**Cementum Formation**

**Core Concept**
Cementum is a specialized bone-like tissue covering the root of a tooth, anchoring it to the surrounding alveolar bone through the periodontal ligament. Its formation is a complex process involving the coordinated action of various cell types and molecular signals.

**Why the Correct Answer is Right**
Cementum formation occurs through a process called intramembranous ossification, where cementoblasts differentiate from the reduced enamel epithelium and adjacent periodontal ligament cells. These cementoblasts then proliferate and deposit a matrix of collagen and minerals, eventually forming the acellular or cellular cementum. This process is mediated by growth factors such as bone morphogenetic proteins (BMPs) and transforming growth factor-beta (TGF-β).

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because cementum formation is not primarily through endochondral ossification, which is a process typically seen in the development of long bones.
**Option B:** This option is incorrect because cementum does not form through the process of odontogenesis, which is the development of the tooth itself.
**Option C:** This option is incorrect because cementum formation is not a continuous process, but rather a dynamic one involving the coordinated action of various cell types and molecular signals over time.

**Clinical Pearl / High-Yield Fact**
It's essential to note that cementum is unique in that it does not contain blood vessels or nerves, making it a relatively avascular and aneural tissue.

**Correct Answer: D. Cementum formation is seen through intramembranous ossification.**