Interdisciplinary Approach for Esthetic Management of an Adult Patient with Reverse Articulation

Avinash S. Bidra, BDS, MS, FACP; Flavio Uribe, DDS, MS; and Alexander Askalsky, CDT, MDT, MDP

Reverse articulation or cross-bite is defined as “an occlusal relationship in which the mandibular teeth are located facial to the opposing maxillary teeth.”¹ This condition can occur either in the anterior or posterior region. In the anterior region, it is generally caused by a maxillo-mandibular skeletal discrepancy where the mandible is usually larger and prognathic and the maxilla is smaller in size and retrognathic. This mismatch between the size and position of the jaws causes a reverse articulation of the anterior teeth.² However, when the cross-bite is localized to one tooth, the etiology is more commonly related to the lingual ectopic eruption of a maxillary anterior tooth or the labial ectopic eruption of a mandibular anterior tooth. Additionally, the cross-bite could be related to moderate crowding in both arches, causing labial displacement of a mandibular tooth and lingual displacement of the corresponding maxillary antagonist.²

Statement of Problem

Reverse articulation of single or multiple teeth in the anterior region can compromise esthetics and occlusion.³ Treatment planning for optimal correction of this situation in adult patients is complex and multidisciplinary, and the duration of treatment is generally lengthy.

Treatment Options for Reverse Articulation

Orthodontic therapy is the most conservative and effective solution for reverse articulation that can provide optimal esthetics and occlusion.² However, orthodontics is associated with an extensive duration of treatment that may be unacceptable to many adult patients. Non-orthodontic treatment options for correction of reverse articulation are generally considered compromising and include restorations on aggressive tooth preparations, abnormally bulky restorations, or extractions followed by prosthetic replacement. Other less common options include selective recontouring of teeth, surgically repositioning teeth, and segmental osteotomy of the affected teeth.⁴

The purpose of this clinical report is to describe the interdisciplinary management of an adult patient with reverse articulation. Treatment included a combination of orthodontic, prosthodontic, and periodontal therapy.

Case Report

A 56-year-old woman presented to the prosthodontist for esthetic evaluation of her maxillary anterior teeth (Figure 1 and Figure 2). The patient was referred by her periodontist, who had diagnosed her with chronic adult periodontitis many years ago and was providing periodontal maintenance therapy. Her medical history was noncontributory, with no contraindications for dental treatment. The patient had recently undergone a rhytidectomy (face lift) procedure by her plastic surgeon and desired a consummate esthetic enhancement. Clinical examination revealed that the patient presented with an Angle’s Class II malocclusion with a deep vertical overlap of 5 mm in the anterior region (Figure 3). The maxillary central incisors were retroclined, the maxillary right lateral incisor had a large composite resin restoration in the cervical region, and the left lateral incisor had an esthetically compromised metal–ceramic crown. Both lateral incisors had long clinical crowns revealing a loss of clinical attachment level. A complete reverse articulation was noted in the left canine region (Figure 4). The maxillary left canine showed infraeruption with a dull sound on percussion, clinically ruling out the possibility of ankylosis. The patient had a congenitally missing right maxillary canine, which further compromised esthetics and occlusion. The maxillary and mandibular midlines were not coincident, but the maxillary midline appeared acceptable with the midline of the face and mouth.⁵ Radiographic examination revealed generalized horizontal bone loss, with no clinical mobility (Figure 5). The patient had multiple restored teeth, and her oral hygiene was excellent.

Clinical photographs were taken and diagnostic casts were prepared and mounted on a semi-adjustable articulator. The patient requested an esthetic treatment plan that not only could be accomplished speedily, but also provided a long-term solution. Additionally, she desired improvement in the shade of all her anterior teeth. A multidisciplinary team consisting of a prosthodontist, orthodontist, oral surgeon, and periodontist educated and counseled the patient about undergoing orthodontic treatment for correction of the reverse articulation. The patient, however, refused this option, as she was unwilling to undergo a treatment that did not offer fast results. The patient was informed about alternative treatment options consisting of: 1) extraction of maxillary and mandibular canines, followed by replacement with implant-supported restorations or fixed partial dentures; or 2) elective endodontic treatment on maxillary and mandibular canines, followed by cast dowel and core and crown restorations on both teeth. She was educated regarding the challenges in obtaining optimal dental and gingival esthetics and proper occlusion using these options; a diagnostic wax-up was performed in order to instruct the patient about these challenges (Figure 6). After a few weeks and much deliberation, the patient finally consented to undergo orthodontic treatment.

