[Archwire segmentation: a solution to the problems involved in treating atypical cases]

Asymmetrical orthodontic cases frequently prove very difficult to correct. Anchorage mini-screws are often needed to treat these cases when the malocclusion is of maxillary origin. Nonetheless, a precise biomechanical assessment must be made to avoid undesirable sideeffects resulting from the mechanics used. Whether one uses a continuous or a segmented archwire, adverse events can occur and must be planned for in order to contain them.

The authors will first give an overview of the possible undesirable effects using the continuous arch technique and the principles underlying the segmented archwire technique. Various clinical cases will also be described to support their argument.

The advantage of the segmented techniques lies in the precision and speed of the movements obtained in the three dimensions of space. However, they can also present major drawbacks. In practice, these techniques seem best-suited to complex atypical cases, and particularly cases involving asymmetry of the frontal and transverse planes.