Multidisciplinary treatment with the lingual orthodontic technique - a case report.  

Stefan Beckman DDS, Med. Dent, Holland, Rony Lev-Dor D.M.D., Silvia Geron D.M.D., M.Sc, Israel

Abstract
This case report shows the treatment of a 27 year old female with early adult periodontitis, a Class I malocclusion, missing upper left permanent canine and all first premolars, and an upper midline dental shift to the left. Treatment was carried out using a multidisciplinary approach. The malocclusion was resolved using a lingual orthodontic technique, while the periodontal condition was constantly monitored by a periodontist, and the prosthetic treatment involved the insertion of an implant for the missing maxillary left canine. The specific biomechanical considerations of the lingual technique used, the periodontal maintenance, and complications of periodontal disease during orthodontic correction for this patient are discussed.

Introduction
The orthodontic treatment of a patient with periodontal disease poses a challenge to the orthodontist (1,2). Previous studies have shown that the periodontal condition of patients with periodontitis may rapidly worsen during orthodontic tooth movement, if the periodontal disease is left unresolved (1). Constant monitoring of the periodontal condition is necessary in order to prevent attachment loss during treatment
The periodontal treatment includes periodical screening, and adherence to strict oral hygiene protocols, periodic initial preparation, and regular debridement. In addition, periodic measurement of pocket depth is necessary to monitor the periodontal condition. If the periodontal condition deteriorates despite the above mentioned
measures, orthodontic tooth movement must be suspended until it is brought under control (1). Periodontal surgery may be necessary after orthodontic treatment.

Orthodontic tooth movement must then be kept to a minimum, and certain orthodontic tooth movements, such as root torque must be avoided. It may be necessary to accept a compromise in the final result of the orthodontic treatment. Root resorption in combination with periodontal disease may significantly worsen the prognosis of the affected teeth.  Lingual orthodontic treatment has significant advantages over the labial technique, when it comes to esthetic considerations. The visibility of labial brackets may deter adult patients from seeking orthodontic treatment, especially if the patient is active in public life. Due to their "invisibility", fixed lingual appliances offer an acceptable alternative for these patients. The effect on speech by the lingual technique may occur with placement of the appliance. However, this can be addressed by specific exercises performedby the patient.

After a period of adaptation patients function normally with the appliance. Of more lasting significance is the effect of such an appliance on the oral hygiene and health of a given patient. The position of the appliance does not permit direct observation by the patient to facilitate proper oral hygiene. In addition, the variability of lingual surface dental morphology requires that larger amounts of bonding material be used to dictate individualized bracket positioning for use in the straight wire technique.
The increased amount of bonding material leads to plaque retention and exacerbates gingival inflammation. Therefore, a strict oral hygiene protocol is necessary in order to avoid periodontal inflammation.

Diagnosis and etiology
A 27 year old female patient arrived at the university clinic for orthodontic consultation. She was referred by her general dentist with the chief complaint of "crooked teeth".  She presented a well-balanced, symmetric face with competent lips (Figure 1). Intraorally she presented with a half-cusp mesiocclusion (Cl III) maloccusion at the molars, 1mm overjet, and 22% over bite. There was an open bite in the area of teeth 25 and 26, and the maxillary right canine was in cross bite tendency. The maxillary midline was shifted 5mm to the left. The maxillary arch was missing both first premolars(14, 24) and third molars (18, 28), as well as the left canine (23) and the left second molar (27). If space will be required to replace the missing 23 there exists 2.5 mm lack of space in this arch. Under the current situation there is excess space of 5.5 mm. The arch form was ovoid, a slightly greater compensating curve on the right side.

Of note was the mesial crown angulation of the second premolars and first molars There were several rotated teeth (16,15,12,11,21,22,25,26), and a 7mm space between the 13 and the 15. (Figure 2) The mandibular arch presented with crowding of 4 mm, an ovoid arch form, a mild Curve of Spee, several rotated teeth (33,41,43,45), and mesial crown angulation of all molars, premolars, canines. Radiographic and clinical examination (Figure 3) revealed active carious lesions, root resorption on the upper centrals, and some horizontal bone loss. The patient's oral hygiene was fair-to-poor with local periodontitis and pockets deeper than 4 mm in the molar region. In addition, there were decalcifications of the maxillary dentition and some enamel pitting incisal / buccal 11,21. Cephalometrically, the patient had Class I skeletal relations.

Treatment Objectives
The objectives of orthodontic treatment were to avoid deterioration of the periodontal condition while creating space for future prosthetic  eplacement of 23, to correct the upper midline, to align the arches, and to resolve crowding while maintaining inclination of lower anteriorteeth.

Treatment Alternatives
Alternative treatment plans included the extraction of one mandibular incisor, or both first molars. However, these were rejected because the resulting Bolton imbalance, and the over-riding periodontal situation, respectively.

Treatment progress
Pre-orthodontic
Following the gathering of orthodontic diagnostic records, the patient was referred to the dental clinic of the University for dental treatment, and initial periodontal preparation. Tooth number 27 could not be saved and had to be extracted. The 38 and 48 were also extracted. The existing periodontitis was brought under control by initial preparation alone without the need for surgical intervention.

