Comparison of Two Tooth-borne Expanders in Rapid Maxillary Expansion

Rapid maxillary expansion using the Hyrax expander. Appliance anchorage will be performed by bands adapted to the first maxillary molars and arms of the screw contoured to adapt to palatal faces of the first and second maxillary bicuspids, in wich will be bonded by resin. The screw will be positioned perpendicularly to the palate sagittal midline, between second maxillary bicuspids and first maxillary molars, and 5 mm apically from marginal gingiva of palatal face of the first maxillary molars.The activation protocol will be 2 turns a day up to obtain transverse overcorrection. After the active period of RME, the screws will be fixed with ligature wire and the appliance will be kept as a retainer for 6 months.

Rapid maxillary expansion using the mini Hyrax expander. Appliance anchorage will be performed by bands adapted to the first maxillary molars and arms of the screw contoured to adapt to palatal faces of the first and second maxillary bicuspids, in wich will be bonded by resin. The screw will be positioned perpendicularly to the palate sagittal midline, between second maxillary bicuspids and first maxillary molars, and 5 mm apically from marginal gingiva of palatal face of the first maxillary molars. The activation protocol will be 2 turns a day up to obtain transverse overcorrection. After the active period of RME, the screws will be fixed with ligature wire and the appliance will be kept as a retainer for 6 months.