Dental Caries
by Kathryn Orlinsky, Phd
If there is one phrase that strikes fear into the hearts of breastfeeding
mothers, that phrase is "dental caries." How does nursing six times a
night or staying attached to the nipple for hours at a time affect a child's
teeth? Severe dental caries which occurs in very young children is
referred to as baby bottle tooth decay, or as nursing caries. The first
term implies a strong link with artificial feeding practices, whereas the
second does not. Which is more accurate?
To understand the risks, we need to know what causes tooth decay.
Most cavities are caused by the bacteria Streptococcus mutans, which
are found in about 20% of children younger than fourteen months.11 The
bacteria feed on the sugars that are present on teeth. They metabolize
the sugar and secrete acid as a waste product. It is this acid which
erodes the tooth enamel. In other words, a cavity is no more than an
unchecked infection.3
Another bacteria, Lactobacillus, may also be involved in tooth decay.7,8
Lactobacilli counts were 100 times higher in plaque samples of
breastfed children with caries than in breastfed children without
caries.9
How does the infection get started? Bacteria from their mothers' mouth
often colonize babies' mouths. If a mother holds a pacifier in her mouth
or shares a spoon with her child, bacteria may be transferred form her
mouth to that of her child. For families with a history of dental
problems, every effort should be made to avoid these practices.
Keeping the teeth as clean as possible by brushing or wiping them after
meals can also impede the spread of infection.
Enamel defects play a very important though sometimes unrecognized
role in tooth decay. These defects are often inherited. Thus, family
history may put a child at risk for caries in two ways: the child may
inherit weak enamel from the genetic contribution of one or both
parents, and he may become infected with bacteria present in the
parents' mouths. Once the bacteria are present, a high carbohydrate
diet helps them to proliferate.
How does breastfeeding differ from bottlefeeding in affecting the rate of
this infection? There is a fundamental difference between the way
children feed from a bottle and from the breast. To begin with, the
position of the nipple is entirely different in these two scenarios. The
human nipple is drawn far back into the child's mouth, well beyond the
front teeth. The bottom front teeth are covered by the child's tongue
during suckling. By contrast, the bottle nipple is much closer to the
child's front teeth.
Liquid pools continually from the artificial nipple, little or no sucking is
required. This liquid leaves a constant coating over the teeth. If this
coating consists of a sugary liquid, any bacteria already present can
have a feast. In contrast, milk will stop coming out of the human nipple
when the baby ceases to suck at the breast. The child may swallow the
last mouthful of milk and keep the nipple in his mouth without getting
any more milk over his teeth. Because of these inherent differences
between breast and artificial nipples and bottles, breastfeeding
discourages the pooling of bacterial food sources whereas
bottle-feeding encourages it.
Not only does the act of breastfeeding discourage milk pooling in the
mouth, but the human milk itself is protective against dental caries. The
enzymes lactoperoxidase14 and lactoferrin,5 both found in breastmilk,
reduce oral bacterial counts.12 Lactoperoxidase also protects both the
mother's breast and the child's intestinal tract from infection.14 It is
important to note that expressed breastmilk delivered in a bottle will
pool in a child's mouth just like any other fluid. In addition, depending
on how the breastmilk is stored, the protective enzymes may be less
active or even destroyed.
Foods other than those obtained from breast or bottle also play an
important role in dental caries. Sticky sugary foods like candy or raisins
may be difficult to remove from tooth surfaces. Foods that are high in
carbohydrates such as breads also provide an ideal substrate for
growing bacteria. When breastfed children have dental caries, these
other aspects of their diet may be at fault.
Based on what we know about the mechanics of breastfeeding, as well
as the composition of human milk, it seems unlikely that breastfeeding
would contribute to tooth decay. The caries rates of breastfed children
versus artificially fed children bear this out. Overall, I found that the
frequency of dental problems decreased in the following
order:6,10,13,16,17
children who sleep with a bottle of juice or formula
children who use a bottle but do not sleep with it
children who breastfeed at night-sleeping with the nipple in their
mouths
children who breastfeed only during the day
In some studies, the content of the bottle was significant, with
sweetened beverages leading to up to four times more S. mutans
colonization than milk.4,11 In other studies, the liquid contained within
the bottles was less important than the time the bottle was given.2
Breastfed children can and do have caries, but at a greatly reduced
rate compared to children who are bottle-fed from birth.1,15 The fact
that some breastfed children do have problems with decay probably
correlates more with inherited weaknesses in the enamel, general care
of the teeth, and other non-milk foods consumed. In families which are
caries-prone, many dentists will recommend diligent teeth cleaning and
attention to diet, rather than weaning.
1.al-Dashti AA, Williams SA and ME Curzon. 1995.
Community Dent Health. Mar;12(1):42-47.
2.Ayhan H. 1996. J Clin Pediatr Dent. 20(4):313-316.
3.Berkowitz R. 1996. J Public Health Dent. 56(1):51-54.
4.Bowen WH, Pearson SK, Rosalen PL, Miguel JC and AY
Shih. 1997. J Am Dent Assoc. Jul;128(7):865-871.
5.Denisova II, Gennad'eva TIa, Zhdanova TV, Khristova M
and LB Khazenson. 1996. Zh Mikrobiol Epidemiol
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6.Harrison R, Wong T, Ewan C, Contreras B and Y Phung.
1997. ASDC J Dent Child. Mar;64(2):112-117.
7.Kirstila V, Hakkinen P, Jentsch H, Vilja P and J Tenovuo.
1998. J Dent Res. Jan;77(1):73-80.
8.Lehane RJ, Murray PA and MJ Deasy. 1997. Periodontal
Clin Investig. 19(2):17-21.
9.Matee M, Mikx F, Maselle S and W Van Palenstein
Helderman. 1992. Caries Res. 26(3):183-187.
10.Matee M, van't Hof M, Maselle S, Mikx F and W van
Palenstein Helderman. 1994. Community Dent Oral
Epidemiol. Oct;22(5 Pt 1):289-293.
11.Mohan A, Morse DE, O'Sullivan DM and N Tinanoff. 1998.
Community Dent Oral Epidemiol. Feb;26(1):12-20.
12.Roger V, Tenovuo J, Lenander-Lumikari M, Soderling E and
Vilja. 1994. Caries Res. 28(6):421-428.
13.Schwartz SS, Rosivack RG and P Michelotti. 1993. ASDC J
Dent Child. Jan;60(1):22-25.
14.Ueda T, Sakamaki K, Kuroki T, Yano I and S Nagata. 1997.
Eur J Biochem. Jan 15;243(1-2):32-41.
15.van Everdingen T, Eijkman MA and J Hoogstraten. 1996.
Jul;63(4):271-274.
16.Weerheijm KL, Uyttendaele-Speybrouck BF, Euwe HC and
HJ Groen. 1998. Caries Res. 32(1):46-50.
17.Weinstein P, Smith WF, Fraser-Lee N, Shimono T and J
Tsubouchi. 1996. ASDC J Dent Child. Nov;63(6):426-433.
Reprinted with Permission by the Author
© 1998 Kathryn Orlinsky
Kathy can also be found at Beyond One Year: Breastfeeding & Parenting Beyond the First Year
