Diagnosis and Conservative Treatment of Skeletal Class III Malocclusion with Anterior Crossbite and Asymmetric Maxillary Crowding

Abstract

A 28-year-9-month male presented for orthodontic consultation for skeletal Class III malocclusion (ANB -30) with a modest asymmetric Class II/III molar relationship, complicated by an anterior crossbite, deep bite, and 12mm of asymmetric maxillary crowding. Despite the severity of a malocclusion, Discrepancy Index (DI) = 37, the patient desired non-invasive camouflage treatment. Lin’s 3-Ring diagnosis revealed that treatment without extractions or orthognathic surgery was a viable approach. Arch length analysis indicated that differential interproximal enamel reduction (IPR) could resolve the crowding and midline discrepancy, but a miniscrew in the infrazygomatic crest (IZC) was needed to retract the right buccal segment. The patient accepted the complex, staged treatment plan with the understanding that it would require ~3.5 years. Fixed appliance treatment with passive self ligating (PSL) brackets, early light short elastics (ELSE), bite turbos (BTs), IPR, and IZC retraction opened the vertical dimension of occlusion (VDO), improved the ANB 20 and achieved an excellent alignment, as evidenced by a CRE of 26 and a Pink and White (P&W) dental esthetic score of 3. The worksheets for the DI, CRE, and P&W scores are attached within this case report.