Anterior Crossbite Correction with a Series of Clear

Removable Appliances: A Case Reportjerd_257 149..159

JAE HYUN PARK, DMD, MSD, MS, PhD* TAE WEON KIM, DDS, MSD, PhD†

ABSTRACT The Clear Aligner can be used to correct tooth movement without involving extraction, surgery, and other adjunct orthopedic appliances. The Clear Aligner is a procedure that can be performed by either an orthodontist or a general dentist without computer simulation/ calculation. Since the Clear Aligner is fabricated from the stone model for new appliance at each or every other appointment, it is readily available to change the treatment sequence throughout the course of the treatment. The patient can receive any necessary dental proce- dures with ease during the course of the treatment. The treatment can also be easily resumed even if the patient has not worn the aligners for a period of time. The purpose of this article is to report dental anterior crossbite correction with a series of Clear Aligners. The Clear Aligner could be used as an alternative in appropriate cases for those who are reluctant with conventional appliances. CLINICAL SIGNIFICANCE The Clear Aligner, a clear removable orthodontic device, can perform tooth movement for the following: crowding resolution, space closure, arch expansion or constriction, anterior, or posterior crossbite correction, space maintenance or regaining, and other prosthodontic treatments combined with orthodontic treatment.1–3 This article illustrates an example of its use. (J Esthet Restor Dent 21:149–160, 2009)

INTRODUCTION patients seeking veneers, crowns, dental anterior crossbites is a and other laboratory-fabricated common orthodontic treatment nterior crossbites are not cosmetic restorations. Dental ante- that may be performed with a Aesthetically pleasing. Until rior crossbites are dental malocclu- removable or fixed appliance or a recently, the process of straighten- sions resulting from abnormal combination of both. This treat- ing the teeth typically has involved axial inclinations of maxillary ment has been recommended to appliances involving bands, brack- anterior teeth, whereas skeletal prevent abnormal enamel abra- ets, and wires that can be difficult anterior crossbites are usually part sions, fractures of anterior teeth, to clean. The desire for a cosmetic of a skeletal problem such as man- periodontal pathosis, and to solution to misaligned teeth has led dibular prognathism and midface produce a more esthetic dentofacial to an increase in the number of deficiency.4 The correction of complex and a better occlusion.5–7

*Director, Postgraduate Orthodontic Program, Arizona School of Dentistry & Oral Health, Mesa, AZ, USA †President of Korean Society of Lingual Orthodontics, Private Practice of Orthodontics, Seoul, South Korea

Furthermore, habitual mandibular 3 to 6 weeks is that the clinician lingually tilted lower right and left malpositioning and inappropriate can control tooth movement more canines. She had a Class I molar pattern of jaw musculature related precisely. The Clear Aligner is an relationship on both sides with to crossbite may adversely affect efficient orthodontic appliance pro- -1 mm overjet and 50% overbite. maxillary and mandibular growth duced periodically.12 It can be On smiling, the patient showed and potentiate temporomandibular easily fabricated by either an orth- excessive gingiva on the maxillary joint abnormalities.8 odontist or a general dentist in central incisors. Although the max- their own labs. In order to fabri- illary dental midline was coincident For esthetics, clear brackets may be cate a Clear Aligner, impressions with the facial midline, the man- placed, however, they can be irri- are taken for the working cast that dibular dental midline was deviated tating to the cheeks and gums are used with two or three differ- 1 mm to the right when the man- because they are large and bulky. ent plastic sheets (Duran, Scheu- dible was guided in centric relation, Lingual braces are a great option dental, Iserlohn, Germany) and a and the maxillary central incisors for those who want straight teeth pressure molding machine (Biostar, showed fractures on incisal edges in and a beautiful smile without Scheu-dental) or a vacuum machine centric relation (Figure 2). The pan- showing any braces.9,10 While the (Dentsply Raintree Essix, Metairie, oramic radiograph demonstrated lingual clinical techniques have LA, USA).1–3 Different plastic sheets no evidence of bone or dental been developed, lingual treatment are thermoformed on the setup pathology (Figure 3A). Cephalom- may not be cost effective due to model made for tooth movement etric analysis indicated a skeletal increased chair time. Invisalign using a vacuum former. The tooth Class III (ANB =-2) with hypodi-

