2026 ICD-10-CM Diagnosis Code K04.3Abnormal hard tissue formation in pulp

ICD-10-CM Codes›K00–K95›K00-K14›K04

ICD-10-CM K04.3
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K04.3 is a billable ICD-10-CM diagnosis code for abnormal hard tissue formation in pulp. 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. 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
K04.3
Billable Status
Yes — Valid for Submission
Code Describes
Abnormal hard tissue formation in pulp
Short Description
Abnormal hard tissue formation in pulp
Same as the full description in the CMS dataset.
Parent Code
K04
Diseases of pulp and periapical tissues

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK00-K14Diseases of oral cavity and salivary glands
CategoryK04Diseases of pulp and periapical tissues
This CodeK04.3Abnormal hard tissue formation in pulp

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abnormal hard tissue formation in pulp
  • Calcific metamorphosis of pulp of tooth
  • Obliteration of root canal of tooth due to abnormal mineralization of tooth pulp
  • Pulp degeneration
  • Secondary dentin

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Secondary or irregular dentine

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.

    • Abnormal, abnormality, abnormalities
      • hard tissue formation in pulp (dental)
    • Anomaly, anomalous(congenital) (unspecified type)
      • hard tissue formation in pulp
    • Dentin
      • irregular (in pulp)
    • Dentin
      • secondary (in pulp)
    • Irregular, irregularity
      • dentin (in pulp)
    • Secondary
      • dentin (in pulp)

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

Clinical InformationClinical

  • Abnormal Hard Tissue Formation in Pulp

    development of hard tissue in the inner substance of the tooth where blood vessels, lymphatic, and nerve tissue is normally found.

  • Pulp Degeneration

    deterioration of the normal pulp tissue.

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 K04.3 to ICD-9-CMHistory

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

ICD-9-CM
522.3 Abn hard tiss-tooth pulp
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 K04.3Overview

Is K04.3 (Diseases of pulp and periapical tissues) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report abnormal hard tissue formation in pulp on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does K04.3 group to?

When abnormal hard tissue formation in pulp 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 K04.3?

Under the General Equivalence Mappings, abnormal hard tissue formation in pulp converts to ICD-9-CM 522.3 (abn hard tiss-tooth pulp). 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.