Midpalatal suture opening during functional posterior cross-bite correction.

The purpose of this study was to determine whether opening of the midpalatal suture occurs during treatment of posterior cross-bites by means of a Porter or W appliance. In eight of the ten cases treated there was radiographic evidence of midpalatal suture opening. Posterior cross-bite correction with a Porter of W appliance may occur either by a combination of midpalatal suture opening and buccal tipping of posterior teeth or by buccal tipping alone.