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Dental Tribune United Kingdom Edition

July 201416 CAD/CAM Tribune United Kingdom Edition Non-extraction treatment of a Class II case with Author: Khaled Abouseada A dult orthodontic pa- tients insist on aesthetic treatment options that have the least possible impact on their work and life. Clear aligners are an excellent treat- ment option that is well suited to many comprehensive or- thodontic treatment plans. You may have already fig- ured out that case selection is essential, and some movements are more difficult to perform well with removable aligners. Incognito lingual braces (3M ESPE) are an ideal treatment option for adult patients who are best treated with a fixed system and who are looking for invisible orthodontics. They are also perfect for patients who are not committed to dealing with removable aligners. Lin- gual braces are an exciting ad- vancement in orthodontic care, and many patients are thrilled. I would like to present a brief background on the Incognito lingual braces system, followed by a discussion of a case I treat- ed with lingual braces and why I chose this system.1 The Incognito appliance is manufactured using state-of- the-art CAD/CAM technology. The first step in the fabrication process is taking accurate poly- vinyl siloxane impressions and bite registration using polyvinyl siloxane, and then creating a model in plaster and a diagnos- tic wax-up thereafter (accord- ing to my direct instructions). The final model is then sent to me digitally for feedback, and I can make a series of changes until I am satisfied with the final result. The final model is then scanned with a 3D scanner and the brackets are designed on the computer. The bracket and archwire system consists entirely of in- dividualised components. The bracket bases and bodies, the position of the bracket body on the bases, the bracket-slot ori- entation (ribbonwise), the di- rection of the archwire insertion (vertical or horizontal) and the archwire geometry are all indi- vidually adjusted to each tooth, according to malocclusion and the orthodontist’s instructions. Rapid prototyping technology is used for the manufacturing of the lingual brackets. The braces are then cast from gold alloy, mounted in a flexible indirect bonding tray, and shipped out ready to be bonded. Direct bonding is fea- sible too, owing to the extended individual bases. Bending archwires is one of the most difficult tasks in orthodontics. In this system, computer-operated bending of archwires using robots is used to manufacture precisely shaped archwires. Even super- elastic archwires can be pre- cisely shaped. This helps solve three major problems in lingual orthodontics: 1. Patient discomfort during the adaptation phase: The appli- ance is designed to be as flat as possible, not much higher than a bonded retainer; this signifi- cantly improves patient comfort. 2. Difficulties in re-bonding: The customised bracket base covers the major part of the lin- gual tooth surface and therefore allows direct re-bonding with- out the need for any other posi- tioning aids. 3. Inaccuracies in finishing: Inaccuracies of the slots due to production and resulting vari- ation in torque play are now part of the past, owing to In- cognito. Measuring rates show divergences of not more than 0.008mm between the slots. The precisely shaped archwires also make high-standard finish- ing easily achievable.2, 3 Figure 1 shows the different steps in manufacturing braces with the Incognito system. This case report describes the treatment of a patient with a skeletal Class II malocclusion due to a retrognathic mandi- ble and protrusive maxilla. He also had a congenitally missing mandibular left central incisor. The extraction of a single man- dibularincisor can be employed as a compromise treatment of certain malocclusions if the end result fulfils the requirements for a healthier dentition that is functionally and aesthetically harmonised in relation to the surrounding structures.4 In this case, one of these incisors was missing so extraction was not necessary. The Class II malocclusion was corrected by non-extrac- tion orthodontic treatment with a CAD/CAM fixed lingual ap- pliance (Incognito). The Class III molar relationship had not changed at the end of treatment, but a Class I canine relationship was achieved and the facial pro- file improved owing to improve- ment in the position of the man- dibular incisor in relation to the mandibular plane, which affects the position of the lower lip. Diagnosis and aetiology The patient was male, aged 23 years and nine months, and had the chief complaint of crowding of the maxillary and mandibular anterior teeth. He had Class III canine and molar relationships on both sides, a 2mm overjet, a 4mm overbite, a missing man- dibular left central incisor, the maxillary midline was coinci- dent with the midsagittal plane, the mandibular midline was shifted to the left, the maxil- lary dental arch had about 7mm of crowding and lower dental arch had 8mm of crowding, ex- cluding the width of the miss- ing mandibular incisor, and the maxillary lateral incisors were in crossbite (Fig 2). According to cephalomet- ric analysis, there was a Class II jaw relationship and normal vertical facial height. The pa- tient was in good health and his medical history showed no contra-indications to orthodon- tic therapy (Fig 3). Treatment objectives The treatment objectives in- cluded correction of the maxil- lary and mandibular crowding, improvement of the dento-al- veolar and maxilla-mandibular relationships, improvement of facial aesthetics, and establish- ment of a stable occlusion and better smile. Treatment alternatives Three treatment options were suggested to the patient. The first alternative entailed labial orthodontics using either metal or clear brackets. The second option entailed lingual ortho- dontics, as the aesthetic demand was very high for the patient and clear aligners would not have been able to achieve the needed results. Both Options one and two were non-extraction. The third option was to ex- tract all four first premolars but this would have affected the facial profile negatively. Af- ter detailed discussion with the patient, we chose Option two, non-extraction using a lingual appliance. Treatment progress Treatment began with cus- tomised, pre-adjusted, CAD/ CAM fixed lingual appliances (0.5588mm slots) placed on both the maxillary and man- Fig. 1 Different steps of manufacturing of Incognito System Fig. 3 Final photographs show normal overbite and overjet Fig. 2 Extraoral and intraoral photographs before treatment showing severe upper and lower crowding and retruded lower lip. CAD/CAM lingual orthodontic system a missing mandibular central incisor using a

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