ISW for the Treatment of Angle Class II Division 1 Combined with Unstable Mandibular Position
Kuo Li-Ling1, Yu Chien-Chih2, Wu Wei-Te3, Yu Jian-Hong1*
1Department of Orthodontics, China Medical University Hospital, Taichung City, Taiwan
2School of Pharmacy, College of Pharmacy, China Medical University, Taichung, Taiwan
3Department of Biomechatronics Engineering, National Pingtung University of Science and Technology, Pingtung County, Taiwan
*Corresponding Authors: Yu Jian-Hong, Department of Orthodontics, China Medical University Hospital, No. 2, Yude Road, North District, Taichung City 404, Taiwan, R.O.C.
Received: 01 April 2020; Accepted: 09 April 2020; Published: 21 April 2020
Citation: Kuo Li-Ling, Yu Chien-Chih, Wu Wei-Te, Yu Jian-Hong. ISW for the Treatment of Angle Class II Division 1 Combined with Unstable Mandibular Position. Dental Research and Oral Health 3 (2020): 035-051.View / Download Pdf Share at Facebook
Introduction: This article presents a case of Angle Class II division 1 with completed treatment. We used improved super-elastic Ti–Ni alloy wire (ISW) and the modified multiloop edgewise arch wire (MEAW) technique to create space and to relieve anterior and posterior crowding in an adult female patient with poor dental alignment and facial asymmetry. Intermaxillary elastics were also used to improve the mandibular position and intercuspal interdigitation. The patient was treated by crowding relief, facial asymmetry correction, the MEAW technique, and overjet reduction.
Findings: The patient was treated successfully using ISW.
Conclusion: In this case, we rapidly corrected poor dental alignment by using ISW and the MEAW technique. Compared with conventional stainless steel wire treatment, ISW provides an efficient and easy approach to correct such malocclusion. Successful treatment outcomes were attained, and the patient was pleased with the treatment results.
Angle Class II division 1, Facial asymmetry, ISW, MEAW
A 28-year-old woman visited our clinic with a chief complaint of poor dental alignment and facial asymmetry. Clinical examination revealed Angle Class II division 1. We used improved super-elastic Ti–Ni alloy wire (ISW) [1, 2] and the multiloop edgewise arch wire (MEAW) technique to create space and to relieve anterior and posterior crowding. Intermaxillary elastics (IME’s) were also used to achieve a more suitable mandibular position and intercuspal interdigitation. Finally, correction of arch coordination, space management, and bite control were achieved.
2. Case Report
This case report describes an adult female patient with poor dental alignment, facial asymmetry, and dental crossbite. The aforementioned problems were successfully treated using ISW and the MEAW technique.
3. Diagnosis and Etiology
A 28-year-old woman with a convex profile visited our clinic for an orthodontic consultation. The extraoral and frontal profile revealed adequate incisor exposure and an upper midline with no deviation from the facial midline (Figure 1). Clinical examination revealed Angle Class II division 1 and a lower right second premolar crossbite (Figure 2).
Panoramic radiography revealed the presence of #18, #28, and #48 wisdom teeth, an endodontically treated tooth (#47), and no unerupted teeth; however, signs of erosion were noted on the left mandibular condyle head (Figure 3). The cephalometric film indicated a skeletal Class II resulting from minor maxillary protrusion, a convex facial type (ANB: 6.1°), and a mandibular plane angle of 24.3°. Many parameters were not within ideal ranges. The posterior–anterior view revealed that the mandibular had shifted to the right. Clinical examination revealed no signs of bad habits (Figure 4, Figure 5 and Figure 6).
4. Treatment Objectives
The patient chiefly complained of poor dental alignment and facial asymmetry. The first priority was to address the chief complaint by achieving a molar Class I relationship and facial symmetry. Other objectives were to correct the crowding and the #45 crossbite, improve overjet and overbite, and obtain more suitable arch coordination and individual normal occlusion.
5. Treatment Plan
- #18, #28, and #48 extraction
- Full-mouth direct bonding system (DBS) and ISW leveling
- Observation of mandibular response .
- Use of the MEAW technique and IME’s for improved interdigitation and achievement of a molar Class I relationship.
6. Treatment Progress
After a detailed explanation and discussion, the patient agreed to receive the aforementioned orthodontic treatment. ISW (developed by Tokyo Medical and Dental University, Japan) has super-elastic, shape memory, and shock and vibration absorption properties. This paper describes the experience in treating a patient with Angle Class II division 1 using ISW combined with IME’s. This helped the patient gain an esthetically pleasing smile, with which she was satisfied. On November 28, 2016, we applied the DBS with 0.018 × 0.025-inch brackets over the upper and lower arches. We used a 0.016 × 0.022-inch ISW to level the teeth for 1 month; preliminary leveling and alignment were gradually achieved (Figure 7). On December 28, 2016, 1 month after commencing active treatment, the MEAW technique was used to correct the crossbite at #45. MEAW was applied in the lower right at #46 and #47, and an open coil spring was used between #43 and #45 to create a space for #44 (Figure 8). On March 27, 2017, 4 months of active treatment, the crossbite at #45 was corrected. Lower right MEAW at #45, #46, and #47 and lower left MEAW at #36 and #37 were placed. The lower anterior teeth flared out because MEAW was used without IME’s to reduce the overjet. An open coil spring was placed between #34 and #35 for midline correction (Figure 9).
