- Shape of the lingual arches
Basically, in Lingual Orthodontics, there are two kinds of lingual arches: mushroom and straight-wire. The presence of the bends between premolars and canines (called disto-canine bends) is depending on the profile of the lingual brackets, the height of the brackets, and of the dental volume of the patient. The bend (also called “bridge disto-canine”) is a well-known bend compensation in Lingual Orthodontics (L.O.) and both its dimension and its exact sagittal placement is customized for each patient.
Usually, the anterior curve of lingual arches is providing by the manufacturer of the brackets.
The posterior segments of the arch are totally straight and divergent to each other. In occlusal view, the interproximal contact between canines and premolars is the reference to get bends is the interproximal contact (fig.1).
Figure 1. The scheme represents the correct position of disto-canine bend on the mushroom arch. The posterior segment does not appear curved.
- Bends in Octopus Lingual Braces
We have defined specific templates (CLICK here to access the template pdf file) that show three basic sizes of lingual arches to Octopus Lingual Braces (small, medium, and large, Fig. 2).It is import to point that the size and the exact placement of the disto-canines bends are defined according to each case.
The digital placement of Octopus L allows getting wires with or without disto-canines bends. Both Doctors and technicians will define if the case will be better with bends or not. In all cases, always the maintenance of minimum space between the lingual base of the brackets and the lingual surface is the best option. We are noting that the frequency of the straight-wire arch is higher on the lower and the mushroom arches, on the upper jaws.
- Additional bends
Not so rarely, some additional bends are necessary for lingual orthodontics. The most common bend (after disto-canines) is an off-set, that is present on upper second premolars (frequently, the palatine cusped is too small, Fig. 2). Secondly, there are frequent in-sets bends on the mesial of the first lower molars.
Figure 2. On the left, the scheme represents the correct off-sets bends on the upper arch. Note the small lingual cusped of second premolar. In the figure on the right, we can see the inset molar.