**Core Concept**
The pontic is a prosthetic tooth used in a fixed partial denture (FPD) to replace a missing posterior tooth. The design and characteristics of the pontic are crucial in ensuring the proper distribution of forces and prevention of tissue irritation.

**Why the Correct Answer is Right**
The pontic should be designed to minimize contact with the surrounding soft tissues, particularly the gingiva and the floor of the mouth. A well-designed pontic should have a smooth, rounded surface to prevent irritation and promote healthy tissue adaptation. This is particularly important in the posterior region where the forces of mastication can be significant.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as a pontic should not be designed to contact the gingiva, as this can lead to irritation and inflammation.
**Option B:** This option is incorrect as the pontic should not be designed to be bulky or prominent, as this can lead to tissue irritation and discomfort.
**Option C:** This option is incorrect as the pontic should not be designed to be too narrow or thin, as this can lead to fracture or breakage under occlusal forces.

**Clinical Pearl / High-Yield Fact**
When designing a pontic, it is essential to consider the principles of tissue adaptation and the distribution of forces to ensure a successful outcome. A well-designed pontic can promote healthy tissue adaptation and prevent complications such as irritation and inflammation.

**Correct Answer:** D. A pontic should be designed to be smooth and rounded to prevent tissue irritation.