JOURNAL OF DENTISTRY AND DENTAL MEDICINE (ISSN:2517-7389)

In this case, ISW (improved superelastic Ti–Ni alloy wire, commonly called a lowhysteresis wire, developed by Tokyo Medical and Dental University) was employed in the treatment of an adult facial asymmetry skeletal Class III case without extraction and surgery. A 23-year-old man came to our clinic with a chief complaint of poor bite and for esthetic consultation. A clinical examination revealed a bilateral Class III molar relationship with anterior crossbite and mild crowding with a lower midline deviated to the right. Active treatment included establishment of a crossbite arch in the upper arch by using an ISW without extraction and removal of the lower-right fixed bridge prosthesis. Using ISW and adequate Class III intermaxillary elastic traction meant that the malocclusion was corrected with a minimal orthodontic approach. Treatment was completed within 19 months, and a stable occlusion was achieved after the active treatment.

Correct differential diagnosis of skeletal, functional, and dental anterior crossbite malocclusion has always been critical in clinical practice. The limitation of dental compensation includes the surrounding bone quantity and level. Nonextraction treatment of Class III malocclusion in adult patients usually requires distal movements of the mandibular molars to establish Class I molar and canine relationships [1-3].

The patient was a 23-year-old Taiwanese man at the time of his initial visit. He came with a chief complaint of poor bite and for esthetic consultation regarding the upper anterior teeth. His profile was concave, and the frontal view showed facial asymmetry (Figures 1 and 2). His occlusion exhibited a bilateral Class III molar relationship and a Class I canine relationship. He presented with an anterior crossbite (overjet −4.0 mm), a deep bite (overbite −3.5 mm), and a lower midline deviation to the right side (2.0 mm). Upper and lower anterior dentition revealed mild crowding. Oral hygiene and gingival conditions were normal.

Cephalometric analysis showed a skeletal Class III jaw relationship (Figure2, Table 1). The patient had a combination of a prognathic mandible and retrognathic maxilla (SNA 88.8º, mean 81.82º; SNB 90.5º, mean 78.61º; ANB −1.8º, mean 3.28º). Vertically, he presented a short face, that is, a hypodivergent skeletal pattern (Frankfort-mandibular plane angle [FMA] 21.0º). Because he had an upper anterior crossbite, the interincisal angle was large at 139.6º, and the occlusal plane was relatively small (0.9º) due to the functional anterior crossbite. A temporomandibular joint (TMJ) radiograph showed no apparent irregularity over the condylar head (Figure 3). The diagnosis was skeletal Class III malocclusion with facial asymmetry. If the patient had preferred a full-mouth tooth alignment arrangement, the lower-right fixed prosthesis would have had to be removed (Figure 4).

A summary of the diagnosis is as follows:

1. Functional (+): anterior crossbite

2. Skeletal (±): ANB = −1.8 º, skeletal Class III tendency

3. Denture (+): upper incisor (UI) to Frankfort horizontal (FH) plane (109.7°)

4. Dental (+): existence of #38

5. Discrepancy (+): upper: right: −4.0 mm, left: −6.0 mm :

                                           lower right: −3.0 mm, left: −4.0 mm

The treatment plan included the following steps:

1. Extraction of #38

2. Full-mouth DBS (Direct bonding system) and leveling

3. Correction of the anterior crossbite using a crossbite arch

4. Confirmation of the mandibular position; long Class III IME traction to camouflage the esthetic concern

ISW was used for management of the 23-year-old patient presenting with functional anterior crossbite and facial asymmetry with maxillary and mandibular anterior dental crowding. The treatment objective was to achieve an ideal occlusion of the bilateral angle’s Class I canine and molar relationship.

Our treatment objectives were (1) to improve the patient’s facial profile, (2) to improve the skeletal jaw relationship as much as possible by removing the occlusal interference of the functional anterior crossbite and redirecting the change of mandible position in a downward, backward direction, (3) to accomplish desirable anterior occlusion for establishing functional occlusion, (4) to correct the midline deviation, and (5) to follow up the retention to assess the need for further treatment.

Because of the patient’s functional disharmony, we explained to him the high possibility of jaw movement if the functional interference of the anterior crossbite was removed. Also, bilateral upper first bicuspid extraction was possible if the patient had concerns about a protruding esthetic, as well as the possibility of removing the lowerright fixed prosthesis to correct the occlusal interference that was causing the mandibular shift, forming an asymmetrical facial profile [10]. We also informed him of the possibility of a surgical approach if he had a strong desire for profile improvement. The treatment alternatives included either extraction or nonextraction of the upper bicuspid, depending on the patient’s expectations of profile improvement. Because the patient preferred nonextraction, we thoroughly explained that if correcting the upper anterior crowding and crossbite resulted in further (subjective) concern of a protruding profile, extraction of the upper bicuspid would be an option during subsequent treatment.

