periodontium

The periodontium is the group of tissues that surround and support the teeth in the jaw. It includes the gingiva (gums), periodontal ligament, cementum, and alveolar bone, as well as the junctional epithelium and the gingival connective tissue that seal around the tooth.

The gingiva comprises the marginal (free) gingiva and the attached gingiva, forming the gingival sulcus between the free margin and the tooth. The mucogingival junction marks the boundary with the alveolar mucosa. The gingiva protects underlying tissues and participates in the immune defense of the oral cavity.

The periodontal ligament is a dense fibrous connective tissue that connects cementum to the alveolar bone. It contains collagen fiber bundles (including groups that run obliquely, horizontally, vertically, and apically) and supplies nutrients, sensation, and remodeling capacity. It cushions occlusal forces and provides proprioceptive feedback. Sharpey fibers anchor the ligament to cementum and to the alveolar bone.

Cementum covers the tooth root and anchors the periodontal ligament to the tooth. It varies in cellularity along the root, with acellular cementum typically present near the crown and cellular cementum more apically. The alveolar bone forms the socket that houses the tooth root and undergoes continuous remodeling in response to functional loads and periodontal health.

Health and disease: a healthy periodontium maintains tooth stability and a barrier against infection. Plaque biofilm can trigger gingivitis, an inflammation of the gingiva. If inflammation progresses to periodontitis, connective tissue and bone are lost, leading to pocket formation, recession, mobility, and potential tooth loss. Risk factors include smoking, diabetes, and poor oral hygiene; management emphasizes plaque control and, when needed, periodontal therapy.