CASE REPORT Anterior Open-Bite Correction with

CASE REPORT Anterior Open-Bite Correction with Miniscrew Anchorage and a Combination of Upper Lingual and Lower Labial Appliances JAE HYUN PARK, DMD, MSD, MS, PhD KIYOSHI TAI, DDS, PhD MIWA IKEDA, DDS

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ases of anterior open bite present a challenge to the orthodontist because of their complex etiology—involving dental, skeletal, soft-tissue, respiratory, neurological, genetic, and habitual factors—and their relatively high relapse rate.1-7 Temporary anchorage devices (TADs) and other nonsurgical alternatives have become increasingly popular in treating these patients.8 TADs allow for controlled tooth movement and prevent unwanted reciprocal movement of other teeth, making them an effective modality for closing anterior open bite by means of molar intrusion and counterclockwise mandibular rotation.8-14 This process produces vertical skeletal and soft-

Dr. Park

tissue changes comparable to those of orthognathic surgery.14 Moreover, the counterclockwise rotation of the mandible following molar intrusion increases mandibular prominence during Class II correction. Such movement is generally contraindicated, however, in Class III patients.14

Dr. Tai

Dr. Ikeda

Dr. Park is a Professor and Chair and Dr. Tai is a visiting Adjunct Professor, Postgraduate Orthodontic Program, Arizona School of Dentistry and Oral Health, A.T. Still University, 5835 E. Still Circle, Mesa, AZ 85206. Drs. Park and Tai are also Adjunct Professors, Graduate School of Dentistry, Kyung Hee University, Seoul, Korea. Drs. Tai and Ikeda are in the private practice of orthodontics, Okayama, Japan. E-mail Dr. Park at [email protected].

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ANTERIOR OPEN-BITE CORRECTION WITH MINISCREW ANCHORAGE

Fig. 1 23-year-old female patient with anterior open bite and lower anterior crowding before treatment.

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TABLE 1 CEPHALOMETRIC ANALYSIS

Norm Pretreatment Post-Treatment

SNA

82.0° 77.4° 76.2°

SNB

80.0° 72.7° 71.5°

ANB

2.0° 4.6° 4.7°

Wits appraisal

+1.1mm

+0.1mm

SN-MP

34.0° 42.7° 40.8°

FH-MP

28.2° 33.5° 30.7°

LFH (ANS-Me/N-Me)

55.0%

58.0%

–1.9mm

57.9%

U1-SN

104.0° 115.2° 89.0°

U1-NA

22.0° 37.8° 12.9°

IMPA

90.0° 110.0° 96.0°

L1-NB

25.0° 45.5° 28.4°

U1-L1

124.0° 92.0° 136.0°

Upper lip to E-line

1.2mm

6.6mm

0.3mm

Lower lip to E-line

2.0mm

6.1mm

1.3mm

The present article shows how anterior open bite can be corrected and the profile improved by impaction of the maxillary posterior teeth using upper lingual and lower labial appliances in conjunction with maxillary TADs.

Diagnosis and Treatment Planning A 23-year-old female was referred with the chief complaint of anterior open bite and lower anterior crowding (Fig. 1). She had a symmetrical face with a mesofacial pattern, protrusive lips with mentalis strain, and a convex profile. No symptoms of TMD were present, including pain, restricted jaw movement, or joint noise. The patient had a 3mm open bite, a 5.7mm overjet, and bilateral end-on Class II molar relationships. There was mild crowding in the maxillary arch and moderate crowding in the mandibular arch, with a flat curve of Spee. The maxillary dental midline was deviated 1mm to the right; the mandibular

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dental midline was coincident with the facial midline. Restorations were present on the upper premolars. The patient exhibited a tongue-thrust habit with forced opening of the lips when swallowing.15 The panoramic radiograph revealed all third molars; the lower third molars were developed and impacted. Cephalometric analysis indicated a hyperdivergent growth pattern, with an SN-MP angle of 42.7° (Table 1). Although a skeletal Class II pattern was seen (ANB = 4.6°), the Wits appraisal was comparatively low (+.1mm) because of the clockwise rotation of her jaws relative to the cranial reference plane (SN).16 Her upper and lower incisors were proclined (U1-SN = 115.2°, IMPA = 110°). Treatment objectives were to close the open bite, obtain normal overjet and overbite, improve the facial profile, establish Class I molar relationships, relieve the crowding, correct the dental midline, achieve a stable occlusal relationship, and improve facial and dental esthetics by establishing an attractive smile.

