Orthodontic treatment for a patient with ... · space-closure option.9 Finally, there is a risk of space reopening in any space-closure treatment. In this patient, because of the

CASE REPORT

Orthodontic treatment for a patient withhypodontia involving the maxillary lateral incisors

Saud A. Al-AneziKuwait City, Kuwait

SpeciaCenteThe aucts oReprinSpeciaKuwaSubm0889-Copyrdoi:10

690

Developmental absence of maxillary lateral incisors is not uncommon in orthodontic patients. Treatmentdepends on a number of factors, including skeletal pattern, type of malocclusion, overjet, and the shape andcolor of the canines. Management can be broadly divided into space closure, space opening or redistribution,and prosthetic replacement. The purpose of this article was to report the treatment of a girl with an Angle ClassI malocclusion with missing maxillary lateral incisors and severe crowding in the mandibular labial segment.Treatment included preadjusted fixed appliances, extraction of themandibular first premolars, and space closureof the maxillary labial segment space with the canines substituted for the maxillary lateral incisors. (Am J OrthodDentofacial Orthop 2011;139:690-7)

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Hypodontia is the developmental absence of atleast 1 tooth.1 The incidence of missing maxil-lary lateral incisors is 1% to 2% in white popula-

tions.2 The etiology of hypodontia can be geneticallydetermined and arises as a familial condition. The condi-tion is more common bilaterally than unilaterally andcan be associated with impacted maxillary canines.This condition causes several problems, including un-sightly spacing between the anterior teeth, and driftingand rotation of the central incisors and the canines. Inunilateral cases, these effects are asymmetric and can re-sult in a midline shift. Furthermore, dental health prob-lems might arise because of food impaction as a result oftipped teeth. A suspected absence of the maxillary per-manent lateral incisor should be confirmed radiograph-ically if the tooth has failed to erupt by the age of 9 years,or within 6 months of the contralateral tooth.3

The management of missing maxillary lateral incisorsoften needs a multidisciplinary approach and can bebroadly divided into space closure, space opening, andspace redistribution. A number of factors should beconsidered in the management of such patients.4 Theseinclude patient factors: age, medical history, motivation,and attitude toward orthodontic treatment. Other

list orthodontist, Orthodontics Department, Bneid Al-Gar Specialty Dentalr, Ministry of Health, Kuwait.uthors report no commercial, proprietary, or financial interest in the prod-r companies described in this article.t requests to : Saud A. Al-Anezi, Orthodontics Department, Bneid Al-Garlty Dental Center, Ministry of Health, PO Box 11610, Dasma 35156,it; e-mail, [email protected], June 2009; revised, September 2009; accepted, October 2009.5406/$36.00ight � 2011 by the American Association of Orthodontists..1016/j.ajodo.2009.10.042

factors include skeletal pattern, type of malocclusion,number of missing teeth, size, shape, and the gingivalmargin of the maxillary canines. In this case report, anadolescent girl complained of the appearance of hermaxillary anterior teeth because of developmentally ab-sent lateral incisors and crowding in themandibular arch.

DIAGNOSIS AND ETIOLOGY

This girl, aged 14.6 years, had an Angle Class _ mal-occlusion on amild Class __ skeletal pattern with reducedFrankfort mandibular plane angle and lower anteriorface height. There was no facial asymmetry, and thelips were competent with a low smile line (Fig 1). Inthe intraoral assessment, her oral hygiene was fair butneeded improvement before orthodontic treatment.The erupted teeth were as follows.

Both maxillary and mandibular left first molars werehypoplastic but not carious. Fissure sealants were pres-ent occlusally in all first molars. From the history andclinical examination, these teeth did not cause any prob-lem to the patient (eg, sensitivity), and the long-termprognosis was good. The maxillary arch had spacing,whereas the mandibular arch was severely crowded.Overjet was 5.5 mm, and overbite was deep with palatalimpingement. The molar relationship was Class I on bothsides, and the incisor relationship was Class II Division 2(Fig 2). The maxillary canines were in crossbite. Further-more, the maxillary left central incisor and the maxillaryright second premolar were rotated; these might causesome concern in terms of stability and risk of relapse.

Fig 1. Pretreatment clinical photographs.

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The mandibular left second premolar was partially erup-ted. In addition, space analysis showed that the spacerequirement in the mandibular arch was 14 mm.