Orthodontic treatment
To meet the above mentioned objectives, it was planned to open a space between 22 and 25 while shifting the dental midline to the right. This was done using a combination of compressed on-arch open coils to create the space for prosthetic replacement of tooth number 23, and elastic chain to "pull" the incisors to the right. In the mandibular arch, crowding would be resolved by extraction of teeth numbers 38 and 48, and by uprightening of the molars. This is to be achieved through bracket positioning where the molar brackets would be positioned with some degree of mesio-gingival angulation. In addition, space would be gained for the rotated canines with the use of coil springs. Due to the patient's esthetic demands, lingual fixed orthodontic appliances were utilized in both arches. Lingual brackets were placed on the maxillary incisors and right canine (Ormco 0.018 inch slot), on premolars, both first molars and right second molar, (Ormco 0.022 inch slot), and alignment was carried put using preformed 0.017x.017 inch Copper nitanol arch wire (Figure 4).

One month after upper bonding, the lower lateral incisors and the left central incisor, the 2nd premolars, the 1st and 2nd molars were also bonded. The molar brackets received a slight degree of mesial tip, in order to facilitate their uprightening (Figure 5). The same archwires were used for initial leveling and alignment. A coil spring was inserted to create space for alignment of 41 which was bonded when its alignment  became possible (Figure 6).

Two months after bonding of the maxillary dentition, an open NiTi coilspring was inserted in a compressed state between teeth 22 and 25. At the next visit, the wire was changed to SS .016, and a chain  was added between 13 and 15. The simultaneous action of the coil spring and the chain moved the entire upper anterior segment to right and corrected the midline (Figure 7). Unfortunately, periodontal inflammation arose during the shifting of the anterior segment. This caused some delay in the treatment. After thorough debridement, orthodontic treatment could continue.

Concomitantly, coil springs were inserted between the mandibular lateral incisors and the second premolars. They opened space for the alignment of the canines (Figure 8). After 4 months, enough space was created and the lower canines were bonded along with clear buttons on their labial surfaces between which an elastic chain was attached to facilitate their alignment. This was further enhanced by the placement of a section of elastic chain to the lingual brackets of the mandibular canines to the first premolars (Figure 9). It was necessary to create an  undercut from composite to prevent the chain from slipping over the incisal edge.

After 7 months, the upper midline was corrected and enough space was created for the implant at the site of the missing 23. At this stage, the patient demanded a temporary solution for the gap created at the site of the missing 23. An acrylic tooth was bonded to the distal surface of 22, which was ground out of occlusion and

articulation (Figure 10). Apart from esthetic benefits, the tooth also served as a space maintainer. The acrylic tooth remained in place until debonding of the upper arch.

Final adjustments consisted of derotation of the 22, and vertical height correction 11 and 22. Correction required mesiodistal width reduction of the 31 and the 41. However, the periodontal condition remained of concern, and some root resorption became apparent during this period. A gingival dehiscence developed at the labial surface of the 31. Although lingual root torque could have improved the gingival condition, the ongoing tendency for root resorption and the overall periodontal condition contraindicated extensive root movements. Therefore, it was decided to treat the dehiscence after debonding with gingival grafting. The final phase lasted 4 months, and 5 months after debonding of the upper arch, the brackets of the lower arch were removed . The periodontist encountered difficulties in debridement which was difficult to accomplish while the lingual brackets were present, therefore, it was recommended that the orthodontic appliance be removed. Final adjustments were to be accomplished with a removable appliance. This approach would allow the periodontist better access to the lingual surfaces of the teeth for initial preparation (Figure 11). Three months after debonding of the upper arch, an implant was inserted at the site of the 23 (Figure 12). The implant is planned for restoration with a crown after osseointegration.

Retention
For the maxillary dentition a Hawley retainer was planned for both retention as well as minor tooth movement. However, at delivery of the  ppliance the patient rejected it because she experienced speech difficulties. Therefore, the Hawley was not used and an Omnivac retainer was manufactured instead and final adjustments were postponed until after insertion of the implant.

Treatment results
Significant improvements in the patient's smile were noted (Figure 13,14).There was a remarkable improvement in the occlusion. The upper midline was almost entirely corrected and a solid Class I wellintercuspated occlusion with proper overjet and overbite was achieved (Figure 15).

A comparison of the pretreatment and the posttreatment cephalograms showed that no changes occurred in the inclination of the maxillary and mandibular incisors during treatment and that the patient's skeletal pattern was not altered by mechanics (Figure 16). The posttreatment panoramic view showed the roots of the teeth in both arches to be well angulated and aligned, except for the mesial angulation of the 32. (Figure 17). Unfortunately, apical root resorption was detected on radiographic examination at the 11, 21 and 22. Overall, no additional bone loss during treatment was noted, except for the distal surface of the 36, where a three-walled bony defect developed. However, a preexisting marginal height discrepancy between the 36 and the 37 existed pre-treatment. The bone level between both teeth did not follow the marginal crests. Consequently, the uprightening of the 36 may have caused a triangular defect in this area (Figure 17).

References
1. Kokich VG. Managing treatment for the orthodontic patient with periodontal problems. Sem thod 1997;3:21-38
2. Kokich VG. Esthetics: the orthodonticperiodontic- restorative connection. Sem Orthod 1996;2:21-30

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Adult and Lingual Orthodontics
EDITORS:
Dr. Silvia Geron D.M.D., M.Sc
Dr. Rafi Romano D.M.D., M.Sc
Dr. Pablo Echarri D.M.D., M.Sc