CLINICIAN’S CORNER

Multiloop edgewise archwire in the treatment ofa patient with an anterior open bite and a longface

Gerson Luiz Ulema Ribeiro,a Saulo Regis, Jr,b Tais de Morais Alves da Cunha,b Marcos Adriano Sabatoski,b

Odilon Guariza-Filho,c and Orlando Motohiro Tanakad

Florianopolis, Santa Catarina, and Curitiba, Parana, Brazil

An adolescent girl with an Angle Class III malocclusion, excessive lower facial height, and anterior open bitesought nonsurgical treatment. She was treated with a multiloop edgewise archwire (MEAW). In associationwith a chincup, MEAW mechanics allowed the successful correction of the anterior open bite and the molarrelationship, without major alterations of the patient’s profile. Combined orthodontic and surgical treatmentshould be considered for patients with skeletal anterior open-bite malocclusion. For patients who do notwant surgery, however, MEAW treatment is an alternative that can have excellent results. (Am J OrthodDentofacial Orthop 2010;138:89-95)

An anterior open bite malocclusion is a difficultproblem in orthodontic treatment.1,2 Becauseof separate occlusal planes for the maxillary

and mandibular dentitions, the open bite would beconfigured by the anterior divergence of these planes,instead of the overlap seen in normal occlusion.3 Thismalocclusion is usually associated with internal de-rangement of the temporomandibular joint.4

Most patients with anterior open bites have botha dentoalveolar component and increased skeletal verti-cal dimension.5,6 The true skeletal open-bite patientwould require a combination of orthodontic treatmentand orthognathic surgery to achieve a stable occlusion,acceptable esthetics, and improved function.7 However,surgery can be too expensive for some patients, andothers refuse to consider such an invasive intervention.8

The orthodontist’s only choice will be to deny treatmentor try to resolve as much of the malocclusion as possiblewith orthodontic treatment alone.

aAdjunct professor, Graduate Dentistry Program in orthodontics, Federal

University of Santa Catarina, Florianopolis, Santa Catarina, Brazil.bPostgraduate student, Dentistry Graduate Program in orthodontics, Pontifical

Catholic University of Parana, Curitiba, Parana, Brazil.cAssociate professor, Graduate Dentistry Program in orthodontics, Pontifical

Catholic University of Parana, Curitiba, Parana, Brazil.dProfessor, Graduate Dentistry Program in orthodontics, Pontifical Catholic

University of Parana, Curitiba, Parana, Brazil.

The authors report no commercial, proprietary, or financial interest in the

products or companies described in this article.

Reprint requests to: Orlando Motohiro Tanaka, Pontifical Catholic University of

Parana, Graduate Dentistry Program, Orthodontics, R Imaculada Conceicao,

1155, 80215-901, Curitiba, PR, Brazil; e-mail, tanaka.o@pucpr.br.

Submitted, December 2007; revised and accepted, March 2008.

0889-5406/$36.00

Copyright � 2010 by the American Association of Orthodontists.

doi:10.1016/j.ajodo.2008.03.036

The multiloop edgewise archwire (MEAW) wasintroduced by Kim3; he had already been using it for al-most 2 decades. This technique has been successfullyapplied for treatment of severe open-bite malocclusions.The objectives of treatment include proper vertical po-sitioning of the maxillary incisors, compatible cant ofthe maxillary and mandibular occlusal planes, and up-righted inclination of the posterior teeth. The form ofthe MEAW is primarily that of an ideal edgewise arch-wire with the addition of boot loops.3 The vertical loopcomponent serves as a break between the teeth, givesflexibility to the archwire, and allows horizontal con-trol of the tooth positions.9 The horizontal componentgives more flexibility and provides vertical control. Itis 2.5 times the length of wire in ordinary archwiresand provides a 10-fold reduction in the load-deflection rate. The use of MEAW requires completionof all leveling and alignment, elimination of all poorlypositioned brackets, and constant use of vertical elas-tics on the anterior teeth. It was originally prescribedfor brackets with .018-in slots and .016 3 .022-inarchwires, allowing more flexibility for intrusiveforces.3

This article shows a successful treatment result ina growing patient with an Angle Class III subdivisionmalocclusion and an anterior open bite.