The dental panoramic tomogram confirmed the pres-ence of all permanent teeth except the maxillary lateralincisors and the third molars. Teeth yet to erupt werethe maxillary and mandibular second molars and themandibular third molars (Fig 3). Root length and mor-phology appeared normal. In the cephalometric assess-ment (Fig 4 and Table). The ANB value was 3�, whichsuggested a Class _ skeletal pattern. However, by apply-ing the Eastman correction (SN/Max 10�), the correctedANB was 5�, which indicated a mild Class __ skeletal pat-tern.5 The mandibular incisor inclination was retroclinedat 80�. The maxillary left central incisor was proclined at118�, and the maxillary right central incisor appearedretroclined. The lower anterior face height was reduced,

American Journal of Orthodontics and Dentofacial Orthoped

and the mandibular incisor to the APo line was withinnormal limits. The lower lip was positioned posteriorlyto the E-line.

The malocclusion was complicated by the develop-mentally absent maxillary lateral incisors, increasedand complete overbite, severe crowding in the mandib-ular arch and the crossbite involving the maxillary ca-nines. The genetically inherited skeletal pattern andthe reduced vertical proportions contributed to the mal-occlusion. In addition, the high lower lip line contributedto the retroclination of the maxillary right central incisor.

TREATMENT OBJECTIVES

The treatment objectives included (1) accept the pa-tient’s profile, (2) relieve the crowding in the mandibularlabial segment, (3) level and align, (4) reduce the over-bite, (5) reduce the overjet and correct the crossbite

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Fig 2. Pretreatment models.

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involving the maxillary canines, (6) close the maxillaryspacing, (7) substitute the maxillary canines as lateralincisors, and (8) retain.

The decision to close the space in the maxillary labialsegment was based on the fact that the patient hada mild Class __ skeletal pattern with a slightly increasedoverjet. In addition, the shape and the color of the max-illary canines were considered favorable in terms of es-thetics. Restorative treatment was planned to reshapethe maxillary canines and camouflage their appearance.The severity of crowding in the mandibular labial seg-ment indicated the necessity to extract the mandibularleft and right first premolars. The patient was treatedwith a fixed appliance with a 0.022-in slot McLaughlin,Bennett, Trevisi (MBT) prescription.6 The maxillaryfixed retainer was chosen to minimize the risk of relapseof the severely rotated maxillary left central incisor. Inaddition, the patient was provided with maxillary andmandibular Essix retainers (DENTSPLY Limited, Surrey,United Kingdom). from the first molar to the first molarto wear at night only.

TREATMENT ALTERNATIVES

As an alternative, space opening in the maxillary archand replacement of the maxillary lateral incisors with im-plants might have been considered. However, the

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severity of the mandibular arch crowding necessitatedthe extraction of the mandibular premolars. As a conse-quence, there was a need to compensate for the extrac-tions in the mandibular arch with extractions in themaxillary arch, because the malocclusion was essentiallyClass I. Because the maxillary lateral incisors were devel-opmentally absent, further extractions in the maxillaryarch were not required. In addition, the color and mor-phology of the maxillary canines were encouraging touse them as lateral incisors.

TREATMENT PROGRESS

The treatment progressed well without major compli-cations. The patient was cooperative, and her oral hy-giene improved as the treatment progressed. Overbitereduction started slowly at the beginning of treatment(Fig 5). The banding of the mandibular second molarshelped in controlling the overbite. The use of Class __ in-termaxillary traction helped to reduce the overjet andclose the maxillary space. This also had the effect of ex-truding the mandibular molars and ultimately helpedwith the overbite reduction. A reverse curve of Speewas placed in the mandibular archwire to further reducethe overbite.7 This was necessary before the space clo-sure phase of treatment. During treatment, space closurein the mandibular arch progressed well. However, space

Journal of Orthodontics and Dentofacial Orthopedics

Fig 4. Pretreatment cephalometric tracing.

Fig 3. Pretreatment dental panoramic tomograph and lat-eral cephalometirc radiograph.

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closure in the mandibular right quadrant was slow. Ra-diographic assessment showed that the roots of themandibular right canine and the second premolar weretoo close together. This was rectified with bracket repo-sitioning and artistic bends in the archwire as the spacewas closed.

TREATMENT RESULTS

The duration of active treatment was 23 months, andthe treatment objectives were achieved. The patient’sprofile was maintained (Fig 6). At the end of treatment,the maxillary labial segment space was closed by move-ment of the canines mesially. The incisor relationshipwas Class I. The overjet at the end of treatment was 2mm. The mandibular crowding was relieved, and themandibular incisors were aligned (Fig 7). The overbitewas dramatically reduced. The bilateral crossbites in-volving the mandibular canines were eliminated, andthe dental midlines were coincident.

