2026 ICD-10-CM Diagnosis Code M26.57Lack of posterior occlusal support

ICD-10-CM Codes›M00–M99›M26-M27›M26

ICD-10-CM M26.57
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M26.57 is a billable ICD-10-CM diagnosis code for lack of posterior occlusal support. 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. Coders also document this condition as functional occlusion. 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
M26.57
Billable Status
Yes — Valid for Submission
Code Describes
Lack of posterior occlusal support
Short Description
Lack of posterior occlusal support
Same as the full description in the CMS dataset.
Parent Code
M26.5
Dentofacial functional abnormalities

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 CodeM26.57Lack of posterior occlusal support

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Functional occlusion
  • Lack of posterior occlusal support

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 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

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 M26.57 to ICD-9-CMHistory

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

ICD-9-CM
524.57 Lack post occlsl support
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 M26.57Overview

What is the ICD-10 code for lack of posterior occlusal support?

The ICD-10-CM code for lack of posterior occlusal support is M26.57 (sometimes written as M2657). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is M26.57 (Dentofacial functional abnormalities) a billable code?

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

What MS-DRG does M26.57 group to?

When lack of posterior occlusal support 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.

What is the ICD-9 equivalent of M26.57?

Under the General Equivalence Mappings, lack of posterior occlusal support converts to ICD-9-CM 524.57 (lack post occlsl support). The mapping is a direct match.