2026 ICD-10-CM Diagnosis Code K02.51Dental caries on pit and fissure surface limited to enamel

ICD-10-CM Codes›K00–K95›K00-K14›K02

ICD-10-CM K02.51
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K02.51 is a billable ICD-10-CM diagnosis code for dental caries on pit and fissure surface limited to enamel. 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; Caries, periodontitis, and other preventable dental conditions; and Disorders of teeth and gingiva.

Code Identity

ICD-10-CM Code
K02.51
Billable Status
Yes — Valid for Submission
Code Describes
Dental caries on pit and fissure surface limited to enamel
Short Description
Dental caries on pit and fissure surface limited to enamel
Same as the full description in the CMS dataset.
Parent Code
K02.5
Dental caries on pit and fissure surface

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK00-K14Diseases of oral cavity and salivary glands
CategoryK02Dental caries
This CodeK02.51Dental caries on pit and fissure surface limited to enamel

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Dental caries on pit and fissure surface limited to enamel
  • Pit and fissure caries
  • Primary dental caries, pit and fissure origin

Tabular List NotesGuidance

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

Inclusion Terms

  • White spot lesions initial caries on pit and fissure surface 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.

    • Caries
      • dental (dentino enamel junction) (early childhood) (of dentine) (pre-eruptive) (recurrent) (to the pulp)
        • chewing surface
          • limited to enamel
    • Caries
      • dental (dentino enamel junction) (early childhood) (of dentine) (pre-eruptive) (recurrent) (to the pulp)
        • coronal surface
          • chewing surface
            • limited to enamel
    • Caries
      • dental (dentino enamel junction) (early childhood) (of dentine) (pre-eruptive) (recurrent) (to the pulp)
        • coronal surface
          • pit and fissure surface
            • limited to enamel
    • Caries
      • dental (dentino enamel junction) (early childhood) (of dentine) (pre-eruptive) (recurrent) (to the pulp)
        • pit and fissure surface
          • limited to enamel
    • Caries
      • initial (tooth)
        • chewing surface
    • Caries
      • initial (tooth)
        • pit and fissure surface
    • Lesion(s) (nontraumatic)
      • tooth, teeth
        • white spot
          • chewing surface
    • Lesion(s) (nontraumatic)
      • tooth, teeth
        • white spot
          • pit and fissure surface
    • Lesion(s) (nontraumatic)
      • white spot (tooth)
        • chewing surface
    • Lesion(s) (nontraumatic)
      • white spot (tooth)
        • pit and fissure surface
    • White
      • spot lesions, teeth
        • chewing surface
    • White
      • spot lesions, teeth
        • pit and fissure surface

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 Decay

Tooth decay is damage to a tooth's surface, or enamel. It happens when bacteria in your mouth make acids that attack the enamel. Tooth decay can lead to cavities (dental caries), which are holes in your teeth. If tooth decay is not treated, it can cause pain, infection, and even tooth loss.

The full article covers:

  • What is tooth decay?
  • What causes tooth decay?
  • Who is at risk for tooth decay?
  • What are the symptoms of tooth decay and cavities?
  • How are tooth decay and cavities diagnosed?
  • What are the treatments for tooth decay and cavities?
  • Can tooth decay be prevented?

Read the full article at MedlinePlus

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

Convert K02.51 to ICD-9-CMHistory

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

ICD-9-CM
521.06 Dentl caries-pit/fissure
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.
ICD-9-CM
521.01 Dental caries - enamel
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.

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 K02.51Overview

Is K02.51 (Dental caries on pit and fissure surface) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report dental caries on pit and fissure surface limited to enamel on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does K02.51 group to?

When dental caries on pit and fissure surface limited to enamel 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 K02.51?

Under the General Equivalence Mappings, dental caries on pit and fissure surface limited to enamel converts to ICD-9-CM 521.06 (dentl caries-pit/fissure) and 521.01 (dental caries - enamel). The mapping is approximate, so confirm the match fits the documentation.

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.