Carbohydrates in Baby Bottles Increase Risk of Tooth Decay

Babies are at higher risk for mutans streptococci (MS) colonization (a risk factor for early childhood caries) if their mothers have dense salivary MS reservoirs¹ because mothers and their babies often share saliva (kiss babies on lips, taste food destined for babies, etc.). The purpose of this study was to determine if MS colonization in an infant increases with the use of a nursing bottle containing carbohydrates. Sixty Puerto Rican infants (mean age of 15 months, range 12–18 months) were studied. All were healthy, had 4 caries-free maxillary anterior primary teeth and slept with a bottle that contained carbohydrates. There was no control group. Two pooled plaque and saliva samples were obtained from each infant in order to isolate MS colonies. The bacteria were counted and the density of MS determined. Fifty-one of the 60 subjects (85%) harbored MS in at least one of the two samples. Earlier studies^1,2 have shown that mothers with dense salivary MS had babies at greater risk for MS colonization when compared to mothers with negligible salivary MS (P=.01). Seventy-eight percent of the infants younger than 15 months and 100% of the infants older than 16 months had detectable MS. The density of the infection did not vary with age for plaque or saliva samples. These results confirm earlier animal studies that colonization of MS is enhanced by the addition of carbohydrates to nursing bottles when compared to a bottle containing only water.

This study adds to the mounting evidence that the use of sweetened beverages in the nursing bottle puts a child at greater risk for early childhood caries by increasing the frequency and duration of exposure of the teeth to carbohydrates when compared to no bottle or a bottle with just water. Dental caries is a multifactorial, infectious disease that is completely preventable in healthy children with well-formed teeth. The first step in the development of dental caries is colonization of the oral cavity with MS. Earlier studies have shown that age 18 to 34 months is a discrete “window of infectivity” during which infants acquire MS.² A more recent study has shown MS colonization of predentate infants.³ The second step is the accumulation of these organisms to a pathogenic level as a result of the exposure to frequent carbohydrate substrates and poor oral hygiene. The final outcome, in most cases, is the demineralization of enamel and the formation of cavitated lesions.⁴ 

The step at which intervention can be most effective is step two. The presence of MS is required for the caries process and high levels of MS are more frequently associated with caries than lower levels of MS. The pathophysiology of this process is as follows: MS metabolizes carbohydrates with the resultant production of acid; MS thrives in an acidic environment and, therefore, as the...