Case Report Initial Lateral Cephalometric Measurements Variable Norm Pre-Treatment SNA (º) 82.0 79.3 SNB (º) 80.0 75.3 ANB (º) 2.0 4.0 FMA (FH-MP) (º) 25.0 17.8 SN-MP (º) 32.0 31.2 4.0 3.6 104.0 101.5 U1-NA (mm) U1-SN (º) L1-NB (mm) 4.0 5.9 IMPA (L1-MP) (º) 90.0 102.9 Upper Lip-E Line (mm) -2.0 -9.3 Lower Lip-E Line (mm) -4.0 -7.3 Treatment Objectives The goal of treatment in the maxilla is to maintain its position in all three dimensions, since little skeletal change is expected due to growth. The goal of treatment in the mandible is to maintain the anteroposterior position with slight autorotation of the mandible to allow for relative advancement of the B point. Mandibular transverse width should be maintained. Crossbite correction will be achieved through dental expansion. The incisors should be proclined slightly to alleviate crowding and create room for the ectopic maxillary left canine. Proclination of the mandibular incisors should be minimal, as incisors are already proclined. Ideal overbite and overjet should be attained. The molars and canines should finish in a Class I relationship. The objective is to correct the Class II dental relationship with derotation and distalization of the maxillary molars. Vertically, extrusion of the posterior teeth should be avoided while the maxillary incisors are proclined, in order to establish ideal overbite. Transversely, aside from the dental expansion, we also hope to increase the intermolar width of the maxillary molars by derotation. Treatment Options 1. Comprehensive orthodontic treatment with dental expansion; Class II extraction pattern of maxillary first premolars and mandibular second premolars. 2. Comprehensive orthodontic treatment with dental expansion; extraction of maxillary and mandibular first premolars. 3. Comprehensive orthodontic treatment with dental expansion; non-extraction, distalization of the maxillary molars for Class II correction. 4. Comprehensive orthodontic treatment with dental expansion; extraction of the maxillary second premolars and mandibular first premolars, mandibular surgical advancement and genioplasty. Post-treatment description of Case M.S. begins on the next page. Winter 2017 PCSO Bulletin 43