# Nonsurgical Correction of Anterior Crossbite with Extra-Radicular Miniscrews--A Case Report
## 4 Discussion
The criteria for case selection in this approach would be the same as those with camouflage treatment of Class III malocclusions, including (1) mild to moderate skeletal discrepancy, (2) none or minor dental compensation, (3) an acceptable profile except for period imbalance,  
Figure 17: Case 2, (**A**), Lateral cephalogram in the 4 th month of treatment right after the correction of anterior crossbite; (**B**), Cephalometric superimpositions of pretreatment and the 4 th month show that most of the correction of anterior crossbite was due to proclination of the upper incisors, even though the mandibular arch was distalized a bit with TSADs on the buccal shelves; (**C**), Cephalometric superimpositions of posttreatment and the 4 th month shows full arch distalization of both maxillary and mandibular arches to reduce the protrusion after anterior crossbite correction. Figure 18: Case 2, profile comparisons. (**A**), Pretreatment; (**B**), Nonextraction approach with the mandibular arch distalization with TSADs; (**C**), Posttreatment with full arch distalization with TSADs on both arches. and (4) sufficient clearance for whole dentition distalization. The third molars should be removed before whole arch distalization. The skeletal boundaries of the dentition should be checked carefully. [PERSON] et al. reported the average amount of distalization of the maxillary first molar to be 3.8 mm at the crown level and 3.2 mm at the root level and also reported that the average amount of distalization of the mandibular first molar to be 3.5 mm at the crown level and 1.8 mm at the root level [33; 34]. [PERSON] et al. suggested that 3 mm of mandibular arch distalization can be expected in Class III malocclusion cases and highlighted the mandibular posterior anatomic limit (MPAL) to be the lingual cortex of the mandibular body [53]. Examination with cone-beam computed tomography (CBCT) might be needed for precise prediction. Aside from the mandibular posterior limit, the maxillary and mandibular lingual cortical plates and maxillary tuberosity determine the potential boundaries of tooth movement. Soft tissue boundaries of dentition should also be observed clinically. However, the mandibular posterior anatomic limit might be the most critical limiting factor with this treatment modality. In addition, patients need to be informed that the camouflage Class III treatment is primarily dental compensation of skeletal discrepancies, which might not be as ideal as the treatment results with the surgical approach. The positions of TSADs at the buccal shelves are extra-radicular rather than interradicular (Figure 19) [38; 43; 47]. This is critical for this nonextraction approach, so the TSADs do not interfere with the root movement. The implant sites on the mandible are at the buccal shelves between the mandibular first and second molars. The flatter platform of the buccal shelf and more attached gingiva make this location favorable for placing a miniscrew. We suggest limiting the insertion point to somewhere within the mucogingival line. Suppose the attached gingiva is not wide enough for favorable miniscrew insertion. In that case, it is advised to insert the miniscrew as close to the mucogingival line as possible (within 1 mm) to minimize possible soft tissue irritation. The TSADs should be inserted perpendicular to the platform as possible on the buccal shelf, parallel to the mandibular molar roots, and into the bone until the proper amount of head exposure is achieved. The area only requires local infiltration of analgesia without any flap or pilot drilling, so a screwdriver is the only tool that will be necessary. Stainless steel miniscrews are preferred for safety reasons to avoid breakage during self-drilling. For more difficult insertions, a high-speed diamond round bur might be needed to make an indentation to catch the tip of the miniscrew for buccal shelf TSADs insertion. The insertion technique is quite simple and safe.