Harberson V A, Myers D R
Am J Orthod. 1978 Sep;74(3):310-3. doi: 10.1016/0002-9416(78)90207-5.
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.
