Trismus (Limited Jaw Opening)

DC 9905Dental/Oral38 CFR 4.150, DC 9905

A condition where your jaw muscles tighten and you cannot open your mouth fully. It can be caused by surgery, radiation, trauma, or infection. The VA rates trismus based on how far you can open your mouth, measured in millimeters between your upper and lower front teeth (inter-incisal range).

How the VA rates this condition

The VA rates this condition based on objective clinical measurements and test results. The examiner will use standardized tests or lab values to determine the severity of your condition rather than relying primarily on subjective symptom reports.

Diagnostic code

DC 9905

Rating range

0% – 40%

Rating levels

Rating criteria are defined in 38 CFR 4.150, DC 9905. This guide presents a plain-language summary and is not a substitute for the full regulatory text. Always consult a VSO or VA-accredited attorney for case-specific advice.

Rating Levels

Your jaw opening is severely limited (10mm or less inter-incisal range). You can barely open your mouth, require a liquid or blended diet, and cannot eat normally.

What the VA looks for

Inter-incisal range 0-10mm measured at examination
Near-inability to open mouth
Liquid or blended diet required for nutrition
Speech impairment from limited jaw opening
Unable to perform dental hygiene adequately

Common Pitfalls

⚠Not having the inter-incisal range measured in exact millimeters — the rating is based on specific millimeter thresholds, so an estimate or description like "limited opening" is not sufficient for the VA.
⚠Not connecting trismus to the service-related cause — radiation for head/neck cancer treated during or after service, jaw fractures during service, or complications from military dental procedures all establish service connection.
⚠Not documenting the functional impact on eating and nutrition — keep a food diary showing what you can and cannot eat, any weight loss, and nutritional supplements needed.
⚠Not filing for secondary conditions — trismus can cause malnutrition, dental hygiene problems leading to tooth decay, speech difficulties, and depression from social eating limitations.
⚠Not requesting physical therapy records showing jaw mobilization exercises and their results — this documents ongoing treatment and can show whether the condition is improving or worsening.

Related DBQ Forms

DBQ Dental and Oral Conditions

View evidence checklist →See secondary conditions →

Condition Rating Guides

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Trismus (Limited Jaw Opening)

How the VA rates this condition

Diagnostic code

DC 9905

Rating range

0% – 40%

Rating levels

Rating Levels

Your jaw opening is severely limited (10mm or less inter-incisal range). You can barely open your mouth, require a liquid or blended diet, and cannot eat normally.

What the VA looks for

Inter-incisal range 0-10mm measured at examination
Near-inability to open mouth
Liquid or blended diet required for nutrition
Speech impairment from limited jaw opening
Unable to perform dental hygiene adequately

Common Pitfalls

⚠Not having the inter-incisal range measured in exact millimeters — the rating is based on specific millimeter thresholds, so an estimate or description like "limited opening" is not sufficient for the VA.

⚠Not connecting trismus to the service-related cause — radiation for head/neck cancer treated during or after service, jaw fractures during service, or complications from military dental procedures all establish service connection.

⚠Not documenting the functional impact on eating and nutrition — keep a food diary showing what you can and cannot eat, any weight loss, and nutritional supplements needed.

⚠Not filing for secondary conditions — trismus can cause malnutrition, dental hygiene problems leading to tooth decay, speech difficulties, and depression from social eating limitations.

⚠Not requesting physical therapy records showing jaw mobilization exercises and their results — this documents ongoing treatment and can show whether the condition is improving or worsening.