Classification and Treatment of Angle Class II Subdivision Malocculsions
Cassidy, Sara Elizabeth
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<bold>Introduction:</bold> Patients with Class II subdivision malocclusions are a challenge for clinicians because re-establishing symmetry in one or both arches is often a treatment goal. In patients with a mandibular skeletal asymmetry, surgery is often one of the treatment options. However, patients may be unwilling to undergo surgery, and other options may have to be considered. The aim of this study was to evaluate the etiology and outcomes of Class II subdivision patients treated at the University of Washington Graduate Orthodontic Clinic from 1995-2011. <bold>Methods:</bold> A search of patients treated between 1995 and 2011 resulted in the identification of 110 consecutively treated Class II subdivision subjects with complete records. Ninety-eight subjects could be classified into 1 of 3 groups, based on midline position and dental/skeletal etiology. Initial and final models were used to measure PAR, midlines, overjet, overbite, and molar position. Initial and final cephalograms were traced and measured. Charts were reviewed for information regarding treatment. <bold>Results:</bold> Twenty-five percent of the 98 subjects presented with their maxillary and mandibular midlines coincident with the face, and were due to a maxillary dental asymmetry. Another 15% presented with maxillary midlines deviated from facial, and were also due to a maxillary dental asymmetry. About 50% of the subjects presented with mandibular midlines that were not coincident with facial, and most of these patients exhibited some degree of mandibular skeletal asymmetry. Over the past 15 years, treatment strategies employed at the University of Washington indicated trends toward less surgery, extractions, and headgear, and towards more reliance on fixed functional use. Ideal correction of midlines was not always achieved, especially in the case of mandibular skeletal asymmetry, with under-correction occurring more commonly than over-correction. Final PAR scores were comparable, regardless of the origin of the asymmetry or extractions status. Lower incisor proclination was increased when fixed functional appliances were used, as well as when a Class I molar relationship was the target for the Class II side. <bold>Conclusions:</bold> Class II subdivision malocclusions were grouped into 3 main categories, with the largest category being mandibular asymmetry. Interesting trends were noted with regard to treatment strategies, midline and molar correction, and lower incisor proclination.
- Dentistry