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The first treatment option was two-jaw surgery involving maxillary posterior impaction and mandibular advancement. The upper second and lower first premolars would be extracted to resolve crowding and improve incisor inclination. Concurrent mandibular advancement and an advancing genioplasty could be performed to move the chin forward. When presented with this option, the patient declined orthognathic surgery. The second alternative was to use the multiloop edgewise archwire technique (MEAW) to extrude the anterior teeth and upright the posterior teeth for open-bite closure.17,18 This option was ruled out because of the complexity of wirebending, the need for elastics, the patient’s poor oral hygiene, and the potential for soft-tissue irritation.19 Under the third alternative, the upper first premolars and lower second premolars would be extracted, and the anterior teeth would be retracted with maximum anchorage to correct the Class II molar relationship. The patient chose this option, but rejected the possibility of a genioplasty to improve the profile following orthodontic treatment.

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Treatment Progress After the extractions were performed, selfligating .018" × .025" lingual brackets* were bonded in the maxillary arch for esthetic reasons. In the mandibular arch, .018" × .025" preadjusted ceramic brackets** were placed on the labial side because of the shorter interbracket distances and moderate anterior crowding. After six months of leveling with continuous mushroom archwires, upper .017" × .025" stainless steel archwires were placed for en-masse anterior retraction with torque control. Miniscrews*** (1.6mm diameter, 8mm length) were placed in the palatal alveolar bone between the upper second premolars and first molars on each side to provide maximum anchorage during the retraction phase. Crimpable hooks were added to the mushroom archwires distal to the canines for attachment of elastomeric chains from the TADs (Fig. 2). The length of the crimpable hooks and the positions of the TADs were determined after locating the center of resistance for the six upper anterior teeth,20 using the lateral cephalogram and allowing for

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Fig. 2 En-masse retraction with elastomeric chains (not pictured) from crimpable hooks on lingual archwire to palatal temporary anchorage devices (TADs). A. Start of treatment. B. After two months of treatment. C. After six months of treatment.

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Fig. 3 Analysis of retraction force from TADs with different applications around center of resistance.

translational movement (Fig. 3).21-23 At the same time, the upper posterior teeth were intruded using elastic threads from the TADs to the archwires. Anterior torque was controlled with Class I elastics from the miniscrew heads to the crimpable hooks. The maxillary extraction spaces were closed within 11 months after TAD installation. The mandibular extraction spaces were then closed with .016" × .022" stainless steel archwires, using elastomeric chains between the crimpable hooks and first molars to retract the anterior teeth. Final detailing was accomplished with .016" ×.022" TMA† archwires. Total active treatment time was 26 months (Fig. 4). Upper 3-3 and lower 4-4 bonded lingual retainers and Essix‡ retainers were delivered after debonding.

Treatment Results All treatment objectives were achieved, including a significant improvement in the open bite and lip protrusion. Facial esthetic harmony was enhanced by retracting the anterior teeth, closing the mandibular plane following intrusion of the maxillary posterior teeth, and moving the mandible forward. Lower anterior facial height was reduced, and the mentalis muscle strain diminished. The anterior open bite was corrected by intrusion of the maxillary posterior teeth, along with extrusion and uprighting of the anterior teeth during retraction. The patient’s smile esthetics were substantially improved, although her maxillary dental midline was still deviated 1mm to the right

