2026 ICD-10-CM Diagnosis Code K03.5Ankylosis of teeth

ICD-10-CM Codes›K00–K95›K00-K14›K03

ICD-10-CM K03.5
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K03.5 is a billable ICD-10-CM diagnosis code for ankylosis of teeth. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 157 through 159. Coders also document this condition as ankylosis of tooth. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Any dental condition including traumatic injury, Disorders of teeth and gingiva, and Nontraumatic dental conditions.

Code Identity

ICD-10-CM Code
K03.5
Billable Status
Yes — Valid for Submission
Code Describes
Ankylosis of teeth
Short Description
Ankylosis of teeth
Same as the full description in the CMS dataset.
Parent Code
K03
Other diseases of hard tissues of teeth

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK00-K14Diseases of oral cavity and salivary glands
CategoryK03Other diseases of hard tissues of teeth
This CodeK03.5Ankylosis of teeth

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Ankylosis of tooth

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Ankylosis(fibrous) (osseous) (joint)
      • dental
    • Ankylosis(fibrous) (osseous) (joint)
      • tooth, teeth (hard tissues)

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR DEN001
Any dental condition including traumatic injury
Default principal diagnosis: inpatient No · outpatient No
CCSR DIG002
Disorders of teeth and gingiva
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR DEN002
Nontraumatic dental conditions
Default principal diagnosis: inpatient No · outpatient No

Patient EducationClinical

Tooth Disorders

Your teeth are made of a hard, bonelike material. There are four parts:

The full article covers:

  • What are teeth?
  • What are tooth disorders?
  • What causes tooth disorders?
  • What are the symptoms of tooth disorders?
  • How are tooth disorders diagnosed?
  • What are the treatments for tooth disorders?
  • Can tooth disorders be prevented?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert K03.5 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
521.6 Ankylosis of teeth
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About K03.5Overview

Is K03.5 (Other diseases of hard tissues of teeth) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report ankylosis of teeth on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does K03.5 group to?

When ankylosis of teeth is the principal diagnosis on an inpatient stay, it groups to MS-DRG 157, 158, 159, with relative weights from 0.7085 to 1.7168 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of K03.5?

Under the General Equivalence Mappings, ankylosis of teeth converts to ICD-9-CM 521.6 (ankylosis of teeth). The mapping is a direct match.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.