come down to the parents and families involved.

*By K Bach and MJ Silva

Paediatric Dentistry Program

Melbourne Dental School

University of Melbourne

On behalf of the Oral Health Committee, Australian Dental Association.