The definitive treatment plan involved orthodontic therapy to correct the reverse articulation followed by bleaching of her maxillary and mandibular dentition and replacement of the existing crown on the maxillary left lateral incisor. It was also decided to fabricate an all-ceramic crown on the right first premolar to make it appear like a canine and enhance the esthetic result.

Orthodontic treatment began after consultation with the periodontist in order to ensure sound periodontal health during the course of treatment. The treatment plan consisted of achieving space to rotate and labially displace the maxillary left canine. Interproximal reduction distal to the maxillary left canine was planned to avoid labial tipping of the incisors and displacement of the maxillary midline to the right. Finally, only the maxillary arch was to be treated. Although fixed appliances were recommended to predictably correct the cross-bite, the patient requested clear removable aligners to correct her orthodontic problem. Treatment progressed with Invisalign^® (Align Technology, Inc., www.aligntech.com) until the canines were in an end-to-end relationship. At this time it was decided to continue with fixed appliances in order to gain better control of the required orthodontic movements. The maxillary left canine was brought into the arch with fixed appliances (Figure 7). The maxillary left premolars and molars were slenderized with a disc by approximately 1 mm per interproximal contact, and the spaces were closed. The buccal occlusion was maintained on both sides and the left canine was placed in an adequate transverse relationship. The total treatment time for orthodontic alignment was 24 months (Figure 8).

After removal of the orthodontic brackets, the patient was referred back to the prosthodontist for continuation of esthetic treatment. New diagnostic casts were prepared and mounted on a semi-adjustable articulator. Because the patient requested that her teeth shade be improved, bleaching trays were prepared and a home-based bleaching protocol was prescribed using 14% hydrogen peroxide gel (Perfecta^® Rev^®, Premier Dental, www.premusa.com). At a 3-week follow-up, the patient requested further improvement in teeth shade and shape with porcelain veneer restorations. The treatment plan was modified at this stage to include porcelain veneers on the maxillary central incisors and the maxillary left canine. All-ceramic crowns were planned for the maxillary right premolar and both lateral incisors. A new diagnostic wax-up was accomplished accordingly and presented to the patient (Figure 9).

Tooth preparations were then completed according to the diagnostic waxing. The existing crown on the maxillary left lateral incisor was removed and the existing tooth preparation was refined. To facilitate appropriate bonding procedures, special care was taken to ensure that the tooth preparations for porcelain veneers were restricted to enamel (Figure 10). A final impression was then made using polyether impression material (Impregum™ Penta™ Soft, 3M ESPE, www.3MESPE.com), and dies were fabricated. The restorations were waxed-up according to the diagnostic work-up, and lithium disilicate restorations (IPS Empress^® Esthetic, Ivoclar Vivadent, www.ivoclarvivadent.com) were then fabricated. The restorations were tried in the mouth and then luted using resin cement (Variolink^® II, Ivoclar Vivadent) (Figure 11). A mutually protected occlusal scheme with canine guidance was accomplished (Figure 12). The patient was given postoperative instructions and educated about oral hygiene measures. She was provided with maxillary and mandibular removable vacuum-formed orthodontic retainers to be worn at night. She was then referred to her periodontist for maintenance of periodontal health and was placed on annual recalls (Figure 13 and Figure 14). At a 2-year follow-up, the patient remained satisfied with the esthetics of her teeth as well as her treatment decision. The positions of the teeth, the restorations, and the patient’s periodontal health remained stable.

Discussion

A plethora of information is available to the public regarding “cosmetic dentistry.” Patients, however, often are misinformed or misconstrue the information regarding treatment outcomes that have been demonstrated to be cosmetic. Propaganda surrounding the term “cosmetic dentistry” and the attributes associated with it is plentiful.

