W arch

W Arch

The W Arch or Porter appliance is fabricated using .036 wire. The appliance is activated by opening the apices and can be easily adjusted to provide more anterior or posterior expansion. The appliance should be manually opened 3-4 mm before insertion to provide proper forces. The expansion should continue at a rate of 2mm per month until the crossbite is overcorrected.

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Treatment & Care

There are two ways to activate the W arch before placing it in the mouth. Ricketts et al. (1979) originally suggested that operators activate the appliance with three-pronged pliers to incorporate expansion and molar-rotating force. Another method proposed by Kholoki (1995) employs an arch form chosen from a pentamorphic chart that serves as a pattern for regulating the W Arch.

This appliance should be cleaned every day with toothpaste and a soft toothbrush, morning and night. Encourage the patient to give sufficient time to clean thoroughly around the appliance, gums, teeth, and bands to maintain proper hygiene and prevent inflammation. 3 minutes is recommended.


  • Wire: American Orthodontics Chromium Cobalt

Attachment & Band options:

  • AO Maximum Retention Bands
  • Leone Web Bands
  • AO .022 Slot w/ Hook
  • AO Headgear and .022 Slot with Hook
  • AO MBT w/hook
  • AO Double Slot w/ Hook