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References

Renfroe EWMichigan: Edward Bros; 1960
Levy-Bercowski D, Abreu A, DeLeon E, Looney S, Stockstill J, Weiler M, Santiago PE One-step conversion of a banded expander to a transpalatal bar. J Clin Orthod. 2007; 41:(5)
Pellegrini P Conversion of a rapid palatal expander to a transpalatal arch. J Clin Orthod. 2009; 43
Kothari A Quick conversion of an expander to a transpalatal arch. J Clin Orthod. 2011; 45

Tricks of the trade - soldering made easy

From Volume 8, Issue 4, October 2015 | Pages 144-145

Authors

Ashima Valiathan

BDS (Pb), DDS, MS(USA)

Professor and Head, Director of PG Studies, Department of Orthodontics, Manipal College of Dental Sciences, Adjunct Professor of Orthodontics, Case Western Reserve University, Ohio, Cleveland, USA

Articles by Ashima Valiathan

Article

Soldering, to join wire components, and the placement of hooks and stops on archwires form an essential part of orthodontic practice (Figure 1). Though easy to perform, heating the wire component to high temperatures for a long duration results in the annealing of wire, which increases the appointment time and leads to frustration on the part of clinician and patient. This article showcases a technique to improve the soldering without annealing the wire component and suggests its application in clinical situations.

Figure 1. Hooks spot welded to two archwires.

As against the norm of using the reducing zone (Figure 2) of the flame (blue zone), it is suggested that the non visible region (Figure 3) of the flame is used to achieve soldering. The blue zone avoids oxidation but the amount of heat generated is too great to achieve soldering without annealing the wire (Figure 4). However, the non visible region provides sufficient heat to achieve soldering.1

Figure 2. Reducing zone of flame used.
Figure 3. Non-visible zone of flame used.
Figure 4. Wire annealed and distorted in the former.

Clinical applications

Conversion of a rapid maxillary expander into transpalatal arch

After rapid maxillary expansion, it is common practice to secure the expansion screw and leave the appliance passively in place for several months. The clinician may then place a removable plate, a Hawley or Essix retainer, or a transpalatal arch (TPA) to maintain the transverse correction. Many authors2,3,4 have described techniques for converting a banded expander to a transpalatal arch; here is an alternative technique.

  • Before placing the Hyrax-type expander fabricate a TPA in 0.036” stainless steel;
  • Solder the TPA to only one arm of the expander allowing the other end to be free prior to the cementation (Figure 5a);
  • After the expansion, make minor adjustments to the free arm so that it adapts well to the expander wire;
  • Then, carefully place light cure acrylic resin to secure the free end to the expander so that the acrylic covers only the wire component;
  • Cut away the expansion screw.
    • Figure 5. (a) Solder the TPA to only one arm of the expander. (b) The final outcome.

    The final outcome is shown in Figure 5b.

    Conversion can be performed chairside hence bypassing all laboratory work.

    Repair of a fractured Hawley retainer

    Patients often present with broken soldered wire components of removable appliances such as a Hawley retainer. It is difficult to stabilize wire components for soldering without models which would involve an additional impression. A simple technique to repair the broken components is presented:

  • Approximate the wire component to the correct position and tie it with thin ligature wire which is routinely used for ligation of archwires in brackets (Figure 6a, b);
  • Cut the excess ligature;
  • Check the fit of the appliance in the patient's mouth (Figure 7a, b);
  • Solder the wire component, and trim it to make it smooth (Figure 8).
    • Figure 6. (a, b) Hawley's retainer with broken wire component.
    Figure 7. (a, b) After ligature tie.
    Figure 8. After soldering and placement.