TREATMENT ALTERNATIVES
To correct the skeletal malocclusion, different treatment options were considered. A mandibular setback alone would not have been ideal for facial esthetics and would not have fulfilled the patient’s expectations. As a result, to obtain an adequate facial balance, a mandibular setback was combined with maxillary advancement. Furthermore, posterior crossbite due to maxillary deficiency inevitably required double-jaw surgery. A surgery-first approach was discarded by the authors because the extrusion of the upper right second molar would have caused great instability of the occlusion.
Both vestibular and lingual appliances were considered for the orthodontic preparation. Lingual brackets (Win Lingual System) were preferred to the vestibular ones for the complete customization and the high torque control of the incisors owing to the ribbon archwire configuration. In the mandibular dental arch, the space closure treatment option was considered as was the torque increase of the mandibular incisors. Torque control provided by the customized lingual appliance and the ribbon archwire was considered to be the best alternative to obtain both of these results. Another advantage of a customized lingual appliance is the opportunity to create temporary dental elements already at the set-up phase, 3D print them, and apply them to the archwire during therapy. This procedure was very helpful for 2 reasons: First, it provided an esthetic solution for the patient and did not leave an open wide space during the treatment; and second, it permitted easy management of space closure of adjacent teeth.
In the maxillary dental arch, 2 options were considered: space closing or space opening for maxillary lateral incisors and canines. Space closure can be a valid alternative when it is necessary to close the space of 1 tooth; in this case, however, the amount of space to close exceeded 10 mm per side and it would have made the management of the anchorage and treatment duration particularly challenging.
For the final prosthetic rehabilitation, the number of implants per side was discussed. The oral surgeon and the prosthodontist preferred to have only 1 implant per side in the canine position and a cantilevered reha- bilitation of both elements. This solution provides a better periodontal outcome, in particular when considering the interdental papilla that is hard to manage between 2 adjacent implants.
TREATMENT PROGRESS
Indirect bonding procedure was performed following the clinical protocol of Win Lingual System (Fig 4, A).
Extraction of the maxillary deciduous lateral incisors and canines was performed later during therapy to avoid any dental movement that could have affected the precision of the indirect bonding tray. The archwire sequences were: 0.14 NiTi, 0.16 x 0.22 NiTi, 0.18 x 0.25 NiTi, 0.16 x 0.24 SS with 13° of extra torque, and 0.18 x 0.25 TMA in the maxillary dental arch and 0.14 NiTi, 0.16 x 0.22 NiTi, 0.18 x 0.25 NiTi, 0.18 x 0.25 SS reduced in the posterior straight segments and 0.18-x 0.25 TMA in the mandibular dental arch.
In the maxillary dental arch a miniscrew was placed in the right tuber maxillae from the first phase of therapy to help the second molar intrusion movement. The diastema closure between upper central incisors was started from the beginning with the use of a light elastic chain.
Deciduous lateral incisors and canines were extracted when the 0.16 x 0.22 NiTi archwire was applied, because the temporary crowns planned in the set-up need a rectangular archwire for their stabilization (Fig 4, B).
In the mandibular dental arch space, closure was started with the use of light elastic chains on round and rectangular NiTi archwires and proceeded with the use of double-cable powerchain mechanics on rectangular SS archwires. Metal and composite buttons were applied to help the maxillofacial surgeon during the surgical phase.
The surgeon planned maxillary advancement with the use of a modified Le Fort II osteotomy, a mandibular setback with a bilateral sagittal split osteotomy, and a genioplasty (Fig 4, C). Titanium plates were used for the final fixation. Genioplasty was planned to change the anatomy of the symphysis and improve the final esthetic result.
After healing time, cone-beam computed tomography (CBCT) was performed with a radiolucent splint to plan the computer-guided implant surgery. Implants were placed in the canine site with the use of flapless guided surgery (Fig 5, A-D). After 3 months, cantilevered temporary bridges were delivered. Cantilever bridges were preferred to obtain a better outcome of the inter- dental papilla between the canine and the lateral incisor. After the gingival condition phase, final prosthetic rehabilitation consisted in 2 veneers for the central incisors and 2 zirconia-ceramic cantilevered bridges for the canine and lateral incisor (Fig 5, E).
TREATMENT RESULTS
After 36 months of active treatment, the patient showed an Angle Class I molar and canine relationship, skeletal asymmetry and midline corrections, and a full correction of the overbite and overjet. Maxillary and mandibular dental arches presented ideal alignment and leveling. All spaces in the mandibular dental arch were closed, and in the maxillary dental arch all closed spaces and frontal teeth in the maxillary arch presented an ideal proportion thanks to the correct management during treatment and prosthetic rehabilitation. Posterior crossbite was completely resolved, thanks to surgical maxillary advancement and good arch coordination during orthodontic treatment (Figs 6 and 7).
The whole facial esthetics was significantly improved. The mandibular protrusion and maxillary deficiency were completely solved by means of orthognathic surgery. The patient had a good and natural display of his teeth at rest and while smiling, lips were competent, and he was totally satisfied with the treatment result. Stable occlusion was achieved with no premature contacts and appropriate incisor and canine guidance.
The final panoramic radiograph confirmed an adequate root inclination and parallelism in the anterior and the posterior regions, an adequate distance between implants and the adjacent teeth, healthy tissue around dental implants, and no sign of marginal bone loss (Fig 8).
The lateral radiograph and cephalometric analysis showed a good balance of the skeletal pattern, a good profile of the soft tissue, and proper inclinations of the maxillary and mandibular incisors in relation to the maxilla and mandible (Fig 8; Table I).
The tracing superimposition showed the maxillary advancement with posterior impaction, the mandibular setback, the maxillary incisors retroinclination, and the optimal torque control of the mandibular incisors (Fig 9).
Upper and lower Essix splints were given to the patient for use nightly. After 1 year, the Essix splint use was reduced to 3-4 nights a week.
After 2 years of follow-up, the gingival levels were satisfactory (Fig 10). Particular attention was given to the interdental papilla between maxillary canine and lateral incisor, which looked natural and filled the site. The choice of a single implant supporting a cantilevered bridge, instead of a 2-implant rehabilitation, associated with an accurate management of the temporary bridge, were essential to attaining this result. The patient maintained ideal oral hygiene, with no sign of marginal inflammation and absolute stability of the periodontal and perimplant soft and hard tissue. The patient did not show any temporomandibular problems during treatment, retention, and postretention periods. Maximum opening was in the normal range, and no mandibular shift during opening movements was evident.