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while the mandibular dental midline remained coincident with the facial midline. Acceptable overbite and overjet and Class I canine and molar relationships were achieved. The patient did not report any TMJ pain or discomfort during or after orthodontic treatment. The post-treatment panoramic image revealed no signs of significant root or bone resorption, and acceptable root parallelism was observed. The patient was referred to an oral surgeon for extraction of all third molars. Post-treatment cephalometric analysis (Table 1) indicated skeletal changes due to forward movement of the mandible (ANB = 4.7°, Wits appraisal = –1.9mm) and a decrease in the mandibular plane angle (SN-MP = 40.8°). The upper incisors were slightly retroclined (U1-SN = 89°), and the lowerincisor proclination was reduced (IMPA = 96°). Esthetic soft-tissue profile changes were confirmed by the position of the upper and lower lips relative to the E-line. In conjunction with the reduced lip prominence, the counterclockwise mandibular rotation advanced the patient’s soft-tissue pogonion, which further improved her profile. Two years after treatment, records showed no significant relapse and a stable occlusion (Fig. 5). *STb, trademark of Ormco Corporation, Orange, CA; www.ormco. com. **Clarity, trademark of 3M Unitek, Monrovia, CA; www.3Munitek. com. ***O.S.A.S., DEWIMED Medizintechnik GmbH, Tuttlingen, Germany; www.dewimed.de. †Registered trademark of Ormco Corporation, Orange, CA; www. ormco.com. ‡Registered trademark of Dentsply Raintree Essix Glenroe, Sarasota, FL; www.essix.com.

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Fig. 4 A. Patient after 26 months of treatment. B. Superimposition of pre- and post-treatment cephalometric tracings.

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Fig. 5 Patient two years after treatment.

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Discussion A meta-analysis by Greenlee and colleagues found that anterior open bite is best treated with a combination of surgical measures and orthodontic treatment.1 In the past, an interincisal gap of more than 5mm was extremely difficult to close with orthodontics alone.9 Orthognathic surgery was deemed essential to correct skeletal discrepancies, particularly in adults. Such treatment has provided relatively stable results, as confirmed by a positive overlap of the incisors.24 In a Class II case with anterior open bite, however, mandibular ramus osteotomy alone fails to provide adequate postoperative stability for bite closure.5 Studies have supported the belief that the greater postsurgical stability seen in Class III cases is related to a postural relaxation of the mastication and hyoid muscles associated with mandibular backward repositioning.5,25 The relative instability of Class II correction might be explained by postsurgical condylar resorption and relapse, which could cause shortening of the mandible after mandibular advancement and would also reestablish positive overjet.24 Ding and colleagues observed that the postsurgical stability of anterior open-bite closure is largely dependent on the natural extrusion of anterior teeth to accommodate skeletal relapse.26 Since patients often present with two occlusal planes, incisal elongation tends to occur during the leveling and finishing phases of surgicalorthodontic treatment.9 This incisor eruption—a dental compensation to maintain the overbite relationship—is not only an esthetic concern, but may also conceal the true extent of skeletal relapse.5,24 In a comparative study of TADs and orthognathic surgery, Kuroda and colleagues found that the use of skeletal anchorage could prevent incisor elongation.9 The advent of TADs has extended open-bite treatment to younger, growing patients. Studies have indicated good stability of anterior open-bite closure with this technique, which avoids the relapse and root resorption associated with incisor extrusion. The open-bite closure is instead achieved by molar intrusion, inducing a counter-

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clockwise autorotation of the mandible that reduces anterior facial height 9 and advances the chin to correct a retrognathic mandible. This is particularly advantageous when treating Class II patients because it resolves the anteroposterior intermaxillary relationship.12 The molar intrusion has also been shown to retard posterior vertical dentoalveolar development,14 which makes TADs the optimal treatment for high-angle adolescent patients. Sugawara and colleagues did find about a 30% relapse of molar intrusion following openbite correction with TADs and one year of retention.27 Overcorrection of the molar intrusion might be advisable to allow for this anticipated posttreatment relapse. Continued use of the TADs with a clear retainer could also enhance long-term stability.12 Miniplates may sometimes be preferable to miniscrews in open-bite patients because they allow efficient tooth movement without the need for removal and reinstallation.9,28,29 Miniscrew placement is less invasive and uncomfortable, but the reported stability of miniscrews is lower than that of miniplates.9,29 Both devices have the potential of causing inflammation in the surrounding tissues if hygiene is inadequate.

