A young adult came to our attention with a request for aesthetic orthodontic treatment to improve the excessive “flaring” of his maxillary incisors. Intraoral analysis showed a inter-arch Class II subdivision relationship with a Class II head to head molar and canine relationship on the right and a solid Class I relationship on the left. The lower dental midline was deviated to the right with respect to the upper dental midline. There was a dental cross-bite between elements 1.4 and 4.4, moderate crowding and an increased overjet value in both arches. In the upper arch, diastemas were present at elements 1.6, 1.5 and 1.4.
The objectives set were to resolve the inter-arch Class II subdivision relationship using a mixed distalisation mechanism of the dental elements in the first quadrant and mesialization of the elements in the fourth quadrant, and to centre both dental midlines with the face, resolve the crowding in both arches and to obtain excellent coordination among them. The proposed orthodontic treatment was based on the use of F22 aligners combined with the unilateral use of Class II elastics after the patient’s request to be treated with an aesthetically pleasing appliance that would not affect his social and professional domains negatively.
After the intraoral scan of his arches, an operational set-up comprising 20 steps for both jaws was programmed with the simulation of the correction of the Class II relationship on the right side using Class II elastics. The planned distalisation involved a simultaneous movement (so-called en-masse) of the entire first quadrant. Grip points were programmed at the level of elements 1.6, 1.7, 4.5, 4.4 and 4.3 together with an IPR of 0.2 mm for each contact point from the mesial surface of element 4.6 to the distal surface of element 4.2. After approximately ten months of treatment, the initial F22® aligner phase was completed. Nevertheless, a further three steps per arch had to be finished in order to improve the occlusal engagement and the de-rotation of elements 4.6, 1.6 and 1.5.
All intraoral objectives were achieved: namely, Class I canine and right molar, both dental midlines were centred, good overjet and overbite relationship, good coordination between the arches and resolution of crowding.
