2026 ICD-10-CM Diagnosis Code K04.01Reversible pulpitis

ICD-10-CM Codes›K00–K95›K00-K14›K04

ICD-10-CM K04.01
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K04.01 is a billable ICD-10-CM diagnosis code for reversible pulpitis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 11 through 13, 157 through 159. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 229 closely related codes. 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
K04.01
Billable Status
Yes — Valid for Submission
Code Describes
Reversible pulpitis
Short Description
Reversible pulpitis
Same as the full description in the CMS dataset.
Parent Code
K04.0
Pulpitis

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK00-K14Diseases of oral cavity and salivary glands
CategoryK04Diseases of pulp and periapical tissues
This CodeK04.01Reversible pulpitis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abscess of oral soft tissue
  • Acute pulpitis
  • Asymptomatic reversible pulpitis
  • Chronic hyperplastic pulpitis
  • Chronic pulpitis
  • Chronic ulcerative pulpitis
  • Pulpal abscess
  • Pulpitis
  • Reversible pulpitis
  • Suppurative inflammation of oral soft tissue
  • Suppurative pulpitis
  • Symptomatic reversible pulpitis

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

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

Clinical InformationClinical

  • Pulpitis

    inflammation of the dental pulp, usually due to bacterial infection in dental caries, tooth fracture, or other conditions causing exposure of the pulp to bacterial invasion. chemical irritants, thermal factors, hyperemic changes, and other factors may also cause pulpitis.

  • Dental Pulp

    a richly vascularized and innervated connective tissue of mesodermal origin, contained in the central cavity of a tooth and delimited by the dentin, and having formative, nutritive, sensory, and protective functions. (jablonski, dictionary of dentistry, 1992)

  • Pulpitis

    inflammation of the dental pulp.

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 K04.01 to ICD-9-CMHistory

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

ICD-9-CM
522.0 Pulpitis
Approximate The match is approximate rather than exact.

Code History & ChangesHistory

Replacement K04.01 replaces the following previously assigned code(s):

  • K04.0 - Pulpitis
FY 2019AddedAdded to the ICD-10-CM code setEffective October 1, 2018.
FY 2020–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About K04.01Overview

What is the ICD-10 code for reversible pulpitis?

The ICD-10-CM code for reversible pulpitis is K04.01 (sometimes written as K0401). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is K04.01 (Pulpitis) a billable code?

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

What MS-DRG does K04.01 group to?

When reversible pulpitis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 11, 12, 13, 157, 158, 159, with relative weights from 0.7085 to 5.4541 depending on complications. Higher weights mean higher Medicare reimbursement.

Is K04.01 a CC or MCC?

CMS lists K04.01 as a CC (complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 229 closely related codes in its exclusion list.

What is the ICD-9 equivalent of K04.01?

Under the General Equivalence Mappings, reversible pulpitis converts to ICD-9-CM 522.0 (pulpitis). The mapping is approximate, so confirm the match fits the documentation.