Biological Width
The combined dimension of the junctional epithelium and the supracrestal connective tissue attachment coronal to the alveolar bone crest.
Full Definition
Biological width refers to the approximately 2 mm of tissue—roughly 1 mm of junctional epithelium and 1 mm of supracrestal connective tissue—that constitutes the soft-tissue seal between the base of the gingival sulcus and the crest of alveolar bone. Violation of biological width by subgingival restorative margins, crown preparations, or implant components triggers chronic inflammation, bone loss, and gingival recession. The term has largely been replaced by 'supracrestal tissue attachment' (STA) in contemporary periodontal classification (2017 World Workshop), though 'biological width' remains widely used in restorative and prosthodontic literature. Editors should note both terms and flag inconsistencies within a manuscript.
Usage
Usage note: The 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases recommends 'supracrestal tissue attachment (STA)' over 'biological width'. Both spellings 'biologic width' (American) and 'biological width' (British) are acceptable; apply consistently.
In Context
- "The crown margin was placed 2 mm above the alveolar crest to respect the biological width and prevent crestal bone loss." — Crown preparation restorative case report
- "Violation of biological width by the subgingival filling explained the persistent inflammation at the mesial aspect of the tooth." — Periodontal assessment report