Читать книгу Orthodontic Treatment of Impacted Teeth - Adrian Becker - Страница 51

TMA cantilevers (0.018 in. TMA) can be welded to a TMA TPA (0.032 in. × 0.032 in. or 0.032 in. round) and used for erupting palatally displaced canines (Figure 3.3a, b). Possible side effects resemble those created by buccally engaged cantilevers and should be countered with a stiff rectangular continuous bypass archwire.

Fig. 3.2 (a) The passive cantilever, made of rectangular wire, extends from the molar auxiliary tube and crosses to the lingual through the space in the canine site. The anterior end is occlusal to the canine. N.B. A stepped bypass is introduced into the continuous main arch. (b, c) The base arch is stepped upwards to permit unobstructed extrusion and to allow the cantilever to cross to the lingual. (d) Activation of the cantilever creates two moments at the molar to rotate it mesio‐lingually and in a crown mesial and root distal direction (in the sagittal plane).

This is arguably the best method for extrusion and distalization of palatally impacted canines that can be accomplished.