Relationship Between Breastfeeding and Malocclusion of Primary Dentition Among Premature Infants
by Anne Eglash MD, IBCLC, FABM
According to the authors of this week’s study, prematurity has an impact on several tissues and organs, such as smaller head circumference, lower muscle mass, shorter stature, all of which may play a role in how the teeth develop and line up.
Malocclusion is defined as a misalignment of the oral dentition, such as crowded teeth, crossbites, or overbite.
Studies have shown in the past that long duration of pacifier use, such as over 3 years, can cause malocclusion, and that breastfeeding is associated with less malocclusion of primary dentition in term infants. This is because facial muscle use during breastfeeding helps to guide appropriate development of oral structures, such as the jaws and hard palate.
Premature infants are more likely to use pacifiers frequently and are at higher risk of not directly breastfeeding. The authors were therefore interested in the association between preterm birth and malocclusions in 5-year old children, and the effects of breastfeeding and pacifiers.
This was a birth cohort study in Brazil of 1129 children, 11.9% of whom were born premature. At 24 hours postpartum, the mothers were asked questions regarding their environment, demographics, socioeconomics, and details of labor & delivery. The dyads were followed closely over the next 5 years, with questionnaires and visits. At 5 years of age, each child underwent formal dental exams.
The authors found that, among premature infants, pacifier use was significantly associated with more malocclusion, and breastfeeding was associated with significantly less malocclusion.
- Breastfeeding for more than 9 months eliminated the risk of malocclusion associated with prematurity.
- The longer a child was breastfed the lower the risk of malocclusion.
- Children who were born premature had twice the risk of malocclusion compared to those born term.
- Pacifier use among premature infants had a more harmful effect on malocclusion as compared to pacifier use among term infants.
See the Answer
Little is known about the influence of biological characteristics on the occurrence of malocclusion. This study aimed to investigate the association between preterm birth and primary-dentition malocclusion and how breastfeeding and the use of pacifiers are related to this association.
A representative sample (n = 1129) of children from the 2004 Pelotas, Brazil birth cohort study underwent a dental examination at age 5 years. Malocclusions were diagnosed according to the World Health Organization criteria, and the outcome was considered as the presence of moderate or severe malocclusion (MSM). Questionnaires including the children's oral health information were completed by the mothers. Data on socioeconomic status, breastfeeding, and preterm birth were obtained from previous follow-ups. Poisson regression analysis was conducted, followed by an interaction test.
The prevalence of MSM was 26.3% (95% confidence interval [CI], 23.6%-29.1%) in the total sample, 24.1% (95% CI, 21.5%-26.9%) in full-term births, and 42.2% (95% CI, 39.1%-45.3%) in preterm births. After adjustment, the prevalence of MSM was 42% higher in preterm births. Breastfeeding duration and pacifier use up to age 4 years modified the effect of gestational age on MSM.
Preterm birth is associated with the development of MSM. Breastfeeding reduces the effect of preterm birth on MSM, and pacifier use strengthens this association. Dentists should be aware that preterm birth may be a risk factor for malocclusion in primary dentition. The findings reinforce the benefits of breastfeeding on occlusal development and the negative consequences of pacifier use.
The Baby Friendly Hospital Initiative discourages pacifier use early postpartum so that all suckling happens at the breast. However, premature infants in US hospitals do not have free access to their lactating parent. Pacifiers have been considered reasonable for infants in the neonatal intensive care unit for calming, pain relief, stress management and during tube feeding. In order to reduce the risk of malocclusion associated with pacifier use, it would be ideal to minimize its use once the infant is home. This means avoiding routine use during the day, by soothing the infant in other ways, or feeding the infant when feeding cues are present, rather than holding off with a pacifier. Once an infant falls asleep with a pacifier, take it out.