Developments in the Lingual Technique
There were two important developments that were pivotal in improving results using the Lingual Technique: the manufacture of special lingual braces and the development of indirect bonding techniques along with the appropriate laboratory process. As the lingual surfaces of the teeth are anatomically very different to the labial ones, numerous complicated bends have to compensate for these differences whenever labial braces are employed and this drives both the patient and the therapist to despair and can also make the treatment unacceptably lengthy. However, it is now possible to order special lingual braces from a dozen different suppliers within the European market.
The Laboratory Process
But something that is at least as important as the braces themselves is the laboratory process. When the first experiments with lingual braces started, orthodontists simply stuck them directly into the mouth. But the lingual surfaces are more difficult to see and to access than the labial ones and, furthermore, the anatomy of the labial surfaces exhibits significant variations.
For these reasons, the direct bonding technique often results in braces being positioned so imprecisely that a disproportionate amount of work then becomes necessary during the final, ‘finishing’ phase of treatment. This is why using indirect bonding to fix the braces has become the generally accepted practice. The indirect bonding technique means that the braces are first positioned on a jaw model in an orthodontic laboratory. Then a dental transfer plate is made with the help of which the braces can be quickly and precisely stuck into the mouth. The laboratory process for the indirect bonding technique usually involves using the original (malocclusion) model by carving out the teeth and a wax setup to make an ideal setup to determine the position of the brace brackets so exactly that they are all leveled and can then be joined together by a wire that will only require minimal bending. The positions of the brackets can then be transferred from the setup to the malocclusion model and the brackets are stuck on. Finally, transfer jigs are produced to enable the brackets to be precisely fixed into the patient’s mouth in the exact same positions that were determined during the laboratory process.
The jigs are retained for the entire duration of the treatment so that even broken brackets can be repositioned at any time without any significant loss of accuracy. The laboratory process can basically be carried out within the orthodontic practice, although most people using the lingual technique usually call on the services of industrial laboratories which can work in a more routine and structured way because of the number of units involved. The latest development involving the use of a computer-controlled bending machine to supply the therapist with pre-bent, customised wires is only available from highly specialised industrial laboratories. In every case, the positioning of the brackets in a laboratory is the key to providing sensible treatment and achieving a high-quality result.