Measurement of anterior translation of the mandibular condyle using sonography.
Kai-Yu Ho, Brooke Laskowski, Danielle Garcia and 2 others
PMID 30774218WHAT IT FOUND
In 28 adults without jaw dysfunction, ultrasound reliably tracked how far the jaw joint slides forward during mouth opening.
The slide distance rose with mouth opening, but the study did not test people with jaw problems.
Key findings
01Ultrasound-based measurement showed high agreement between examiners and within examiners.
02Re-scanning 6 participants on another day also showed high agreement.
03The paper reported a positive relationship between mouth opening range of motion and forward jaw joint translation.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study measured adults without temporomandibular dysfunction and excluded mouth opening less than 35 mm, so it does not show what happens in painful or restricted jaws. Only 6 participants were rescanned to test image acquisition reliability, and they were chosen for availability. The method was not validated against MRI or CT, so accuracy of the measured translation is not established. The regression describes an association between mouth opening and translation; it does not show that one causes the other. The paper reports reliability and correlation only, not whether any treatment changed function.
Declared interests
The study was supported by the University of Nevada, Las Vegas Graduate & Professional Student Association Grant and the University of Nevada, Las Vegas Physical Therapy Student Opportunity Research Grant. The authors report no declarations of interest.
The easy way to misread this
Do not read this as evidence that ultrasound measurement or manual jaw mobilization improves temporomandibular dysfunction. The study tested healthy adults, did not validate the ultrasound method against MRI or CT, and did not test treatment.