80-90% of patients with radiation to the pterygoid and/or masseter muscles will develop trismus.

Trismus 35mm MIO and Three Finger Technique

What is trismus? What causes trismus?

Trismus is defined as any restriction to mouth opening. Radiation treatment for head and neck cancer, surgery, trauma and TMJ disorders may all lead to the development of trismus.

How do you diagnose trismus?

The average adult maximal interincisal opening (MIO) is 50mm. Clinical diagnosis of trismus is a MIO of 35mm or less. Using the 3-finger diagnostic (see above picture) it is indicated at 2-fingers or less.

Trismus complications include:

  • Oral Pain & Joint Dysfunction

  • Disruption of oral hygiene and dental treatments
  • Difficulty speaking & eating
  • Compromised denture and prosthetic insertion & removal
  • Compromised airway access

How can you prevent and treat trismus? 

Exercise therapy decreases both the incidence and severity of trismus. Jaw motion rehab systems like the OraStretch® press are most efficacious. 


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The OraStretch® Press Jaw Motion Rehab System

For the prevention & treatment of trismus & joint dysfunction

The OraStretch press Jaw motion rehab system

-    Includes confirmation of insurance eligibility & billing. 

-    Free shipping, size exchanges and 5-year limited warranty.

-    OraStretch press power bands offer dynamic stretching & active resistance therapy  

OraStretch press with no wings or one sided

For patients unable to use standard bite plates, we provide adjusted bite plates for a better fit.  By removing both wings or one side of the mouthpiece, we are better able to meet your patients' needs.


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Michelle Yates

Date 2/25/2022

I am a speech-language pathologist specializing in treating Patients with head and neck cancer. I work in a robust outpatient clinic with 10-11 SLPs and PTs (1-2). We treat trismus and TMJ and are interested in an inservice on your products. Please contact me.

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