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What is Which of the following pontic designs require surgical procedure? and explain in detail?
The ovate pontic is the pontic design that is most esthetically appealing. Its convex tissue surface resides in a soft tissue depression or hollow in the residual ridge, which makes it appear that a tooth is literally emerging from the gingiva. 
Careful treatment planning is necessary for successful results. Socket-preservation techniques should be performed at the time of extraction to create the tissue recess from which the ovate pontic form will appear to emerge. 
For a preexisting residual ridge, surgical augmentation of the soft tissue is typically required. When an adequate volume of ridge tissue is established, a socket depression is sculpted into the ridge with surgical diamonds, electrosurgery, or a dental laser.

Key Concept:
For a preexisting residual ridge, surgical augmentation of the soft tissue is typically required. When an adequate volume of ridge tissue is established, a socket depression is sculpted into the ridge with surgical diamonds, electrosurgery, or a dental laser.