Envelope flaps are characterized by the absence of which releasing incision?

• A. Vertical releasing incision
• B. Horizontal releasing incision
• C. Diagonal releasing incision
• D. No releasing incision

Answer: (A)

In flap design, releasing incisions free tissue so a flap can be mobilized. An envelope flap achieves access without any vertical releasing incisions—the flap is raised by undermining and a curved, envelope-like incision around the tooth rather than by splitting tissue with vertical cuts. This preserves blood supply to the flap and the interdental papilla, and it avoids the scar and tissue disruption that vertical releases can cause. Horizontal or diagonal releasing incisions aren’t part of the envelope flap design, which hinges on the absence of vertical releasing incisions.