Conclusion The choice between orthognathic surgery and TADs is particularly difficult in borderline anterior open-bite cases, including late adolescent and elderly patients. The costs and benefits of each procedure should be evaluated before selecting a treatment approach. When considering orthognathic surgery, the clinician should recognize the possibility of incisal elongation. On the other hand, there is a lack of long-term data confirming the stability of molar intrusion with TADs—although the results of our case remained stable for at least two years. More research is needed to determine the relative effectiveness of these treatment modalities. ACKNOWLEDGMENT: We thank Ms. Melina Ghods and Dr. Kirsten Linaker for their help with the literature review.

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REFERENCES 1. Greenlee, G.M.; Huang, G.J.; Chen, S.S.; Chen, J.; Koepsell, T.; and Hujoel, P.: Stability of treatment for anterior open-bite malocclusion: A meta-analysis, Am. J. Orthod. 139:154-169, 2011. 2. Reichert, I.; Figel, P.; and Winchester, L.: Orthodontic treatment of anterior open bite: A review article—is surgery always necessary? Oral Maxillofac. Surg. 18:271-277, 2014. 3. Park, J.H.; Tai, K.; Ikeda, M.; and Kim, D.A.: Anterior open bite and Class II treatment with mandibular incisor extraction and temporary skeletal anchorage devices, J. World Fed. Orthod. 1:e121-e131, 2012. 4. Espeland, L.; Dowling, P.A.; Mobarak, K.A.; and Stenvik, A.: Three-year stability of open-bite correction by 1-piece maxillary osteotomy, Am. J. Orthod. 134:60-66, 2008. 5. Maia, F.A.; Janson, G.; Barros, S.E.; Maia, N.G.; Chiqueto, K.; and Nakamura, A.Y.: Long-term stability of surgical-orthodontic open-bite correction, Am. J. Orthod. 138:254e1-254e10, 2010. 6. Park, H.S.; Kwon, O.W.; and Sung, J.H.: Nonextraction treatment of an open bite with microscrew implant anchorage, Am. J. Orthod. 130:391-402, 2006. 7. Solano-Hernández, B.; Antonarakis, G.S.; Scolozzi, P.; and Killiaridis, S.: Combined orthodontic and orthognathic surgical treatment for the correction of skeletal anterior open-bite malocclusion: A systematic review on vertical stability, J. Oral Maxillofac. Surg. 71:98-109, 2013. 8. Baumgaertel, S.: Temporary skeletal anchorage devices: The case for miniscrews, Am. J. Orthod. 145:558-564, 2014. 9. Kuroda, S.; Sakai, Y.; Tamamura, N.; Deguchi, T.; and TakanoYamamoto, T.: Treatment of severe anterior open bite with skeletal anchorage in adults: Comparison with orthognathic surgery outcomes, Am. J. Orthod. 132:599-605, 2007. 10. Park, J.H.; Tai, K.; Takagi, M.; Miyajima, K.; Kojima, Y.; and Joo, B.H.: Esthetic orthodontic treatment with a double J retractor and temporary anchorage devices, Am. J. Orthod. 141:796805, 2012. 11. Tai, K.; Park, J.H.; Tatamiya, M.; and Kojima, Y.: Distal movement of the mandibular dentition with temporary skeletal anchorage devices to correct a Class III malocclusion, Am. J. Orthod. 144:715-725, 2013. 12. Baek, M.S.; Choi, Y.J.; Yu, H.S.; Lee, K.J.; Kwak. J.; and Park, Y.C.: Long-term stability of anterior open-bite treatment by intrusion of maxillary posterior teeth, Am. J. Orthod. 138:396e1396e9, 2010. 13. Sherwood, K.H.; Burch, J.G.; and Thompson, W.J.: Closing anterior open bites by intruding molars with titanium miniplate anchorage, Am. J. Orthod. 122:593-600, 2002. 14. Cousley, R.R.: Molar intrusion in the management of anterior openbite and “high angle” Class II malocclusions, J. Orthod. 41:S39-S46, 2014.

