2026 ICD-10-CM Diagnosis Code M26.4Malocclusion, unspecified

ICD-10-CM Codes›M00–M99›M26-M27›M26

ICD-10-CM M26.4
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M26.4 is a billable ICD-10-CM diagnosis code for malocclusion, 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. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Any dental condition including traumatic injury, Disorders of jaw, and Disorders of teeth and gingiva.

Code Identity

ICD-10-CM Code
M26.4
Billable Status
Yes — Valid for Submission
Code Describes
Malocclusion, unspecified
Short Description
Malocclusion, unspecified
Same as the full description in the CMS dataset.
Parent Code
M26
Dentofacial anomalies [including malocclusion]

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM26-M27Dentofacial anomalies [including malocclusion] and other disorders of jaw
CategoryM26Dentofacial anomalies [including malocclusion]
This CodeM26.4Malocclusion, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Dental fremitus
  • Disto-occlusion of teeth
  • Hyperocclusion
  • Hyperplasia of gingiva
  • Injury of periodontal tissue
  • Localized secondary occlusal trauma
  • Malocclusion due to abnormal frenum attachment
  • Malocclusion due to gingival hyperplasia
  • Malocclusion due to intraoral soft tissue chewing
  • Malocclusion due to lip habit
  • Malocclusion due to object habits
  • Malocclusion of teeth
  • Minimally compromised occlusal scheme
  • Moderately compromised dentate occlusal scheme
  • Moderately compromised occlusal scheme
  • Moderately compromised partially dentate occlusal scheme
  • Occlusal trauma
  • Open bite
  • Overeruption of tooth
  • Protrusion of tooth
  • Secondary occlusal trauma
  • Severely compromised dentate occlusal scheme
  • Severely compromised occlusal scheme
  • Severely compromised partially dentate occlusal scheme
  • Skeletal malocclusion
  • Substantially compromised dentate occlusal scheme
  • Substantially compromised occlusal scheme
  • Substantially compromised partially dentate occlusal scheme
  • Supereruption of tooth associated with malocclusion

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.

    • Anomaly, anomalous(congenital) (unspecified type)
      • dentofacial
        • malocclusion
    • Malocclusion(teeth)

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 MUS029
Disorders of jaw
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR DIG002
Disorders of teeth and gingiva
Default principal diagnosis: inpatient No · outpatient No
CCSR DEN002
Nontraumatic dental conditions
Default principal diagnosis: inpatient No · outpatient No

Clinical InformationClinical

  • Malocclusion

    such malposition and contact of the maxillary and mandibular teeth as to interfere with the highest efficiency during the excursive movements of the jaw that are essential for mastication. (jablonski, illustrated dictionary of dentistry, 1982)

  • Malocclusion, Angle Class I

    malocclusion in which the mandible and maxilla are anteroposteriorly normal as reflected by the relationship of the first permanent molar (i.e., in neutroclusion), but in which individual teeth are abnormally related to each other.

  • Malocclusion, Angle Class II

    malocclusion in which the mandible is posterior to the maxilla as reflected by the relationship of the first permanent molar (distoclusion).

  • Malocclusion, Angle Class III

    malocclusion in which the mandible is anterior to the maxilla as reflected by the first relationship of the first permanent molar (mesioclusion).

  • Open Bite

    a condition in which certain opposing teeth fail to establish occlusal contact when the jaws are closed.

  • Malocclusion

    an inherited or acquired dental abnormality characterized by improper alignment of the teeth.

  • Hyperocclusion

    contact of a tooth or restoration such that it encrouches on the interocclusal freeway space.

Patient EducationClinical

Jaw Injuries and Disorders

Your jaw is a set of bones that holds your teeth. It includes:

Read the full article at MedlinePlus

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

Convert M26.4 to ICD-9-CMHistory

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

ICD-9-CM
524.4 Malocclusion NOS
Approximate The match is approximate rather than exact.

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 M26.4Overview

Is M26.4 (Dentofacial anomalies [including malocclusion]) a billable code?

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

What MS-DRG does M26.4 group to?

When malocclusion, 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 M26.4?

Under the General Equivalence Mappings, malocclusion, unspecified converts to ICD-9-CM 524.4 (malocclusion NOS). 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.