ICD-10 Code K08.421 – Partial loss of teeth due to periodontal diseases, class I (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code K08.421 – Partial loss of teeth due to periodontal diseases, class I
What it is
This code identifies partial loss of teeth caused by periodontal disease, limited to class I severity. Use it when documentation shows tooth loss is linked to gum and supporting-structure disease, not trauma or caries.
Clinical signs
Typical findings include missing teeth with a history or diagnosis of periodontal disease. Clinical features vary; refer to documentation for the extent of tooth loss and the recorded class.
When to use this code
Use K08.421 when the provider documents partial tooth loss due to periodontal disease and specifies class I. It fits dental or medical records that clearly connect the missing teeth to periodontal destruction. Check documentation if the cause or class is not stated.
Do not use for
Do not use this code for tooth loss from injury, dental caries, or congenital absence. If the record does not confirm periodontal disease as the cause, code the documented condition instead.
Coding tip
Verify both the cause and the class designation in the note before assigning K08.421.