Periodontal Ligament
Pronunciation: pair-ee-oh-DON-tal LIG-ah-ment
The dense fibrous connective tissue that occupies the space between the root cementum and the alveolar bone, anchoring the tooth in its socket and absorbing occlusal forces.
Full Definition
The periodontal ligament (PDL) is composed principally of collagen fibres arranged in functional groups — oblique, horizontal, alveolar crest, apical, and interradicular — that anchor into cementum and alveolar bone via Sharpey's fibres. Beyond its supportive role, the PDL contains sensory receptors, vascular supply, and progenitor cells essential for repair and regeneration. Radiographically, the PDL space appears as a thin radiolucent line around the root; widening of this space may indicate trauma, parafunctional forces, or pathology. Editors must ensure 'PDL' is defined at first use and must not confuse 'periodontal ligament' with 'periodontium,' the broader term encompassing all supporting tissues. The older term 'peridental membrane' is deprecated.
Usage
Usage note: Abbreviate as 'PDL' after first use. The deprecated synonym 'peridental membrane' should be flagged and replaced. Do not use 'periodontal ligament' and 'periodontium' interchangeably; the PDL is one component of the periodontium.
In Context
- "Radiographic widening of the periodontal ligament space at the apex of tooth 21 suggested occlusal trauma." — Periodontal radiographic report
- "The PDL contains pluripotent progenitor cells that are harnessed in guided tissue regeneration procedures." — Periodontal regeneration research paper