Arch width and form: a review.

A study of the literature reveals a variety of opinions on the potential for change in arch dimensions. The variations in sample sizes, treatment mechanics, and retention regimens may obscure relevant findings. These articles confirm some common findings, and a number of clinical cases are presented to illustrate these trends. It would seem that limited degrees of arch expansion can be produced regularly, but careful case selection is necessary. Arch expansion is most likely to be achieved in the growing patient with correction of crossbites, correction of a Class II malocclusion, and achievement of a good intercuspation without extractions.