## 3 Clinical Case Demonstrations
### Unilateral Ditalization Case  
An adolescent patient presented with significant maxillary and mild mandibular anterior crowding, maxillary right lateral incisor in crossbite, and end-on Class II on the right first molar and canine. The patient had no significant past medical or past dental history. Intraoral examination showed the patient was in permanent dentition with all the second molars partially erupted (Figure 6). Anterior-posteriorly, the patient presented Class I canine and molar relationships on the left side, and Class II canine and molar relationships on the right side. The maxillary left lateral incisor was edge-to-edge with the mandibular left lateral incisor and canine, and the maxillary right lateral incisor was in crossbite. The maxillary incisors were slightly retroclined and normtorusive, while the mandibular incisors were normoclined and normtorusive. The maxillary dental midline was 1 mm to  
Figure 3: The intraoral progress photos of case 1 demonstrate the bilateral super class I molar relationship achieved with the modified Nance appliance technique. The photos of the right buccal, front, and left buccal views were taken at the same time as the middle photo in Figure 2.  
Figure 2: The intraoral progress photos of case 1 demonstrate the treatment sequence of the maxillary arch with the modified Nance appliance technique. From left to right, the maxillary arch photos represent: the delivery of modified Nance appliance (**left**); the end of molar distalization with modified Nance appliance (**middle**); the initiation of maxillary arch leveling and aligning with NiTi archive, and left premolar distalization with power chain after delivering a new Nance appliance and repositioning the brackets (**right**). In the middle photo, the termination of molar distalization was determined by achieving a super Class I molar relationship on both sides, as demonstrated in Figure 3.  
the right of the facial midline, and the mandibular dental midline was coincident with the facial midline. There was no posterior crossbite, and the curve of Wilson was within the normal limit. Both the overbite and the curve of Spee were within the normal limit. There was mild crowding in the mandibular arch. No significant Bolton discrepancy was detected.  
The treatment objectives were to (1) distalize the maxillary right quadrant and canine to a Class I relationship; (2) maintain the Class I canine and molar relationship on the left side; (3) correct the maxillary midline and anterior crossbite to achieve ideal overbite and overjet; and (4) correct the mandibular mild crowding.  
Based on the treatment objectives, the treatment plan was designed as follows: (1) unilateral right maxillary molar distalization with the modified Nance appliance technique, then distalizing the maxillary premolars and canines to achieve Class I canine and molar relationships on the right side without using the Class II elastics; (2) slightly procline the uprighted maxillary incisors, correct the anterior crossbite and coordinate the midline; (3) level and align the mandibular arch, slight interproximal reduction to help correct the crowding. The treatment plan was well-accepted by the patient and parents.  
Figure 4: The intraoral progress photos of case 1 demonstrate maxillary arch space closure.  
Figure 5: The final intraoral photos of case 1.  
The modified Nance appliance was delivered with mash pads cemented to four maxillary premolars as anchorage. The distalization of molars was performed with the right side of the maxillary arch (Figure 7, top) until a super Class I molar relationship was achieved (Figure 7). The subsequent treatment sequence was the same as described above. At the end of the treatment, satisfactory dental alignment, bilateral Class I canine and molar relationships, and ideal overjet and overbite were achieved (Figure 8). In addition, dental midlines were coincident with the facial midline, and protrusive and canine guidance was obtained.