Correction of deep overbite and gummy smile by using a mini-implant with a segmented wire in a growing Class II Division 2 patient.

摘要

A boy, aged 10.5 years, with a Class II molar relationship and a very deep overbite, complaining of a gummy smile and anterior crowding, was treated nonextraction with a mini-implant and Twin-block and edgewise fixed appliances. Severely extruded and retroclined maxillary incisors were intruded and proclined with a nickel-titanium closed-coil spring anchored to a mini-implant and segmented wires; this resolved the gummy smile and deep overbite efficiently without extruding the maxillary molars or opening the mandible. The mandibular incisors were proclined without direct orthodontic force during intrusion of the maxillary incisors; this helped the nonextraction treatment of mandibular incisor crowding. The Twin-block appliance with high-pull headgear promoted mandibular growth, restrained maxillary growth, and changed the canine and molar relationship from Class II to Class I. The patient's overbite and overjet were overtreated, and, 1 year postretention, the patient maintained a good overbite and overjet.