(Align Technology, Santa Clara, movement is very efficient, and the vergent growth pattern (SN-GoGn: CA, USA) was developed for the patient feels comfortable. 27). The maxillary incisors were benefit of cleaning of the teeth retroclined (U1 to SN: 95) and the easily and going about normal life CASE REPORT mandibular incisors showed procli- without interruption.11–14 These A 28-year-old Korean female was nation (IMPA: 109) (Figure 3B). appliances are particularly popular referred to the orthodontist for The treatment objectives for this among adults who want to evaluation of anterior crossbite. patient were to correct the anterior straighten their teeth without the Her chief complaint was the unes- crossbite, to establish normal over- unflattering look of traditional thetic appearance of her upper bite and overjet, to align the ante- metal braces, which are commonly anterior teeth, which were behind rior teeth for ideal inclination, to worn by children and adolescents. the lower anterior teeth and she obtain a stable occlusal relation- wanted esthetic treatment with a ship, and to improve the patient’s The Clear Aligner can move the comfortable appliance. There were facial and dental esthetics by resolv- teeth easily without braces. It is no significant findings in her ing an anterior gummy smile. different from Invisalign, which medical and dental histories. The Before orthodontic treatment, she provides serial aligners from one patient presented a mesofacial, had a consultation with a periodon- impression.11–14 Rather than just symmetrical face, and a straight tist and a general dentist for gingi- delivering the aligners, the clinician profile (Figure 1). She showed mod- vectomy and restoration of upper should be the pilot of the treat- erate crowding on the upper arch central incisors. In order to correct ment. The main reason for the fab- with an anterior crossbite and mild anterior crossbite and to align the rication of the Clear Aligner every spacing on the lower arch with maxillary anterior teeth, oblique

Figure 1. Initial facial photographs. lateral and anterior-posterior (A-P) possible to determine ideal torque movements every 0.1 mm. This expansion was performed using and angulation of anterior denti- computer-compatible program three aligners (Figures 4–6). Two tion during setup model fabrication measures distance and angles of aligners were used to align the (Figure 8A).1–3 The Clear Aligner teeth movements on setup models lower arch (Figure 7). Because the also uses an aligner aid program (Figure 8B).1–3 patient had only mild spacing on (AAP) (IV-Tech) to fabricate a the lower arch in order to upright setup model. The AAP combined After jumping the bite, the patient the lower incisors, approximately with a 2D digital camera could be was referred to a periodontist for a 3 mm of interproximal reduction used to accurately measure the gingivectomy procedure to level the (IPR) was achieved in the lower movement. Before fabricating the gingival heights on the maxillary anterior dentition. setup model, the initial working central incisors (Figure 9). The cast photo is taken using a digital anterior crossbite was corrected When fabricating the setup model camera. After the target tooth is after orthodontic treatment. The for a Clear Aligner, the informa- moved to the desired position, it is patient was referred to the general tion of tooth angulations (e.g., fixed by the baseplate wax or Blue dentist for veneer restorations on upper incisor to SN and IMPA) Blokker (Scheu-dental) and a the maxillary central incisors. can be converted to the setup digital photo is retaken. Setup Acceptable overjet and overbite model using the Clear Aligner changes can be exactly measured were established after esthetic res- model checker (IV-Tech, Seoul, and verified by overlaying digital torations were finished (Figure 10). South Korea). Consequently, it is photos. It can control tooth The patient completed treatment

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Figure 2. Initial intraoral photographs.

with the same facial profile as pre- showed close to normal inclination gingivectomy and 1 month for treatment (Figure 11). The pan- considering her flat mandibular porcelain veneers on the maxillary oramic radiograph showed plane (Figure 12B). Clinical exami- central incisors. After the orthodon- excellent root parallelism nation of the mandibular position tic treatment and esthetic work was (Figure 12A). Cephalometric analy- did not show that the mandible done, the patient was given a new sis revealed a skeletal Class I shifted backwards, and there was Clear Aligner as a retainer. (ANB = 0) with hypodivergent no evidence of a centric relation- DISCUSSION growth pattern (SN-GoGn: 27). The centric occlusion shift. The total maxillary incisors (U1 to SN: 110) treatment time was approximately Anterior crossbite is defined as a showed decent inclination and the 6 months; 5 months for orthodon- malocclusion resulting from the mandibular incisors (IMPA: 100) tic treatment time including lingual position of the maxillary

A B

Figure 3. Initial radiographic views: A, Panoramic view. B, Lateral cephalometric view.

