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In Vivo Functional Assessment of Rat Masseter Muscle Following Surgical Creation of a Volumetric Muscle Loss (VML) Injury
Published on: November 15, 2024
Masseter myosin heavy chain composition varies with mandibular asymmetry
Gwénaël Raoul1, Anthea Rowlerson, James Sciote
1Université Lille Nord de France, UDSL, Lille, France. gwenael.raoul@gmail.com
The Journal of Craniofacial Surgery
|May 19, 2011
Summary
Mandibular asymmetry in patients undergoing orthognathic surgery is linked to specific masseter muscle fiber changes. This finding may influence future jaw discrepancy treatments and understanding of the condition's causes.
Area of Science:
- Orthodontics and Oral Surgery
- Skeletal Muscle Physiology
- Craniofacial Anatomy
Background:
- Jaw dysmorphologies, including malocclusion and inappropriate jaw relationships, are common in young patients.
- Mandibular asymmetry is a frequent dysmorphology, but its underlying causes are often unknown.
- Orthognathic surgery is a common treatment for severe malocclusion and jaw discrepancies.
Purpose of the Study:
- To investigate if masseter muscle phenotype composition differs between the right and left sides in patients with mandibular asymmetry.
- To compare masseter muscle composition in patients with and without mandibular asymmetry undergoing orthognathic surgery.
- To explore the potential role of masseter muscle phenotype in the etiology of mandibular asymmetry.
Main Methods:
- Cephalometric analysis was performed on 50 patients undergoing orthognathic surgery.
- Masseter muscle samples were obtained from both sides of the jaw for each patient.
- Immunostaining with myosin-isoform-specific antibodies identified four skeletal muscle fiber types; fiber areas and proportions were measured.
Main Results:
- Patients with mandibular asymmetry showed a significant increase in type II fiber occupancy on the side of the deviation (P = 0.0035).
- No significant differences in masseter muscle fiber composition were observed between sides in patients without mandibular asymmetry.
- Fiber areas and proportions varied significantly between sides in the mandibular asymmetry group.
Conclusions:
- Masseter muscle phenotype composition is significantly associated with mandibular asymmetry.
- These findings have implications for the physiotherapeutic and surgical management of jaw discrepancies.
- Further research is warranted to elucidate the role of masseter muscle phenotype in the etiology of mandibular asymmetry.
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