In Edgewise appliances, what are the slot orientation and dimensions?

• A. Vertical slot on the bracket with a round wire.
• B. Horizontally oriented slot with a 18x24 wire.
• C. Vertical slot (22x28) with a 22x28 wire.
• D. Horizontal slot (22x28 width), with a 22x28 precious metal wire.

Answer: (D)

In Edgewise appliances, tooth movement is achieved by a rectangular archwire seated in a rectangular bracket slot. The slot’s cross‑section and its orientation determine how snugly the wire sits and how effectively it can produce moments to control torque and angulation.

The described setup uses a horizontal slot with a cross‑section of 22 by 28 (0.022 by 0.028 inches) and a matching 22 by 28 rectangular wire, typically made of precious metal. This pairing fills the slot tightly, maximizing control over tooth movement, especially torque, since less play between wire and slot means more precise force transmission. The horizontal orientation refers to how the slot is milled in the bracket so the longer dimension runs across the face, matching the rectangular wire’s cross‑section and enabling proper engagement.

Other options would either imply the wrong slot orientation or mismatched dimensions, reducing engagement and control.