2026 ICD-10-CM Diagnosis Code K03.9Disease of hard tissues of teeth, unspecified

ICD-10-CM Codes›K00–K95›K00-K14›K03

ICD-10-CM K03.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K03.9 is a billable ICD-10-CM diagnosis code for disease of hard tissues of teeth, unspecified. 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 dental caries secondary to acquired defects of tooth structure. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Any dental condition including traumatic injury; Caries, periodontitis, and other preventable dental conditions; and Disorders of teeth and gingiva.

Code Identity

ICD-10-CM Code
K03.9
Billable Status
Yes — Valid for Submission
Code Describes
Disease of hard tissues of teeth, unspecified
Short Description
Disease of hard tissues of teeth, unspecified
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 CodeK03.9Disease of hard tissues of teeth, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Dental caries secondary to acquired defects of tooth structure
  • Disorder of hard tissues of teeth
  • Secondary dental caries associated with local or systemic factors

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.

    • Disease, diseased
      • 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 DEN003
Caries, periodontitis, and other preventable dental conditions
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 K03.9 to ICD-9-CMHistory

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

ICD-9-CM
521.9 Hard tiss dis teeth NOS
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 K03.9Overview

Is K03.9 (Other diseases of hard tissues of teeth) a billable code?

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

What MS-DRG does K03.9 group to?

When disease of hard tissues of teeth, unspecified 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 K03.9?

Under the General Equivalence Mappings, disease of hard tissues of teeth, unspecified converts to ICD-9-CM 521.9 (hard tiss dis teeth NOS). The mapping is a direct match.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.