## **Core Concept**
The question tests knowledge of oral pathology, specifically odontogenic cysts, which are jaw cysts derived from the epithelial remnants of tooth development. Odontogenic cysts are broadly classified into developmental and inflammatory types. The most common type among these is of developmental origin.

## **Why the Correct Answer is Right**
The **radicular cyst**, also known as a periapical cyst, is the most common odontogenic cyst. It is of inflammatory origin, arising as a result of pulp necrosis and infection, typically following dental caries. This cyst develops at the apex of a non-vital tooth and is lined by stratified squamous epithelium. Its pathogenesis involves the proliferation of epithelial cell rests of Malassez in response to inflammation.

## **Why Each Wrong Option is Incorrect**
- **Option A:** While **dentigerous cysts** are indeed odontogenic cysts and are the second most common type, they are specifically associated with the crown of an unerupted tooth, particularly impacted wisdom teeth. They are developmental in origin.
- **Option B:** **Odontogenic keratocysts (OKCs)**, now more commonly referred to as keratocystic odontogenic tumors, are less common and known for their aggressive behavior and potential to be part of the nevoid basal cell carcinoma syndrome (Gorlin syndrome). They are lined by keratin-producing epithelium.
- **Option D:** **Tartar-induced gingival cysts** or **epithelial rests of Malassez cysts** are much less common and not typically categorized among the major types of odontogenic cysts like radicular or dentigerous cysts.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that radicular cysts are often associated with non-vital teeth and are a common cause of jaw cysts. They are usually diagnosed radiographically as a well-defined radiolucency at the apex of a tooth with a necrotic pulp. Treatment often involves endodontic therapy or extraction of the involved tooth, sometimes followed by cyst enucleation.

## **Correct Answer:** D. Radicular cyst.