SOX is an abbreviation for the ‘social six’ front teeth, and SOX retainers are designed to maintain the alignment of the upper and/or lower anterior teeth. The device was originally designed as a retainer, but it can also be used for tooth movement and correction of minor overlaps or irregularity of the anterior teeth. It was originally described by Philippe ( Fig. 9.17 ).13 , 17 The system is also known as a two-dimensional lingual bracket, and does not provide torque control. All of the archwires are round and will only provide derotation, intrusion, or extrusion, or changes in angulation. It is not possible to apply torque, as there is no rectangular slot. In most cases, anterior alignment relapse is usually confined to small in-out discrepancies and rotations and this can be easily treated with this appliance. Due to its two-dimensionality, a universal bracket can be used on all teeth, which may lead to reduced inventory. The brackets are individualized by modifying their position on individual teeth. Figs. 9.18–9.21 show clinical applications for bracket placement and ligation of an archwire.
The advantage of this concept is that it is possible to use the appliance as a retainer after successful alignment (see Case Study 9.5). To convert the appliance to a retention device, the last wire, usually 0.018 stainless steel, remains in the brackets and is then permanently locked into the individual brackets using a fluoride-containing, flowable composite.
The overall height of the bracket is only 1.4 mm, and patient comfort is improved in comparison with other lingual brackets, which are usually thicker and wider. The wearing comfort is similar to that of a fixed retainer, as the size is very similar.
It is widely known that even fixed retainers allow slight movement of contact points from their original position. With a SOX retainer, it is possible to reopen the retainer and adjust the archwire to correct very minor relapse or tooth movement; especially in adults, where long-term retention appears to be indicated. Many adult patients who have undergone orthodontic treatment experience postorthodontic changes in the alignment of the front teeth in particular. The range of retainers available today may offer these patients the reliable long-term retention they were hoping for after their original orthodontic treatment.
Case Study 9.5 (Fig. 9.22)
Patient: D.H., female, age 18.
Diagnostic records: models, panoramic radiograph, lateral cephalometric radiograph, intraoral/extraoral photographs.
Main findings: late anterior crowding.
Treatment aims: esthetic alignment of the maxillary and mandibular anterior teeth.
Appliances: two-dimensional lingual brackets, IPR.
Archwire sequence: buccal 0.010 SE, 0.012 SE and 0.016 SE preformed lingual archwires, custom-bent 0.016 SS lingual archwire.
Alternative treatment strategy: n/a.
Active treatment time: 6 months. Retention: bonded retainer.
Lingual surfaces that are difficult to reach (due to crowding and/or rotation of teeth) can often be bonded with a reduced-width two-dimensional lingual bracket.
It is recommended to initiate movement using 0.010 superelastic archwire, which we use for buccal alignment as well.
It is often advisable to induce tooth movement by incorporating the first and second premolars in the fixed appliance. We tend to use a high-flow composite for adhesion of the wire, without the need for bracket placement on these teeth.