CASE REPORT

A girl, aged 14 years 8 months, was referred by herclinician to a private office after consulting 2 other or-thodontists, with the complaint of an anterior openbite. She had a pleasant profile, although there was

89

Fig 1. Pretreatment records: skeletal Class I, Angle Class III subdivision malocclusion with anterioropen bite, mandibular midline deviation, protrusion of mandibular incisors, straight profile, and min-imal maxillary incisor exposure when smiling.

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increased lower facial height and little incisor expo-sure during smiling (Fig 1). She had an Angle ClassIII subdivision malocclusion, with an anterior openbite of 3.5 mm, an overjet of 0.5 mm, and a midlinediastema. The mandibular dental midline was deviatedto the left by 1.5 mm. Cephalometric analysis showeda skeletal Class I relationship (ANB angle, 4�) anda high mandibular plane angle (FMA, 32�). The max-illary incisors to NA angle was 19�; the maxillary in-cisors to NA distance was 4 mm; the anterior inferiorteeth were protruded, with mandibular incisors to NBangle was 42�; and the mandibular incisors to NB dis-tance wa 9 mm.

Several factors have been implicated as causes of ananterior open-bite malocclusion, including inherited fa-cial form, unfavorable growth pattern, posture, suckinghabits, nasopharyngeal airway obstruction, and tongueposture and function.1 Kim3 reported that the associa-tion of an inclined occlusal plane and mesial tippingof posterior teeth might cause an anterior open bite. Insome cases, open bite is more likely to be producedby the interaction of different functional aspects andenvironmental influences with facial morphology.1

Our patient had a hyperdivergent facial profile but nohistory of sucking habits, mouth breathing, or abnormaltongue posture or swallowing.

Fig 2. High-pull chincup and edgewise fixed appliance, 0.022-in slot with 0.019 3 0.026-in stainlesssteel MEAW with gradual increase in boot-loop size. Intermaxillary elastics mechanics and finishingproduced a satisfactory intercuspation.

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The main objective of open-bite treatment in generalis to achieve ideal overbite and overjet relationships.The vertical reference for anterior teeth would be theposition of the maxillary central incisor relative to theinferior lip line.3 When treating an open-bite malocclu-sion, correction of the maxillary and mandibular occlu-sal planes and the axial inclinations of the teeth must beconsidered.1,3 Therefore, the orthodontist’s choice tointrude the molars or extrude the anterior teeth will beguided mainly by the vertical dimension of the lowerface and the esthetic features of the anterior segment.

This patient’s Angle Class III malocclusion wouldbe corrected by uprighting the mandibular posteriorteeth and using intermaxillary elastics, with Class III re-sulting on the right side. A high-pull chincup wouldneed to be worn 16 hours a day. Ideal overjet and over-bite would be achieved by extruding the maxillary and

mandibular anterior teeth, and also correcting the poste-rior tooth inclination, resulting in correction of thereverse curve of Spee in the mandibular arch. Becausethe patient had little maxillary central incisor exposureduring smiling, the anterior tooth extrusion would alsofavor a more esthetic result. Delicate control of thefacial height would be required.

Full edgewise fixed appliances with 0.022-in slotbrackets were placed. During the alignment and level-ing stages, the patient wore a vertical chincup (16 hoursa day) to prevent extrusion of the posterior teeth (Fig 2).A .019 3 .026-in stainless steel archwire, made withboot loops in all interproximal areas from the lateralincisors to the second molars, was used. On each loop,we checked lingual root torque, bilateral symmetry,and vertical-segment angulations to prevent gingival in-juries. Tip-back bends were incorporated. The curve of

Fig 3. Posttreatment records show good intercuspation, overjet, overbite, anteroposterior relation-ship, canine guidance, and root apex integrity.

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Spee in the maxillary arch was increased and reversed inthe mandible. The tip-back bends and the Spee curvesprovided intrusive forces on the maxillary and mandib-ular incisors, an effect opposed by 3/16-in elastics withvertical force placed in the canines’ mesial loops. These

elastics delivered a 50-g force with the mouth closedand 150 g with moderate mouth opening.

