Case Report Table 1. Pretreatment Cephalometric Measurements Norm Cephalometric Measurement SNA (°) SNB (°) ANB (°) Wits (mm) FMA (FH-MP) (°) SN-MP (°) Figure 3. Pretreatment digital dental models at age 18 years and 6 months U1-NA (mm) U1-SN (°) L1-NB (mm) IMPA (L1-MP) (°) Upper lip to E line (mm) Lower lip to E line (mm) (Caucasian) 82.0 80.0 2.0 0.0 25.0 32.0 4.0 104.0 4.0 90.0 −4.0 −2.0 Pretreatment 74.6 79.0 −4.4 −6.4 18.1 36.7 −0.2 84.4 5.2 81.6 −8.5 1.1 Figure 4. Pretreatment radiographs at age 18 years and 6 months N-A horizontal length of −8.3 mm in addition to a normal mandibular length of 106.5 mm indicated that the skeletal discrepancy was primarily attributed to her retrusive maxilla (Figure 4 and Table 1). The ABO Discrepancy Index score was 55 (Figure 5). Figure 5. ABO Discrepancy Index Summer 2023 PCSO Bulletin 71