Breastfeeding and occlusal development.

Data sourcesPubmed, Embase, Scopus databases and New York Academy of Medicine Grey Literature Report. There were no restrictions on language and publication dates.Study selectionTwo reviewers selected both prospective and retrospective studies of children who had either been exclusively breastfed or were mixed breastfed; who were in either the primary or mixed dentition, and malocclusion was assessed. The following malocclusion traits were included; Class 2 molar, open-bite, non-spaced dentition and posterior crossbite.Data extraction and synthesisData were extracted including type of dentition, type of malocclusion, breastfeeding data collection method, results, breast feeding malocclusion odds ratio (OR) and quality of the article. The ORs of associations between different lengths of breastfeeding and the various malocclusion traits were calculated.ResultsThirty-one studies were included in a qualitative synthesis, nine in the quantitative analysis. All studies were observational, a majority examining malocclusion in the mixed dentition. Two studies looked at associations between no breastfeeding and posterior crossbite, finding children not breastfed presented 1.7 times more posterior crossbite than those breastfed for between one and six months (OR = 1.70 CI 2.01-2.39). ORs were calculated for exclusive breastfeeding and posterior crossbite with different duration of breastfeeding, and duration of breastfeeding and posterior crossbite. With regard to open bite and breastfeeding the OR=1.76 (CI 0.55-5.61) comparing those who were breastfed for less than or more than six months. Children breastfed for up to six months presented 1.25 times more Class 2 molar relationships than those breastfed for over six months. Children breastfed for up to six months presented 1.73 times more non-spaced dentitions than those breastfed for over six months (OR =1.73, CI 1.35-2.22).ConclusionsBreastfeeding is a protective factor against posterior crossbites and Class 2 malocclusion in primary and mixed dentitions, with the protective effect increasing with the months of breastfeeding. There is no clear evidence for breastfeeding proving any benefit against other malocclusion risks; open bite and non-spaced dentitions.