Labialbow Inverted

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57JOURNAL OF INDIAN SOCIETY OF PEDODONTICS AND PREVENTIVE DENTISTRY| Jan - Mar 2011 | Issue 1 | Vol 29 |

Negi KS, Sharma KR1

Departments of Orthodontics and Dentofacial Orthopedics,1Pedodontics and Preventive Dentistry, HP Government Dental

College and Hospital, Shimla, Himachal Pradesh, India

Correspondence:Dr. Kehar S Negi, Department of Orthodontics and

Dentofacial Orthopedics, HP Government Dental College and

Hospital, Shimla, Himachal Pradesh, India.

E-mail: [email protected]

Introduction

Mesioclusion is an anteroposterior dentoalveolarrelationship characterized by a more anteriorposition of the mandibular dentition relative to themaxillary dentition. Characteristics of skeletal ClassIII malocclusion have been well documented and

summarized as follows: Skeletal components withunderdeveloped maxilla, overdeveloped mandible, or acombination of both; dentoalveolar components withproclined maxillary incisors and retroclined mandibularincisors to achieve dentoalveolar compensation.[1,2]

The relative prominence of the mandibular dentitionmay not be related to differential amounts of jawgrowth, but the apparent imbalance in jaw size isconsidered to be essentially the result of a mesial

thrust of the mandible. This malocclusion has beentermed pseudo-mesioclusion, apparent Class III,[3]

pseudoprognathism,[4,5]pseudo Class III, postural ClassIII,[6,7]and functional Class III.[8]

Moyers suggested pseudo Class III malocclusionas a positional mal-relationship with an acquiredneuromuscular reflex.[3]Pseudo Class III malocclusionhas been identified with anterior crossbite as a resultof mandibular displacement.[9,10] Premature contact

between the maxillary and mandibular incisors resultsin forward displacement of the mandible in pseudoClass III malocclusion; this displacement disengages theincisors and permits further closure into the position inwhich the posterior teeth occluded.[10,11]Several reportsattributed the incisor interference to the retroclinedupper incisors and proclined lower incisors in pseudoClass III malocclusion.[3-10,12,13]

Comparison of extra-oral photos revealed that the

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DOI:

10.4103/0970-4388.79943

PMID:

21521921

Treatment of pseudo Class III malocclusion

by modified Hawleys appliance with invertedlabial bow

Abstract

Pseudo Class III malocclusion is characterized by an anterior

crossbite with functional forward mandibular displacement.

Various appliances have been devised for early treatment ofa pseudo Class III. The aim of this article is to highlight the

method of construction and use a simple removable appliance

termed as Modified Hawleys appliance with inverted labial

bow to treat psuedo class III malocclusion in the mixed

dentition period. It also emphasizes the importance of

differentiating between true Class III and pseudo Class III. This

appliance in this type of malocclusion enabled the correction

of a dental malocclusion in a few months and therapeutic

stability of a mesially positioned mandible encouraging

favorable skeletal growth.

Key words

Hawleys appliance with inverted labial bow, psuedo Class

III malocclusion


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Negi and Sharma: Psuedo class-III malocclusion and its simple management

58 JOURNAL OF INDIAN SOCIETY OF PEDODONTICS AND PREVENTIVE DENTISTRY| Jan - Mar 2011 | Issue 1 | Vol 29 |

profile of pseudo Class III malocclusion appearednormal at centric relation (CR) and slightly concave athabitual occlusion (HO); moreover, molar relationshipwas Class I at CR and Class III at HO. [10,12]PseudoClass III malocclusion is characterized by certainmorphologic, dental, and skeletal characteristics:retrusive upper lip, decreased midface length,

retroclined upper incisors, and increased maxillary-mandibular difference.[14]

Different etiological factors are suggested in

pseudo Class III malocclusion[8]

Dental factors

Ectopic eruption of maxillary central incisors Premature loss of deciduous molars

Functional factors

Anomalies in tongue position

Neuromuscular features Nasorespiratory or airway problems

Skeletal factors

Minor transverse maxillary discrepancy

Management of pseudo Class III malocclusionThe pseudo Class III malocclusion involves bothpermanent teeth and the deciduous dentition. Becausea malocclusion may be regarded as an aestheticproblem, parents often inquire whether a therapy isrequired. It is difficult to justify the lack of attention

given to the timing of treatment of pseudo ClassIII malocclusion, which remains controversial.[15]Some clinicians believed that in many patients, itwas best to allow the eruption of permanent teethbefore initiating orthodontic treatment. In this way, arelatively straightforward manner of treatment withina predictable duration could be provided for patients.However, delaying the treatment until permanentdentition errupts may cause loss of space required foreruption of the canines.[3,10,13]Some practitioners preferto wait for the permanent maxillary incisors to eruptbefore initiating therapy due to the natural tendency

of teeth to erupt in a lingual position during dentalarch development. Occasionally, functional deciduousanterior crossbites correct themselves spontaneously.White has suggested intervention in cases of pseudoClass III malocclusion in mixed dentition when themaxillary and mandibular incisors have erupted.[16]This allows permanent teeth to erupt in a betterposition and also improves dental aesthetics.