Because IME traction could not be used over the lower dentition because of the lower-right fixed prosthesis, mandibular clockwise rotation would only contribute from if the upper molars were extruded. Mandibular clockwise rotation would enhance the reduction of the anterior overjet and offer improved vertical control; furthermore, because the patient preferred nonextraction and was unwilling to remove the lower-right fixed prosthesis, the treatment could only be accomplished by reassessing the treatment response regarding the correction of facial asymmetry and by using the ISW crossbite arch to tentatively remove the interference caused by the functional anterior crossbite.

Moreover, the patient strongly preferred nonextraction and nonsurgical treatment. 

Treatment started on February 12, 2014, with upper arch DBS and leveling with a 0.016-inch × 0.022-inch L&H Titan Wire (ISW) (Tomy International Inc., Tokyo, Japan) for relief of anterior crowding (Figure 5).

On May 16, 2014, the crossbite arch was set between #13 and #23 to correct the anterior crossbite (with crimpable stoppers placed mesial to the bilateral upper canines to form a central omega loop) (Figure 6). Also, Class III IME traction was used to raise the bite and to adjust the jaw relationship.

On July 9, 2014, after 5 months of active treatment, the anterior crossbite was corrected (Figure 7). The anterior teeth reached an edge-to-edge relationship using an open coil spring for creating space between #21 and #23, an elastic chain for correcting the upper midline, and IME traction for Class III jaw relationship correction.

Soon afterwards, derotation of #22 was performed, and on August 20, 2014, re-DBS of #22, #31, and #35 was applied and an elastic chain for correcting the lower midline was fitted (Figure 8).

On January 12, 2015, after 5 months, derotation was completed through re-DBS of #12, #11, and #21 and upper and lower leveling with a 0.016-inch × 0.022-inch ISW (Figure 9). The periodontal condition of #22 was confirmed by using periapical radiography (Figure10).

On March 16, 2015, panoramic radiography was used for reconfirmation, and re-DBS of #22, #32, #35, #43, and #44 was performed for ideal root parallelism to achieve more accurate root parallelism adjustment (Figure 11 and 12).

Finally, on June 10, 2015, an elastic chain for midline correction and right (3-3) and left (3-3) IME traction were used to consolidate the canine relationship and for final finishing and detailing (Figure13). 

On September 16, 2015, after 19 months of active treatment, debonding of the bracket was performed, and a circumferential retainer was placed in the upper arch and a Hawley retainer in the lower arch (Figure14).

Active treatment was completed within 19 months, and a stable occlusion was achieved. After 19 months of active treatment, including 18 months of multibracket appliance treatment, the anterior crossbite and facial asymmetry were corrected and a normal functional occlusion was established (Figure 15).

The patient’s profile had markedly improved, and the mandibular deviation had been corrected. A cephalometric superimposition (Figures 16 and 17, Table 1) showed that the anteroposterior relationship had improved (ANB −1.8˚→ −1.3˚). The UI had tipped labially (UI to FH plane 109.7° → 128.1°), with the SNA reduced (SNA 88.8˚ → 86.8˚). Because of the upper molar extrusion, the mandibular plane was camouflaged by a downward and backward clockwise rotation of the mandible (FMA 21.9˚ → 23.2˚).

The anterior overbite and overjet was ideal because of (1) the change in the lower incisor (LI) to the mandibular plane (88.8˚ → 90.2˚) and (2) the change of the FMA angle, but mostly because of the correction of the anterior crossbite resulting from (3) the change of U1 to the FH plane angle (109.7˚ → 128.1˚) (Figure 18). The interincisal angle was reduced and compensated mostly by the tooth movement of the UIs (U1 to FH plane angle change 18.4˚/2.5˚ = 7.36 mm change in the anterior overjet).

In the panoramic view, the root parallelism was excellent, and no apparent root resorption was found (Figure 12). A 2-year follow up (the patient was 27 years old) showed that he had a balanced esthetic profile and occlusion, and he was pleased with the result (Figure 19). A comparison of the post-treatment (25 years and 5 months) and 2-year retention (27 years and 5 months) cephalograms (Figure 20, Table 1) illustrates stable dentoalveolar and maxillomandibular relationships.