**Core Concept**
Multiple pulp stones are associated with a condition characterized by the formation of calcified structures within the dental pulp, often in response to chronic irritation or inflammation. This phenomenon is linked to the body's attempt to repair and protect the tooth from further damage.

**Why the Correct Answer is Right**
The presence of multiple pulp stones is a hallmark of a specific dental condition. These stones are typically composed of calcium hydroxyapatite and are formed through a process of calcification within the dental pulp. This can occur due to various factors, including trauma, caries, or other forms of chronic irritation. The formation of pulp stones is often seen as a protective mechanism, as it helps to reduce the sensitivity and inflammation within the affected tooth.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because pulp stones are not typically associated with conditions affecting the periodontal ligament.
**Option B:** This option is incorrect because periapical cysts are characterized by a fluid-filled sac surrounding the root of a tooth, rather than the formation of calcified structures within the pulp.
**Option C:** This option is incorrect because pulp stones are not a characteristic feature of pulp necrosis, which is typically associated with a more severe and irreversible damage to the pulp tissue.

**Clinical Pearl / High-Yield Fact**
It is essential to recognize that multiple pulp stones can be a sign of chronic dental irritation, and addressing the underlying cause is crucial to preventing further damage and promoting optimal oral health.

**Correct Answer:** D. Ehlers-Danlos syndrome