American Journal of Orthodontics and Dentofacial Orthoped

DISCUSSION

The decision to close the space was based on a num-ber of factors. Firstly, the patient had a Class II skeletalpattern; hence, space opening to place implants mightworsen her profile. Furthermore, there was a slight in-crease in the overjet; therefore, space closure wouldalso lead to a reduction in the overjet. The smile linewas low, so that the discrepancies in the gingival mar-gins of the canines and the central incisors would notbe apparent. Another important advantage of space clo-sure was that the gingival tissue and interdental papillaewould change in synchrony with the patient’s own teethover her lifetime.8

However, there are potential disadvantages with thespace-closure approach. Moving the canine mesiallynext to the central incisor might not be estheticallypleasing, since the cusps are prominent and these teethare naturally darker than the lateral incisor. In this pa-tient, the morphology and the color of the maxillary ca-nines were encouraging. A restorative camouflageconsisting of careful grinding, composite buildup, andbleaching was an integral part of the treatment plan.Nonetheless, the patient was satisfied with the outcomeof the grinding and reshaping of the canines without theneed for composite buildup or bleaching.

Another potential disadvantage is that placing thefirst premolar in the position previously occupied bythe canine might result in heavy occlusal forces, since

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Fig 5. Progress intraoral photographs showing the maxillary and mandibular 0.0203 .0.020-in nickel-titanium archwires.

Table. Cephalometric analysis

Variable Pretreatment Normal* Predebond Overall changeSNA 86� 82� 6 3� 85� �1�

SNB 83� 79� 6 3� 82� �1�

ANB 3� 3� 6 1� 3� 0Maxillary incisor to maxillary plane angle 118� 108� 6 5� 113� �5�

Mandibular incisor to mandibular plane angle 80� 92� 6 5� 90� �10�

Interincisal angle 142� 133� 6 10� 130� �12�

Maxillary-mandibular planes angle 20� 27� 6 5� 23� 3�

Face height ratio 52% 55% 54% 2%Mandibular incisor to APo line �2 mm 0–2 mm 1 mm 3 mmLower lip to Ricketts’ E-plane �4 mm �2 mm �1 mm 3 mm

SNA, Sella–nasion–A-point; SNB, sella–nasion–B-point; ANB, A-point–nasion–B-point; APo, A-point–pogonion.*Normal values for white subjects taken from Houston et al.13

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canine-protected occlusion is not possible. The roots ofthe first premolars are thinner and smaller; therefore,there is a concern of potential damage to the periodontalhealth. However, a long-term study failed to demon-strate this effect, and some studies are in favor of thespace-closure option.9

Finally, there is a risk of space reopening in anyspace-closure treatment. In this patient, because of therotated maxillary left central incisor, there was evena greater risk. Therefore, the decision was made to placea fixed retainer consisting of a braided stainless steel(0.0175 in) wire from canine to canine to minimize therisk of relapse. In the mandibular arch, it was necessaryto extract the first premolars to relieve the severe crowd-ing in the incisor region and to flatten the occlusal plane.

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In addition, because the decision was made to close thespace in the maxillary labial segment, extraction in themandibular arch was indicated to maintain the Class Ibuccal segment relationship.

During treatment, both the SNA and SNB values werereduced by 1�; the ANB value remained unchanged.When the Eastman correction was applied, the correctedANB value was 5�. The maxillary and mandibular planeangles and the lower anterior face height increasedslightly during treatment (Fig 8). This reflected the smallamount of vertical growth as seen on the superimposi-tion on the anterior cranial base. Toward the end oftreatment, the mandibular incisors had proclined by10� to 90�. The maxillary left central incisor was retro-clined by 5� as a result of the overjet reduction. The

Journal of Orthodontics and Dentofacial Orthopedics

Fig 6. Posttreatment clinical photographs.

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interincisal angle was also reduced to an average valueof 130� (Fig 9). The reduction in the interincisal angleand the normal edge centroid relationship should helpto maintain the overbite reduction.10

The overall superimposition demonstrated thatgrowth had occurred, which was in a downward and for-ward direction (Fig 10). The maxillary superimpositionregistered on the anterior surface of the zygomatic pro-cess of the maxilla showed a downward and slightly for-ward direction of movement. The maxillary incisors wereextruded slightly from the Class __ intermaxillary trac-tion, and the roots were torqued palatally. The maxillarymolars were extruded slightly and remained relativelyunchanged in the anteroposterior direction.

