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Reversible Effects of Functional Mandibular Lateral Shift on Masticatory Muscles in Growing Rats

In this study, we aimed to determine the effects of functional mandibular lateral shift (FMLS) on the muscle mass, fiber size, myosin heavy chain fiber type, and related gene expression in masticatory muscles (masseter and temporalis), as well as whether the baseline levels could be recovered after...

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Detalles Bibliográficos
Autores principales: Guan, Hao, Yonemitsu, Ikuo, Ikeda, Yuhei, Ono, Takashi
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10452155/
https://www.ncbi.nlm.nih.gov/pubmed/37626623
http://dx.doi.org/10.3390/biomedicines11082126
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author Guan, Hao
Yonemitsu, Ikuo
Ikeda, Yuhei
Ono, Takashi
author_facet Guan, Hao
Yonemitsu, Ikuo
Ikeda, Yuhei
Ono, Takashi
author_sort Guan, Hao
collection PubMed
description In this study, we aimed to determine the effects of functional mandibular lateral shift (FMLS) on the muscle mass, fiber size, myosin heavy chain fiber type, and related gene expression in masticatory muscles (masseter and temporalis), as well as whether the baseline levels could be recovered after FMLS correction in growing rats. The FMLS appliance was placed to shift the mandible leftward by approximately 2 mm. After FMLS placement for 2 and 4 weeks, the muscles on the left side had significantly lower wet weight, mean cross-sectional area, and proportion of type IIa fibers than those on the right side or in the control groups (p < 0.05), with downregulation and upregulation of IGF-1 and GDF-8 gene expression, respectively (p < 0.05). Following 2 weeks devoted to recovery from FMLS, the muscle parameters in the recovery group were not significantly different to those of the control group, and IGF-1 expression in the left-side muscles was enhanced and GDF-8 expression was simultaneously suppressed. These findings indicate that the masticatory muscle changes induced via FMLS tend to revert to normal conditions if the intervention is eliminated at an early stage. Therefore, appropriate orthodontic treatment for FMLS during the growth period is advisable to prevent asymmetric alterations in masticatory muscles.
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spelling pubmed-104521552023-08-26 Reversible Effects of Functional Mandibular Lateral Shift on Masticatory Muscles in Growing Rats Guan, Hao Yonemitsu, Ikuo Ikeda, Yuhei Ono, Takashi Biomedicines Article In this study, we aimed to determine the effects of functional mandibular lateral shift (FMLS) on the muscle mass, fiber size, myosin heavy chain fiber type, and related gene expression in masticatory muscles (masseter and temporalis), as well as whether the baseline levels could be recovered after FMLS correction in growing rats. The FMLS appliance was placed to shift the mandible leftward by approximately 2 mm. After FMLS placement for 2 and 4 weeks, the muscles on the left side had significantly lower wet weight, mean cross-sectional area, and proportion of type IIa fibers than those on the right side or in the control groups (p < 0.05), with downregulation and upregulation of IGF-1 and GDF-8 gene expression, respectively (p < 0.05). Following 2 weeks devoted to recovery from FMLS, the muscle parameters in the recovery group were not significantly different to those of the control group, and IGF-1 expression in the left-side muscles was enhanced and GDF-8 expression was simultaneously suppressed. These findings indicate that the masticatory muscle changes induced via FMLS tend to revert to normal conditions if the intervention is eliminated at an early stage. Therefore, appropriate orthodontic treatment for FMLS during the growth period is advisable to prevent asymmetric alterations in masticatory muscles. MDPI 2023-07-27 /pmc/articles/PMC10452155/ /pubmed/37626623 http://dx.doi.org/10.3390/biomedicines11082126 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Guan, Hao
Yonemitsu, Ikuo
Ikeda, Yuhei
Ono, Takashi
Reversible Effects of Functional Mandibular Lateral Shift on Masticatory Muscles in Growing Rats
title Reversible Effects of Functional Mandibular Lateral Shift on Masticatory Muscles in Growing Rats
title_full Reversible Effects of Functional Mandibular Lateral Shift on Masticatory Muscles in Growing Rats
title_fullStr Reversible Effects of Functional Mandibular Lateral Shift on Masticatory Muscles in Growing Rats
title_full_unstemmed Reversible Effects of Functional Mandibular Lateral Shift on Masticatory Muscles in Growing Rats
title_short Reversible Effects of Functional Mandibular Lateral Shift on Masticatory Muscles in Growing Rats
title_sort reversible effects of functional mandibular lateral shift on masticatory muscles in growing rats
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10452155/
https://www.ncbi.nlm.nih.gov/pubmed/37626623
http://dx.doi.org/10.3390/biomedicines11082126
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