Quick Conversion of an Expander to a Transpalatal Arch
After rapid palatal expansion, a removable plate, a Hawley or Essix retainer, or a transpalatal arch is usually placed in the maxilla to retain the correction for 100 days or longer. Each of these appliances requires an impression and a follow-up appointment for placement.
Other authors have previously described techniques for converting a banded expander to a transpalatal arch without the need for impressions or a delivery appointment.1,2 I suggest making conversion even faster by using the following technique:
1. Before placing the Hyrax-type expander, solder lengths of .040" stainless steel wire to the palatal surfaces of each posterior expansion leg.
2. Bend the inner ends of the wires to follow the palatal surfaces on each side of the expansion screw (A) as close to the screw surface as possible, thus avoiding contact with the palate (B).
3. After expansion (C), deband the appliance; carefully straighten the wire extensions, then solder them together to form a transpalatal arch (D).
4. Cut away the expansion screw (E) and recement the transpalatal arch in the mouth (F).
This modified conversion technique requires only a single solder joint, minimizing both lab time and chairtime. I would like to see expansion appliances manufactured with built-in extension legs to make the procedure even more convenient.