Can the Relationship Between Breastfeeding and Malocclusion in Primary Dentition Change According to Pacifier Use...

To investigate whether the association between exclusive breastfeeding and malocclusions in primary dentition is modified by pacifier use duration and intensity.

Data from a birth cohort study conducted in southern Brazil were used (n = 3591). Poisson regression with robust error variance was used to assess the association between exclusive breastfeeding and malocclusion. The exposure to exclusive breastfeeding was collected through information about breastfeeding duration at 3 and 12 months follow ups. Malocclusion outcomes were assessed at 48 months of follow up using criteria of the World Health Organization. Effect measure modification (EMM) analysis was adopted to verify the association between exclusive breastfeeding and malocclusions, which vary according to pacifier use duration and intensity. EMM was assessed by means of the relative excess risk due to interaction (RERI), which corresponds to the additional risk that would be expected if the combination of exclusive breastfeeding and pacifier use intensity and duration was fully additive.

Children who were not exclusively breastfed for 6 months and who used a pacifier throughout the first 4 years showed a prevalence of 7.82 higher than malocclusion (95% CI 4.70-12.92). Even among children who were exclusively breastfed, pacifier use during this period was also associated with a higher prevalence of malocclusion (PR 5.98; 95% CI 3.50-10.21). When occurrence of malocclusion by pacifier use intensity at 48 months was analysed, children full-time users and those children who were not exclusively breastfed presented a malocclusion prevalence of 4.87 (95% CI 3.43-6.93), and those children who were full-time users and who were exclusively breastfed showed a prevalence of 3.96 higher for malocclusion (95% CI 32.66-5.90). Positive RERI for both duration and intensity of pacifier use were observed, suggesting that the joint effect of breastfeeding and pacifier use on malocclusion is larger than the sum of their individual values.

Pacifiers use duration and intensity in the first 4 years of life modify the protective effect of exclusive breastfeeding for the first 6 months of life on the malocclusion prevalence at 48 months of life. These findings reinforce the deleterious effects of pacifier use on occlusal development, even with the practice of exclusive breastfeeding.