I was interested in the article by Maja Ovsenik in the September issue (Incorrect orofacial functions until 5 years of age and their association with posterior crossbite. Am J Orthod Dentofacial Orthop 2009;136:375-81).

Clearly, abnormal swallowing is an important factor in the etiology of many crossbites and other malocclusions, but it is difficult to find consensus on the type of swallowing that is preferable, let alone “ideal.” Dr Ovsenik stated that the “swallowing pattern matures from infantile to somatic type in most children from the ages of 2 to 4 years,” but she gave no evidence for this, and I have heard many different suggestions from various experts.

My contacts with the La Leche League suggest that infants suck until they first learn to swallow, sometime between 12 and 18 months old. Early weaning with soft food by using a spoon seems to encourage tongue-between-gum-pad swallowing, which is likely to develop into tongue-between-tooth swallowing subsequently. This in turn is associated with enlarged buccinators and collapsed arches, and could be a major cause of crossbites and collapsed arches.

It has always surprised me that there is little evidence to show that breastfeeding has much influence on malocclusion, but the age of weaning might prove to be a more significant factor. Recently, there has been a move in the United Kingdom toward “demand weaning,” or allowing the infant to start eating harder foods at will. This seems to be more in line with circumstances in natural environments.

I would be interested in the views of experts in this field, since it seems to be an important subject with little firm evidence to guide us.