Related Experiment Video
Updated: Jan 4, 2026

In Vivo Functional Assessment of Rat Masseter Muscle Following Surgical Creation of a Volumetric Muscle Loss (VML) Injury
Published on: November 15, 2024
Do subjects with forced lip closure have different perioral and jaw muscles activity?
Natalia Andrea Gamboa1,2, Aler Daniel Fuentes1,2, Carolina Paz Matus1
1Faculty of Dentistry, Institute for Research in Dental Sciences, University of Chile, Santiago, Chile.
Abstract:
Objective: To evaluate the activity of mentalis (MN), buccinator (BC), and suprahyoid (SH) muscles among participants with different lip competence..Methods: Sixty-three participants were classified clinically and assigned to the following groups of 21 each: 1) competent lips (competent), 2) incompetent lips (incompetent), or 3) forced lip closure (forced). Activity was recorded at rest, swallowing, speaking, reciprocal compression of the lips, and chewing.Results: MN activity in incompetent was significantly higher than competent at rest, and it was significantly higher in incompetent and forced when compared with competent during swallowing (p< .05). No differences among incompetent and forced were observed (p> .05). During speaking, reciprocal compression of the lips, and chewing, MN activity did not show significant differences among groups. BC and SH activity did not show significant differences (p> .05).Conclusion: MN activity during swallowing can be considered a relevant biomarker to differentiate between forced and competent participants.
Related Concept Videos
Muscles for Facial Expressions
Assessment of Airway, Skin Color, and Use of Accessory Muscles
Introduction
The initial evaluation of a patient's respiratory system...
Facial Feedback Hypothesis
Assessment of the Mouth
Mouth Inspection
The inspection begins with visually examining the mouth for symmetry, color, and size.
Deglutition
Swallowing can be divided into three stages: the voluntary phase, the pharyngeal phase, and the esophageal phase. Although the...
Mechanism of Breathing III: The Accessory Muscles
The respiratory system is a complex network that relies on primary respiratory muscles like the diaphragm, but also involves accessory muscles to enhance lung expansion and airflow during both inhalation and exhalation.
Enhancing Inhalation with Accessory Muscles:
Accessory muscles such as the sternocleidomastoid, scalene, intercostal, and abdominal muscles are crucial when additional respiratory effort is required, such as during deep...

