Quantitative and qualitative evaluation of the masseter muscle by ultrasonography and correlation with whole body health status.
Rika Kobayashi, Shugo Haga, Akito Umehara and 3 others
PMID 38434992WHAT IT FOUND
In 30 young dentists, ultrasound-measured masseter thickness correlated with BMI, weight, handgrip strength, and tongue pressure.
However, masseter elasticity did not change with contraction, and brightness correlated with body fat but not muscle strength. These links are correlational and do not prove ultrasound measures whole-body health.
Key findings
01Masseter muscle thickness at rest and during contraction was positively correlated with body weight, BMI, handgrip strength, and tongue pressure.
02The hypothesis that masseter elasticity would increase during contraction was not supported; no significant correlation was found.
03Masseter muscle brightness correlated positively with BMI and body fat, but not with bite force or handgrip strength.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The sample was very small (n=30) and consisted entirely of young, healthy dentists, limiting generalizability to older adults or patients with pathology. The study was cross-sectional, so it cannot determine causality between masseter changes and whole-body health. The narrow age range (mean 28.0 ± 2.3 years) prevented analysis of age-related muscle changes. Ultrasound elasticity measures were affected by participant fatigue and probe movement, and the expected change during contraction was not observed.
Declared interests
The work was supported by JSPS KAKENHI (grant number 23K09422). The authors declared no conflicts of interest.
The easy way to misread this
Do not interpret the correlation between masseter thickness and handgrip strength as evidence that ultrasound can diagnose systemic muscle weakness or sarcopenia. This finding comes from 30 young, healthy dentists and may not apply to patients with disease or advanced age.