2026 ICD-10-CM Diagnosis Code K04.1Necrosis of pulp

ICD-10-CM Codes›K00–K95›K00-K14›K04

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

K04.1 is a billable ICD-10-CM diagnosis code for necrosis of 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. Coders also document this condition as mummified pulp. 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
K04.1
Billable Status
Yes — Valid for Submission
Code Describes
Necrosis of pulp
Short Description
Necrosis of 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 CodeK04.1Necrosis of pulp

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Mummified pulp
  • Necrosis of the pulp

Tabular List NotesGuidance

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

Inclusion Terms

  • Pulpal gangrene

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.

    • Gangrene, gangrenous(connective tissue) (dropsical) (dry) (moist) (skin) (ulcer)
      • pulpal (dental)
    • Gangrene, gangrenous(connective tissue) (dropsical) (dry) (moist) (skin) (ulcer)
      • tooth (pulp)
    • Necrosis, necrotic(ischemic)
      • dental pulp
    • Necrosis, necrotic(ischemic)
      • pulp (dental)
    • Putrescent pulp(dental)

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 K04.1 to ICD-9-CMHistory

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

ICD-9-CM
522.1 Necrosis of 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 K04.1Overview

Is K04.1 (Diseases of pulp and periapical tissues) a billable code?

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

What MS-DRG does K04.1 group to?

When necrosis of 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 K04.1?

Under the General Equivalence Mappings, necrosis of pulp converts to ICD-9-CM 522.1 (necrosis of 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.