Correction of a skeletal Class II malocclusion with severe crowding by a specially designed rapid maxillary expander.

To correct an Angle Class II malocclusion or to create spaces in the maxillary arch by nonextraction treatment, distal movement of the maxillary molars is required. Various modalities for distalizing the buccal segment have been reported. Conventional extraoral appliances can be used to obtain maximum anchorage. However, many patients reject headgear wear because of social and esthetic concerns, and the success of this treatment depends on patient compliance. Intraoral appliances, such as repelling magnets, nickel-titanium coils, pendulum appliance, Jones jig appliance, distal jet appliance, and modified Nance appliance, have been introduced to distalize the molars with little or no patient cooperation. However, intraoral appliances can result in anchorage loss of the anterior teeth and distal tipping of the maxillary molars. In this case report, we introduce a diversified rapid maxillary expansion appliance that was custom designed and fabricated for the treatment of a growing girl with a skeletal Class II malocclusion and severe crowding from a totally lingually positioned lateral incisor. The appliance concomitantly expanded the maxilla transversely and retracted the buccal segment sagittally, distalizing the maxillary molars to reach a Class I relationship and creating the spaces to displace the malpositioned lateral incisor. The uniqueness of this special diversified rapid maxillary expansion appliance was highlighted by a series of reconstructions and modifications at different stages of the treatment to reinforce the anchorage.