On April 17, 2017, MEAW was placed in the upper posterior to achieve a molar Class I relationship. Class II IME was used for space creation to facilitate #12 and #22 derotation and to achieve an improved canine and molar relationship (R: #13–#45; L: #23–#35; Figure 10). On February 15, 2018, after 15 months of active treatment, #12 and #22 were appropriately positioned. To reduce the overjet, MEAW was placed in the upper posterior, and Class II IME was also used (R: #13–#45; L: #23–#35; Figure 11). On October 24, 2018, after 23 months of active treatment, a molar Class I relationship was achieved. IME’s were used to improve cusp interdigitation and the canine relationship (Figure 12).
7. Treatment Results
After 23 months of active treatment, extraoral and intraoral appearance was improved. A straight profile, lower facial height, and correlated facial midlines were achieved (Figure 13). Intraoral Class I canine and molar relationships were also achieved with favorable interdigitation, normal overbite and overjet, and suitable curve of Spee. The patient’s smile arc became more harmonious after treatment (Figure 13 and Figure 14). Post-treatment panoramic and cephalometric analyses (Figure 15, Figure 16 and Figure 17) and the superimposed cephalometric tracings (Figure 18 and Figure 19) demonstrated considerable improvement.
Pretreatment and post-treatment dental analyses revealed a change in the U1 to FH plane from 109.5° to 110.0° and a change in the L1 to mandibular plane from 100.9° to 115.0°; dental change were acceptable. At the end of the treatment, we provided the patient with a circumferential retainer for the upper arch, a Hawley retainer for the lower arch, and an auxiliary clear plastic retainer for retention . The treatment outcome remained stable during several follow-up visits.
We used MEAW and flare-out for crowding relief. Crowding relief was achieved through five procedures: extraction, stripping, expansion and flare-out, MEAW, and distalization. The MEAW technique allows the posterior teeth to tip back and intrude. With anterior teeth flaring out, a space was created, correcting the position of the crossbite tooth. Some problems also required our attention. The MEAW technique may increase the risk of posterior teeth disocclusion. Profile protrusion and interarch coordination are potential side effects when anterior teeth flare out (Figure 20). Chia et al. indicated that asymmetries have pathological, traumatic, functional, or developmental causes . Haraguchi et al. revealed that the etiology of facial asymmetry can be grouped into hereditary factors of prenatal origin and acquired factors of postnatal origin . In this case, the patient’s asymmetry likely resulted from #45 crossbite, which is a functional problem. In the P-A view, we observed that her mandible was corrected to the left at 2°. Following treatment, her facial appearance greatly improved. We observed no symptoms of left condyle erosion, and no signs of its deterioration were noted during the orthodontic process; this may contribute to an increasingly stable occlusion  (Figure 21).
The characteristics of ISW simplify the MEAW technique. Serial step-up and tip-back bends were performed using a heat bender. The dentition must first be prepared for the use of this mechanism by eliminating all rotations, spaces, crowding, or poorly positioned brackets . By using the MEAW technique, uprighting, distal tipping, and even relative intrusion for tooth control can be performed. In this case, we used the MEAW technique with IME to improve the molar and canine relationship. We also used the MEAW technique without IME to flatten the curve of Spee. The tip-back degree of the lower first molar changed from 86° to 77° (9° of difference). The tip-back degree of the upper first molar changed from 82° to 72° (10° of difference; Figure 22). Overjet is measured from the labial surface of the most prominent incisor to the labial surface of the mandibular incisor; the distance is typically 2.0~4.0 mm (0.079~0.157 in). If the lower incisor is anterior to the upper incisor, the overjet is given a negative value . In this case, we wanted to achieve a more favorable overjet; therefore, overjet reduction was necessary. First, we used the MEAW technique without IME to allow the lower anterior teeth to flare out. Thus, the overjet was reduced from 6.0 to 3.5 mm within 14 months. Then, MEAW was placed on the upper posterior teeth with IME. The overjet decreased as a result of upper anterior teeth retraction and mandible protraction. The overjet decreased from 3.5 to 3.0 mm within 8 months. IME’s were also used to improve the mandibular position and intercuspal interdigitation [10, 11] (Figure 23).
9. Summary and Conclusions
We rapidly corrected poor dental alignment by using ISW and the MEAW technique. Compared with conventional treatment with stainless steel wire, ISW provides an efficient and easy approach to correct such malocclusion. Successful treatment outcomes were obtained, and the patient was pleased with the results.
This work was supported by China Medical University and Hospital, Taichung City, Taiwan (Grant number: CMU105-S-30). This manuscript was edited by Wallace Academic Editing. No specific funding was received for this report.
Availability of Data and Materials
The materials are available upon request.
YJH was responsible for treatment planning. YJH was responsible for clinical patient treatment. KLL, YCC, WWT, and YJH drafted the manuscript. All authors read and approved the final manuscript.
Ethics Approval and Consent to Participate
The procedures performed in this study were in accordance with the wishes of Ms. Ko. This case report and the treatment plan were approved by the chairman of the Department of Orthodontics, China Medical University.
Consent for Publication
Written informed consent was obtained from the patient for publication of this short report and any accompanying images.
Conflict of Interest
The authors declare that they have no competing interests.
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