In general terms, the goal of interceptive orthodontics

is to prevent an existing problem from worsening.Specifically, for pseudo Class III, the goals of earlytreatment are to correct the anterior displacementof the mandible before the eruption of the caninesand premolars. Anterior teeth can be guided intoClass I in the proper mandibular position, to providespace for eruption of the buccal segments as a result

of proclination of the upper incisor, and to provide anormal environment for growth of the maxilla, thuseliminating the anterior crossbite.[10,15,17]

From a therapeutic point of view, Graber[6]and otherssuggested that the mesioclusion must be examined withthe mandible guided into a retruded contact position.If the mandibular incisors approach an edge-to-edgeocclusion and then slide into anterior displacement, themalocclusion may be pseudo-mesioclusion. Conversely,a true mesioclusion is one in which the mandible cannotbe retruded and the pattern of closure is a smootharch, anteroposteriorly. Various appliances have beendevised for early treatment of a pseudo Class III, suchas removable plates with springs, fixed or removableinclined planes, functional appliances, chin-cups, andsimple fixed appliances.[9,13,18]

This case report is intended to illustrate a simple andeasy way to manage pseudo Class III by a modifiedHawleys appliance with inverted labial bow.

Case Report

A male patient aged 9 years and 6 months, presented withchief complaint of the lower anterior teeth overlappingthe upper teeth; his parents were also concerned becauseof his abnormal facial profile. On clinical examination, aretruded upper lip with prominent lower lip was noted,giving an appearance of midface deficient as seen inclass III malocclusion. There was a mesial step molarrelationship in centric occlusion with the incisors incrossbite. The dental relationship suggested retroclinedupper central incisors, with mild proclination of lowerincisors [Figure 1]. The incisors were in end-to-end

relationship with posterior open bite when the mandibleguided in centric relation. Clinical examination revealedthat the displacement occurred due to a prematurecontact between upper and lower incisors. Therefore,the diagnosis made was a pseudo Class III malocclusioncharacterized by anterior crossbite and functionalmandibular shift in centric occlusion.

Appliance designIn order to construct a modified Hawleys appliance,


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register the bite by guiding the mandible distallyin an edge-to-edge incisors relation. Subsequently,transfer the bite in the working model and articulateit in the hinge articulator. After mounting the upperand lower casts remove the construction bite andfabricate an inverted labial bow [Figure 2] andAdams clasp with 0.036stainless steel wire. Further,stabilize the inverted labial bow by using wax and

Figure 3: Intra-oral photograph showing the position of mandible

guided by the appliance at the time of delivery

Figure 2: The construction of modied Hawleys appliance withinverted labial bow

Figure 4:Intra-oral photograph showing patient closing mandible inedge-to-edge relation one week after use of the appliance

Figure 1:Extra- and intra-oral photographs showing class III prolewith anterior crossbite

Figure 5:Extra- and intra-oral photographs showing the normal proleand occlusion after one month use of the appliance


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60 JOURNAL OF INDIAN SOCIETY OF PEDODONTICS AND PREVENTIVE DENTISTRY| Jan - Mar 2011 | Issue 1 | Vol 29 |

construct the acrylic plate as the Hawleys appliance[Figure 2].

Treatment objectives To eliminate CR-CO discrepancy and anterior

crossbite To correct Class III and establish Class I canine

relationship To achieve normal overjet, and reduce deep bite

Treatment progressBite was registered by guiding the mandible distally inincisor edge-to-edge relation for mounting the upperand lower cast in the laboratory. Modified Hawleysappliance was constructed with inverted labial bow.The appliance was delivered with instruction touse it at night for a week and return for follow-up[Figure 3]. After a week, the patient was comfortable

and functional shift of mandible occurred in the edge-to-edge incisor relation while closing [Figure 4].The patient then was asked to use the appliancecontinuously, except while eating and report after threeweeks. With regard to continuous use of appliancefor one month, the patient was able to comfortablyclose the mandible in centric occlusion with positiveoverbite. Also, there was almost intercuspation inposterior occlusion, with normal lip relation andprofile [Figure 5]. The appliance was discontinuedafter two months when normal occlusion was achievedin centric occlusal relation without the appliance and

the patient was advised to use the appliance only atnight as a retainer for six months.

Discussion

The various treatments suggested in the literature forcorrection of anterior crossbite include several differentappliances, both fixed and/or removable with heavyintermittent forces (inclined bite plane, tongue blade)or light-continuous forces (removable appliance withauxiliary springs). Other alternative therapies that may

correct skeletal problems in young patients have beenshown to be effective, with significant changes in thecraniofacial complex, including the use of protractionheadgear, chincap, and Frankel III.[19-22]Tsai suggeststhe use of rapid palatal expansion and standardedgewise appliance to resolve an anterior crossbite ina 7-year-old boy.[23]

Rabie and Gu have described a simple method forearly treatment of pseudo Class III malocclusion

in the mixed dentition by using fixed appliance.Proclination of the upper incisors and/or retroclinationof the lower incisors contribute to the correctionof anterior crossbite and elimination of mandibulardisplacement.[24]Early treatment also permits us togain space for canine eruption. The therapeutic use ofa modified Hawleys appliance with inverted labial bow

is suggested in this case report with anterior crossbitein mixed dentition as the simplest way of managinganterior crossbite as compared to other conventionalappliances mentioned in the literature.

Conclusion

Modified Hawleys appliance with inverted labial bowis easy to construct and patient-friendly applianceto correct anterior crossbite in Psuedo class-IIImalocclusion.

Early treatment of Psuedo class III malocclusion helpsin: Elimination of mandibular displacement, thus

allowing the permanent dentition to be guided intoClass I at proper mandibular position

Creation of space for eruption of canines andpremolars

Elimination of traumatic occlusion.

References

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Source of Support:Nil, Conict of Interest:Nil

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