**Core Concept**
The attached gingiva is a crucial structure in oral health, providing a seal around the teeth and protecting the underlying bone. The width of attached gingiva is essential for maintaining periodontal health and preventing conditions like gingival recession. Various surgical techniques, including flap procedures, can be used to manage periodontal defects.

**Why the Correct Answer is Right**
The correct answer is related to the type of flap procedure that does not increase the width of attached gingiva. A **free gingival graft (FGG)** is a type of flap procedure that involves taking a graft of gingival tissue from one area of the mouth and transplanting it to another area. This procedure is used to increase the width of attached gingiva, but it does not increase the width of the attached gingiva in the donor site. Instead, it relies on the growth of new tissue to cover the defect.

**Why Each Wrong Option is Incorrect**
**Option A:** A **pedicle graft (PG)** is a type of flap procedure that involves taking a graft of gingival tissue from one area of the mouth and transplanting it to another area while maintaining a connection to the underlying bone. This procedure can increase the width of attached gingiva in both the recipient and donor sites, making it an incorrect answer.

**Option B:** A **connective tissue graft (CTG)** is a type of flap procedure that involves taking a graft of connective tissue from the palate and transplanting it to another area. This procedure can increase the width of attached gingiva, but it is not the answer because the question specifically asks for a procedure that does not increase the width of attached gingiva.

**Option C:** A **subepithelial connective tissue graft (SCTG)** is a type of flap procedure that involves taking a graft of connective tissue from the palate and transplanting it to another area. This procedure can increase the width of attached gingiva, making it an incorrect answer.

**Clinical Pearl / High-Yield Fact**
When performing surgical procedures to increase the width of attached gingiva, it is essential to consider the growth potential of the recipient site and the donor site. The FGG procedure is a useful option when the recipient site has adequate growth potential, but it may not be suitable for areas with limited growth potential.

**Correct Answer:** D.