Lingual Technology

The lingual technique is an orthodontic treatment method using fixed appliances composed of brackets and wire archwires. For aesthetic reasons, the brackets in the elaborate lingual technique are bonded to the inner surfaces of the teeth facing the tongue, while in the more common labial technique (brackets are bonded to the outer surface of the teeth) they are positioned in the visible area facing the lip.

Indications (areas of application)

The two methods do not differ in terms of the treatment result, but by the aesthetics during the wearing period of the appliances and the resulting higher technical effort both in the dental laboratory and in bonding the brackets and changing the archwires throughout the orthodontic treatment.

A lingual fixed appliance is used for the following indications, for example:

  • Rotational position of teeth
  • Root tilts
  • Teeth that not only need to be straightened, but physically moved.
  • Treatment of adults
  • Highest aesthetic standards

In terms of patient comfort, the lingual technique is somewhat inferior to the labial technique in that at the beginning of treatment, speech disorders such as lisping and irritation of the tongue may occur due to the narrowed tongue space. Reading exercises for two weeks retrain the tongue muscles. It also has the advantage that, for example, the habit of tongue clenching is broken and gaps between teeth caused by clenching can be closed more easily.

Another disadvantage of the lingual technique also turns out to be an advantage at second glance: lingual brackets disrupt occlusion (any contact between the teeth of the upper and lower jaw) more often than brackets bonded on the outside. Ultimately, however, this releases the teeth from their interlock with the opposing jaw, allowing them to move much more easily than if they were forced back into their original position each time they clenched.

The procedure

The lingual technique is technically complex for both the practitioner and the orthodontic laboratory, due to the poorer accessibility of the lingual surfaces and the smaller distance between brackets on the inner side of the dental arch. In addition, the force application on the lingual side results in biomechanical peculiarities.

The workflow in the lingual technique is as follows:

  • Impressions of the upper and lower jaw.
  • Bite taking, with which the jaws are brought into the correct three-dimensional relationship with each other in the laboratory
  • Making plaster models in the laboratory
  • Set up: the plaster teeth are separated and, set up in an ideal dental arch, fixed in wax;
  • On the inner sides of the plaster teeth are positioned lingual brackets.
  • Production of a transfer splint made of plastic: the brackets remain in the splint in their correct positions; then they are transferred to the patient with the help of the splint
  • Indirect bonding technique: the brackets are bonded in the patient’s mouth after cleaning the teeth and chemical conditioning (to improve the bonding strength) of the enamel; since this is done with the help of the transfer splint, it is called indirect bonding technique. The accuracy in this step greatly affects the treatment result.
  • Insertion of the first guide arch into the slots (notches) of the brackets.

In the further course of several months of fixed treatment, new guide arches are ligated (bonded) at regular intervals in different dimensions and depending on the force applied. Since the lingual space is also difficult to access for this purpose, special self-ligating brackets facilitate the treatment.

To ensure the treatment result, fixed treatment is followed by a long-term retention phase with removable appliances, usually worn at night, and/or fixed retainers (wire on the inside of the incisors).