Symmetrical activity of the chewing muscles and its relationship with skeletal class and body posture

ABSTRACT

Objective

To describe the role of body posture and skeletal class in the symmetrical activity of chewing muscles.

Methods

Descriptive study with association. Skeletal class measured by the Steiner method. Postural analysis through APECS mobile application for forward head posture and shoulder discrepancy, and surface electromyography with Biopac® device.

Results

The skeletal class, forward head posture, and shoulder discrepancy presented statistical association with the symmetrical electromyographic response of digastric muscles and masseter muscles during swallowing.

Discussion

This study exhibited a positive relationship between digastric muscle symmetry and skeletal class during swallowing. The compensation of the hyoid system explains these results, showing that skeletal Class III has better electromyographic balance. In contrast, masseter muscle symmetry during swallowing presented a negative relationship with skeletal class. The stabilization role that this muscle plays during swallowing explains these findings, caused by the different lengths and direction of this muscle in skeletal Class III.

KEYWORDS:

• Electromyography
• posture
• jaw abnormalities
• hyoid bone

Acknowledgments

The authors want to thank Dr. Mariano Rocabado Seaton for loaning the electromyographic device.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors state that there is no external funding.