to the editor: As I read the excellent article by Sanchez and Childers1 entitled “Anticipatory Guidance in Infant Oral Health: Rationale and Recommendations,” I was struck by two thoughts.
First, although there are studies in the dental literature that would seem to show an association between “prolonged” (more than 12 months' duration) and/or nighttime breast-feeding and the formation of dental caries, most of those studies are poorly controlled for the other cariogenic factors (e.g., high-sugar diet, poor dental hygiene, lack of early or routine dental examinations and positive family history). Other in vitro2 and in vivo studies3 have concluded that human breast milk and breast-feeding are not by themselves a cause of dental caries. Therefore, in view of the many benefits of breast-feeding, it would seem imprudent to recommend a specific age of weaning with respect to this conjectural concern.
Second, although an association between bottle feeding and malocclusion has been suggested, I was surprised that this aspect of dental health was not mentioned. Multiple studies have demonstrated that the shape of the hard palate in children who suck on a relatively harder artificial nipple is markedly different from that in breast-fed children and that this difference in shape contributes to malocclusion.4,5 One study even suggests a “dose-dependent” association, with each additional month of breast-feeding contributing to a decline in malocclusion index.5
The American Academy of Pediatrics was apparently aware of these facts when they formulated their most recent recommendation that children be breast-fed for “at least 12 months, and as long thereafter as mutually desired.”6
in reply: We appreciate the comments of Dr. Saenz because they illustrate a point of confusion and controversy over the issue of breast-feeding and its potential relationship to early childhood caries. The term “prolonged,” as used in our article,1 was intended to be associated with an excessive length of time during feedings rather than being associated with a specific age of weaning. We certainly appreciate the lack of consensus of the proper time for weaning and, although from a dental standpoint many dentists encourage parents to wean children from the bottle, the breast and the “sippy cup,” we can understand and accept the potential benefit of human breast milk for an extended period (more than one year of age).
As Dr. Saenz's letter indicates, there is no clear evidence specifically linking human milk to caries. Although many studies have been conducted, the literature on the caries potential of breast-feeding is not decisive. The Academy of Pediatric Dentistry guidelines2 state that the group “recognizes the need for further scientific research on the oral effects of breast-feeding and the consumption of human milk.” Nonetheless, circumstances of prolonged breast-feeding (e.g., nocturnal ad libitum breast- or bottle-feeding) are associated with early childhood caries.
Dental caries is a multifactorial infectious disease with many levels of complexity related to host and parasite factors, including diet (i.e., not simply one dietary factor such as breast milk), oral flora, salivary content (quality and quantity produced), and mineralization and morphology of dental structures (enamel and dentin). Therefore, obtaining the “last word” on the cariogenicity of dietary substances such as human milk is difficult.
We certainly did not mean to imply that there was any detrimental effect of breast-feeding on oral development. Alternatively, nonnutritive sucking habits are another area of much controversy. Factors such as frequency, duration and intensity are extremely important in determining the risk for adverse effects on oral development. However, most dental practitioners agree that this is not usually a serious problem before eruption of permanent teeth.