**Question:** Width of the periodontal ligament is least at

A. mesial
B. distal
C. buccal
D. lingual

**Core Concept:** The periodontal ligament (PDL) is a connective tissue that connects the cementum of the tooth to the alveolar bone. It plays a crucial role in maintaining the tooth's position in the alveolar socket and transmitting forces generated during mastication. The PDL has a variable width, which varies according to the tooth's location and direction of force application.

**Why the Correct Answer is Right:** The width of the periodontal ligament is least at the point of contact between two teeth, where the force application is most concentrated during mastication. In this scenario, the width of the PDL minimizes the stress concentration, preventing damage to the tooth and supporting structures.

**Why Each Wrong Option is Incorrect:**

A. Mesial: The width is not least at the mesial aspect (towards the middle of the tooth) as the PDL is wider in this area to distribute the force over a larger surface area.
B. Distal: The width is not least at the distal aspect (towards the tooth's tip) as the force is less in this region compared to the point of contact.
C. Buccal: The width is not least at the buccal aspect (towards the cheek) as the force is less in this area compared to the point of contact.
D. Lingual: The width is not least at the lingual aspect (towards the tongue) as the force is less in this area compared to the point of contact.

**Clinical Pearl:** Understanding the variation in periodontal ligament width helps in assessing the tooth's health and stability. In cases of periodontal diseases or trauma, the width of the PDL can be affected, providing valuable diagnostic information for practitioners.