Cementum

Cementum is a specialized mineralized connective tissue covering the entire root surface of a tooth, extending from the cementoenamel junction to the root apex. Cementum is relatively thin, ranging from approximately 20 to 50 micrometers cervically to 150 to 200 micrometers at the apex. Its primary function is to provide the attachment surface for the periodontal ligament's Sharpey fibers, which embed into the cementum on the root side and into the alveolar bone on the socket side, anchoring the tooth within its bony socket. Cementum is classified into two types: acellular (primary) cementum, covering the cervical two-thirds of the root and deposited during development, and cellular (secondary) cementum, deposited at the apical third and continuing to form throughout life.

The clinical significance of cementum relates to its role in periodontal health, disease, and treatment. In periodontal disease, bacterial endotoxins from subgingival plaque become embedded in the cementum surface, perpetuating the inflammatory response. Removing this contaminated layer is a key objective of scaling and root planing, where clinicians debride the root surface to create a biologically compatible surface promoting periodontal ligament reattachment. Unlike enamel, cementum can regenerate, enabling guided tissue regeneration procedures to achieve new cementum formation on previously diseased root surfaces. When recession exposes cementum above the gumline, the root becomes susceptible to caries and sensitivity because cementum is softer and more soluble than enamel.

For billing staff, cementum conditions are not coded as standalone diagnoses but support the clinical rationale for periodontal procedure codes. Scaling and root planing codes describe instrumentation of root surfaces, including removal of diseased cementum and smoothing of remaining root structure. Documenting root surface conditions such as calculus, roughness, or endotoxin contamination strengthens the narrative supporting periodontal treatment codes. When regenerative procedures are performed, the billing team should document the pre-treatment root surface condition and regenerative materials used to support higher-value procedure codes and obtain pre-authorization approval.