Presently, the American Dental Association,⁶ the Academy of Prosthodontics’ Glossary of Prosthodontic Terms^,1 the American Academy of Periodontology’s Glossary of Periodontal Terms,⁷ and the American Association of Orthodontists’ Glossary⁸ do not have a definition for cosmetic dentistry. The Glossary of Prosthodontic Terms defines esthetics as “pertaining to the study of beauty and the sense of beautiful”; it defines dental esthetics as “the application of the principles of esthetics to the natural or artificial teeth and restorations.”¹ With increased access to information, patients often have higher demands and expectations of esthetic outcomes of their dental treatment. There is also a predilection for patients to seek treatment modalities that offer immediate results.^3,9 Though such treatment modalities may be effective in certain situations, patients need to understand that many dental problems require treatment methods that involve reestablishing appropriate interocclusal relationships necessary to achieve long-term successful outcomes.³ Adult orthodontic therapy is one such treatment that, while it does not offer instant results, can be rewarding in the long term.^10,11 Common alternatives to adult orthodontic therapy are extractions, unconventional or aggressive tooth preparations for fixed restorations, or implant therapy. All of these may compromise the esthetic and functional outcome. Furthermore, upon an analysis of scientific literature, it has been argued that aligning a healthy tooth using porcelain veneer restorations is not a conservative procedure, and more moderate treatment options, including orthodontics, should first be offered to the patient.⁹

Patient education and guidance play major roles prior to initiation of orthodontic therapy in adults. Many adults are not psychologically prepared to wear an orthodontic appliance or are unwilling to commit to the treatment due to the lengthy duration.¹² The patient in this case had been misinformed about dental esthetics and was driven by a desire to obtain “instant cosmetic” results. Patient education involved explanation of advantages and disadvantages of all treatment options and included demonstration through a diagnostic wax-up. The final treatment plan chosen was based on a confluence of factors. Though she was periodontally compromised, orthodontic therapy was the primary treatment of choice because the authors considered the alternative option of extraction and implant therapy to be aggressive. Orthodontic treatment in periodontally compromised patients has been successfully documented in the literature.^13,14 However, it requires careful monitoring of oral hygiene and gingival health during the course of the treatment. Therefore, close communication with the periodontist is important to ensure that the patient’s periodontal condition does not deteriorate during orthodontic treatment.¹³ The oral hygiene of this patient was good and she underwent periodontal maintenance therapy during the entire course of orthodontic treatment.

Because the patient had high esthetic expectations, important parameters such as midline, symmetry, tooth proportions, and smile arc were carefully scrutinized in the esthetic treatment plan.^15,16 Correction of reverse articulation involved shifting the position of the dental midline by 2 mm to the right in order to accommodate the occlusal movement of the left canine. However, the literature is clear that the tolerance to a deviated dental midline is 2 mm to 3 mm.^17-20 This had been explained to the patient prior to initiation of orthodontic therapy. Because the patient was congenitally missing her maxillary right canine, the right first premolar was prosthetically converted to a canine in order to establish symmetry and balance in her smile.¹⁵ Furthermore, this tooth had a large preparation for an amalgam restoration. The shape, proportions, and display of the patient’s maxillary central incisors with lips at rest and smile were satisfactory. The porcelain veneer restorations were fabricated primarily to improve their shade, because the patient was unsatisfied with bleaching. Admittedly, orthodontic extrusion of the lateral incisors would have helped to attain esthetic gingival levels; however, since the patient had horizontal bone loss around these two teeth, the authors decided that it might be an unfavorable option. Furthermore, because the patient did not reveal her gingival margins in maximum smile, the need for such orthodontic extrusion could not be clearly established. The lengths of the lateral incisors were shortened as much as possible to improve esthetic tooth proportions and to create a dominant central incisor effect and a smile arc consonant with the lower lip.^14,15,21 This helped to obtain a youthful smile, which satisfied the patient.

Conclusion

This clinical report describes the interdisciplinary management of a complex esthetic situation in a periodontally compromised patient who had high esthetic expectations and desired a speedy solution. The treatment involved patient education and orthodontic correction of reverse articulation in the canine region. This was followed by bleaching therapy and fabrication of all-ceramic restorations on the six maxillary anterior teeth. Close communication among different specialists is needed for treatment of complex esthetic cases.

References

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About the Authors

Avinash S. Bidra, BDS, MS, FACP
Assistant Professor and Assistant Program Director
Post-Graduate Prosthodontics
University of Connecticut School of Dental Medicine
Farmington, Connecticut

Flavio Uribe, DDS, MS
Associate Professor and Program Director
Division of Orthodontics
University of Connecticut School of Dental Medicine
Farmington, Connecticut

Alexander Askalsky, CDT, MDT, MDP
Master Laboratory Technician
Metropolitan Dental Laboratory
Monroe, Connecticut