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W Arch Expander


Appliance Purpose / Function:

The W Arch, or Porter expander is used to expand the posterior segments of the arch, correct bilataral or unilataral cross bites, and help align crowded teeth.

Appliance Components:

  • Bands on the 1st permanent molars
  • W Arch wire

Suggested Materials:

  • Wire: .036 Chromium Cobalt wire or Stainless-Steel
  • .040 Chromium Cobalt tube
  • Silver Solder (Cadmium Free)


  • Laser welding (no solder)
  • Face mask hooks
  • Archwire Tubes
  • Headgear Tubes

Appliance Fabrication Standards:

  • .036 Blue Elgiloy wire or Stainless-Steel
  • Wire should rest 1 – 1.5mm o the soft tissue
  • Approximately 4mm of wire should lay on the band for soldering or welding Lingual bars should extend to the mesial of the cuspids