A B C

Figure 4. Diagrammatic representation of oblique lateral expansion (A) and A-P expansion (B). Two different plastic Clear Aligners fabricated from the setup model (C).

anterior teeth in relationship with one should attempt to guide the molars are in a Class I relationship the mandibular anterior teeth. The mandible in centric relation and and the incisors at an end-to-end correction of dental anterior cross- evaluate the molar and incisor rela- relationship, a dental correction can bite may involve lingual movement tionship. Furthermore, the relative be undertaken. The Clear Aligner of a mandibular tooth, labial size of the mandible should was chosen for her treatment movement of the maxillary tooth, be compared with the maxilla because her crossbite was a dental or both. Differential diagnosis of using model analysis along with origin and she wanted a clear dental versus skeletal anterior cephaolmetric assessment. removable appliance. The patient crossbite is essential in the selec- showed an improved overbite relation of cases that can be treated. In the absence of a family history of tionship after the appliance was Skeletal correction requires compli- Class III malocclusion, and upon removed (Figure 9). Once positive cated appliances, and the continu- manipulation of the mandible, if overbite is achieved, relapse is rare ous abnormal jaw growth can lead the incisors obtain an end-to-end in dental anterior crossbite; how- to relapse. To differentiate dental relationship, it may indicate the ever, adequate overbite depth to crossbite from skeletal crossbite, presence of a dental problem. If the “hold” the correction is necessary.

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Figure 5. Oblique lateral and A-P expansion was performed on upper arch using Clear Aligners.

A B C D

Figure 6. Intraoral photographs showing overjet and overbite changes before (A), during (B), after orthodontic treatment with gingivectomy (C), and veneer restorations (D) on maxillary central incisors.

A B C

Figure 7. Intraoral photographs showing alignment of lower arch before (A) and after (C) treatment using Clear Aligners (B).

Figure 8. A, The setup model is fabricated with torque on the upper arch using the Clear Aligner model checker. B, Aligner aid program (AAP) presenting the information of tooth movement. Pretreatment model is represented by the black lines and final setup model is represented by the red lines.

An important factor to consider in hygiene15,16 but also for esthetic during treatment because they are orthodontic treatment is whether reasons,11–14 removable Clear fabricated in the laboratory. In to use a removable or a fixed Aligner appliances have advan- addition, in orthodontic treatment appliance. Not only for oral tages. They reduce chair time combined with prosthodontic

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Figure 9. Intraoral photographs after orthodontic treatment with gingivectomy on maxillary central incisors.

treatment, after orthodontic treat- A potential disadvantage of this consistent with what might be ment is completed, the last aligner type of appliance is that it is highly expected with fixed appliances. could be used as a retainer until dependent on patient compliance.14 The other significant weakness is prosthodontic restorations are The aligner should be worn at least the aligner’s inability to move the completed. General dentists can 17 hours per day including sleep- root apex, such as in torquing or also perform restorative work with ing time,1–3 yet, current data translational movements. Tipping ease since the patient does not suggest that this rarely is an of teeth into the extraction space is have braces. Teeth can be moved issue.13,14 There were no compli- nearly impossible to avoid, even after temporary or final restora- ance issues with this patient and with fixed appliances, and tipping tions are finished as well. treatment time appeared to be is exaggerated in an adult patient.

A B

C D

Figure 10. Intraoral frontal and smiling views before (A,C) and after (B,D) orthodontic treatment including esthetic work, gingivectomy and porcelain veneers on maxillary central incisors.

Figure 11. Final facial photographs.

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those who are reluctant to use conventional fixed appliances.

DISCLOSURE The authors have no financial interest in any of the companies whose products are included in A B this article.

Figure 12. Radiographic views after orthodontic treatment: A, Panoramic view. B, Lateral cephalometric view. REFERENCES 1. Kim TW, Park JH. An aesthetic orthodontic treatment option: fabrication and applications. Dent Today 2008;27:132–5.

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