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15. Peng, C.L.; Jost-Brinkmann, P.G.; Yoshida, N.; Chou, H.H.; and Lin, C.T.: Comparison of tongue functions between mature and tongue-thrust swallowing—an ultrasound investigation, Am. J. Orthod. 125:562-570, 2004. 16. Jacobson, A.: The “Wits” appraisal of jaw disharmony, Am. J. Orthod. 124:470-479, 2003. 17. Kim, Y.H.; Han, U.K.; Lim, D.D.; and Serraon, M.L.: Stability of anterior openbite correction with multiloop edgewise archwire therapy: A cephalometric follow-up study, Am. J. Orthod. 118:43-54, 2000. 18. Kim, Y.H.: Anterior openbite and its treatment with multiloop edgewise archwire, Angle Orthod. 57:290-321, 1987. 19. Küçükkeles, N.; Acar, A.; Demirkaya, A.A.; Evrenol, B.; and Enacar, A.: Cephalometric evaluation of open bite treatment with NiTi arch wires and anterior elastics, Am. J. Orthod. 116:555-562, 1999. 20. Vanden Bulcke, M.M.; Burstone, C.J.; Sachdeva, R.C.; and Dermaut, L.R.: Location of the centers of resistance for anterior teeth during retraction using the laser reflection technique, Am. J. Orthod. 91:375-384, 1987. 21. Hong, R.K.; Heo, J.M.; and Ha, Y.K.: Lever-arm and miniimplant system for anterior torque control during retraction in lingual orthodontic treatment, Angle Orthod. 75:129-141, 2005. 22. Tai, K.; Park, J.H.; Tanino, M.; and Ikeda, K.: Bimaxillary dentoalveolar protrusion treated with lingual appliances and temporary anchorage devices, J. Clin. Orthod. 46:739-746, 2012. 23. Tai, K. and Park, J.H.: Modified lingual retractor as an esthetic treatment option, J. Clin. Orthod. 49:53-61, 2015. 24. Proffit, W.R.; Bailey, L.J.; Phillips, C.; and Turvey, T.A.: Longterm stability of surgical open-bite correction by Le Fort I osteotomy, Angle Orthod. 70:112-117, 2000. 25. Ito, G.; Koh, M.; Fujita, T.; Shirakura, M.; Ueda, H.; and Tanne, K.: Factors related to stability following the surgical correction of skeletal open bite, Aust. Orthod. J. 30:61-66, 2014. 26. Ding, Y.; Xu, T.M.; Lohrmann, B.; Gellrich, N.C.; and Schwestka-Polly, R.: Stability following combined orthodonticsurgical treatment for skeletal anterior open bite—a cephalometric 15-year follow-up study, J. Orofac. Orthop. 68:245-256, 2007. 27. Sugawara, J.; Baik, U.B.; Umemori, M.; Takahashi, I.; Nagasaka, H.; Kawamura, H.; and Mitani, H.: Treatment and posttreatment dentoalveolar changes following intrusion of mandibular molars with application of a skeletal anchorage system (SAS) for open bite correction, Int. J. Adult Orthod. Orthog. Surg. 17:243-253, 2002. 28. Sugawara, J. and Nishimura, M.: Minibone plates: The skeletal anchorage system, Semin. Orthod. 11:47-56, 2005. 29. Park, J.H.; Tai, K.; and Takagi, M.: Open-bite treatment using maxillary and mandibular miniplates, J. Clin. Orthod. 49:398408, 2015.

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