Periodontium

The periodontium refers to the specialised supporting and investing tissues of the teeth that maintain tooth stability within the alveolar processes of the maxilla and mandible. It consists of four principal components: the gingiva, periodontal ligament, cementum, and alveolar bone. Together, these structures function to support the teeth, absorb masticatory forces, provide sensory feedback, and maintain periodontal health.

1. Gingiva

The gingiva, commonly known as the gums, is a pink-coloured keratinised mucosa that surrounds the cervical portions of the teeth and covers the alveolar processes. It forms a protective seal around the teeth through specialised junctional epithelial cells located within the gingival sulcus. This junctional epithelium acts as an important barrier against mechanical trauma and microbial invasion while maintaining attachment between the tooth surface and oral epithelium.

2. Periodontal ligament

The periodontal ligament (PDL) is a specialised fibrous connective tissue situated between the cementum and alveolar (jaw) bone. It contains bundles of collagen fibres that anchor the tooth root to the alveolar socket and act as shock absorbers during mastication. The PDL also contains blood vessels, lymphatics, and sensory nerve fibres important for proprioception and pain sensation.

3. Cementum

Cementum is a calcified connective tissue covering the surface of the root-portion of the tooth. It provides attachment for periodontal ligament fibres and contributes to tooth support and repair.

4. Alveolar bone

The alveolar bone forms the tooth sockets (alveoli) and supports the roots of the teeth. Continuous remodelling of the alveolar bone occurs in response to functional forces applied during mastication and orthodontic movement.

Blood supply and innervation

The periodontium receives a rich vascular supply from branches of the external carotid artery, including the superior and inferior alveolar, greater palatine, buccal, submental, and sublingual arteries. Sensory innervation is primarily provided by branches of the maxillary and mandibular divisions of the trigeminal nerve.

Clinical correlate

Clinically, periodontal diseases such as gingivitis and periodontitis can result in inflammation, connective tissue destruction, alveolar bone loss, tooth mobility, and eventual tooth loss.