After bite closure and finishing, the treatment objec-tives were achieved, and the appliances were removed(Fig 3). Treatment time was 3 years. An Angle Class I

Table. Cephalometric analysis

Measurement Norm Pretreatment Posttreatment

SNA (�) 82 84 85

SNB (�) 80 80 81

ANB (�) 2 4 4

Convexity 0 11 12

Y-axis 59.9 60 60

Facial 87.8 89 89

SN-GoGn (�) 32 42 41

FMA (�) 25 32 33

IMPA (�) 90 97 83

Maxillary incisor-NA (�) 22 19 11

Maxillary incisor-NA (mm) 4 4 2

Mandibular incisor-NB (�) 25 42 27

Mandibular incisor-NB (mm) 4 9 7

1-1 130 130 136

1�A-Po 1 1 5

LS-S 0 0 0

LI-S 0 1 0

Z angle (�) 75 75 79

American Journal of Orthodontics and Dentofacial Orthopedics Ribeiro et al 93Volume 138, Number 1

molar relationship was achieved on both sides, andoverjet, anterior open bite, and mandibular midline de-viation were all corrected. As intended, the facial profilewas maintained, and the incisors’ exposure during smil-ing increased.

A slight increase of the mandibular plane angle(FMA, from 32� to 33�) was verified. The maxillaryand mandibular incisors were more upright (IMPA,from 97� to 83�). Other cephalometric changes arereported in the Table.

At the follow-up appointment 5 years after treat-ment, stability of the dental and skeletal vertical dimen-sion as well as the overjet and overbite could be seen(Fig 4).

DISCUSSION

The patient had a hyperdivergent skeletal patternand anterior open bite with some dental component, ex-cessive lower facial height, and vertical growth trend.Treatment for such patients includes managing growth.Cangialosi5 suggested that most patients with anterioropen bite have skeletal and dentoalveolar features con-tributing to the malocclusion. Not all skeletal open-bitesubjects have negative overbite.10 The distinction be-tween a skeletal and a dental open-bite malocclusionis a practical matter because there should be differentapproaches for each condition to obtain an effectiveand stable treatment result.8

Various therapeutic modalities have been proposedfor the treatment of anterior open-bite malocclusion inboth growing and nongrowing patients, depending onthe treatment objectives. Conventional orthodontic-

orthopedic treatment has been directed at inhibiting ver-tical maxillary growth with headgear, retarding mandib-ular growth with chincups, and extruding anterior teethwith vertical elastics.11,12 Some other methods that havebeen used include tongue-crib therapy for habit control,posterior bite-blocks, posterior magnets, magneticactive vertical corrector, and functional appliances.1

Orthodontic treatment of patients with skeletal openbite consists of intruding the posterior teeth or prevent-ing their further eruption with the intention to controlanterior facial height. The vertical position of the denti-tion is greatly influenced by the teeth and alveolar pro-cess and their adaptation to the jaw relationship. Thisfacilitates the correction of overbite and overjet byorthodontic movement alone.

A great challenge in treating an anterior open bite isthe control of anchorage when molar intrusion isrequired.2 Devices usually proposed are high-pull head-gear, lingual arches, functional appliances, and poste-rior bite-blocks.8 Carano et al13 primarily reported theuse of a new device for rapid molar intrusion. An effec-tive way to intrude molars is to use skeletal anchoragewith titanium screws.2,8

Kuroda et al,14 in a study comparing treatment out-comes with molar intrusion using skeletal anchorageand orthognathic surgery, demonstrated no significantdifference in both treatment results in terms of reducingfacial heights and increasing overbite.

MEAW therapy for anterior open-bite malocclusionhas been demonstrated to be effective for the treatmentof this malocclusion. Kim et al,1 evaluating its long-term stability, found no significant relapse in a 2-yearfollow-up. This mechanism was able to retract andextrude the anterior teeth and to upright the posteriorteeth.1,8 It is a good option for orthodontic treatmentof skeletal open bite, although the technique has littleor no effect on the skeletal pattern.8

There is no agreement about the ability to intrudeposterior teeth in the literature, although there are fewstudies about the effects of MEAW on the dentition.1,8

The disadvantages of the MEAW approach are therequirement of high professional skills and the greatdependence on patient compliance for treatment success.

CONCLUSIONS

Orthodontic treatment combined with surgeryshould be considered for patients with a skeletal anterioropen-bite malocclusion, but the patient’s choice must berespected. The MEAW appliance was shown to have anexcellent treatment outcome, achieving the proposedgoals, although this technique required excellent profes-sional ability.

Fig 4. Long-term stability at the 5-year follow-up, with maintenance of adequate overbite and over-jet. The third molars were extracted.

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