2026 ICD-10-CM Diagnosis Code M26.221Open posterior occlusal relationship
ICD-10-CM Codes›M00–M99›M26-M27›M26
- Billable — Valid for Submission
- Not Chronic
M26.221 is a billable ICD-10-CM diagnosis code for open posterior occlusal relationship. 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 left posterior open bite. 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
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Left posterior open bite
- Open bite
- Posterior open bite
- Right posterior open bite
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Posterior open bite
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
Index to Diseases and InjuriesGuidance
External Cause of Injuries IndexGuidance
References for this code in the External Cause of Injuries Index.
- Open, opening
- bite
- posterior
- Relationship
- occlusal
- open posterior
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Open Bite
a condition in which certain opposing teeth fail to establish occlusal contact when the jaws are closed.
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 M26.221 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About M26.221Overview
Is M26.221 (Open occlusal relationship) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report open posterior occlusal relationship on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does M26.221 group to?
When open posterior occlusal relationship 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 M26.221?
Under the General Equivalence Mappings, open posterior occlusal relationship converts to ICD-9-CM 524.25 (open posterior occlusion). 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.