Because a preadjusted fixed appliance with an MBTprescription was used, it allowed the opportunity to ap-ply subtle tooth movements to improve the esthetics.

American Journal of Orthodontics and Dentofacial Orthoped

The maxillary canine brackets were inverted to givea positive canine torque to reduce the canine eminence.This was supplemented with additional palatal root tor-que in the maxillary archwire. Moreover, the maxillaryfirst premolars were rotated mesially, and buccal roottorque applied to prevent any nonworking-side interfer-ences on excursive movements of the mandible.

The patient was extremely happy with the outcome,and the appliances were removed. The maxillary fixed re-tainer was bonded, and the patient was provided withmaxillary and mandibular Essix retainers from the firstmolar to the first molar to wear during the night. Thereare claims in the literature that Essix retainers are moreeffective in maintaining the labial segments and arecost-effective, and patients preferred them over Hawleyretainers.11,12 Arrangements have been made to reviewthe patient regularly during the retention phase of

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Fig 7. Posttreatment models.

Fig 8. Predebond lateral cephalometric radiograph.

Fig 9. Predebond cephalometric analysis.

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Fig 10. Overall superimposition of pretreatment (black)and predebond (red) cephalometric radiographs, regis-tered on the stable structures in the anterior cranial base.

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treatment. Furthermore, she was referred to her generaldental practitioner for regular checkup appointments.

CONCLUSIONS

An adolescent girl came with a Class I malocclusioncomplicated by developmentally absent maxillary lateralincisors and severe crowding in the mandibular labialsegment. The treatment involved the use of preadjustedfixed appliances, extraction of the mandibular right andleft first premolars, closing of the maxillary labial

American Journal of Orthodontics and Dentofacial Orthoped

segment space, and canine substitutions for the maxil-lary lateral incisors.

I thank the patient, her family, and all the staff in theorthodontics department at the Royal United Hospital,Bath, United Kingdom.

REFERENCES

1. Goodman JR, Jones SP, Hobkirk JA, King PA. Hypodontia: clinicalfeatures and the management of mild to moderate hypodontia.Dent Update 1994;21:381–4.

2. Zilberman Y, Cohen B, Becker A. Familial trends in palatal canines,anomalous lateral incisors, and related phenomena. Eur J Orthod1990;12:135-9.

3. Isaacson KG, Thom AR, Horner K, Whaites E. Orthodontic radio-graphs: guidelines. London, United Kingdom: British OrthodonticSociety; 2008.

4. Carter NE, Gillgrass TJ, Hobson RS, Jepson N, Meechan JG,Nohl FS, et al. The interdisciplinary management of hypodontia:orthodontics. Br Dent J 2003;194:361-6.

5. Mills JR. The application and importance of cephalometry inorthodontic treatment. Orthodontist 1970;2:32-47.

6. Bennett JC, McLaughlin RP. Orthodontic management of thedentition with the preadjusted appliance. St Louis: Mosby; 2001.

7. Parker CD, Nanda RS, Currier GF. Skeletal and dental changes as-sociated with the treatment of deep overbite malocclusion. Am JOrthod Dentofacial Orthop 1995;107:382-93.

8. Rosa M, Zachrisson BU. Integrating esthetic dentistry and spaceclosure in patients missing maxillary lateral incisors. J Clin Orthod2001;35:221-34.

9. Robertsson S, Mohlin B. The congenitally missing upper lateralincisor. A retrospective study of orthodontic space closure versusrestorative treatment. Eur J Orthod 2000;22:697-710.

10. Houston WJB. Incisor edge-centroid relationships and overbitedepth. Eur J Orthod 1989;11:139-43.

11. Rowland H, Hichens L, Williams A, Hills D, Killingback N, Ewings P,et al. The effectiveness of Hawley and vacuum-formed retainers:a single-center randomized controlled trial. Am J Orthod Dentofa-cial Orthop 2007;132:730-7.

12. Hichens L, Rowland H, Williams A, Hollinghurst E, Ewings P,Clark S, et al. Cost-effectiveness and patient satisfaction:Hawley and vacuum-formed retainers. Eur J Orthod 2007;29:372-8.

13. Houston WJ, Stephens CD, Tulley WJ. A textbook of orthodontics.Wright, Oxford: United Kingdom; 1992.

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