Effect of isometric exercises on the masseter muscle in older adults with missing dentition: a randomized controlled trial

Satoru Takano,Kazuharu Nakagawa,Kohei Yamaguchi,Kanako Yoshimi,Ayako Nakane,Haruka Tohara,Takuma Okumura

doi:10.1038/s41598-021-86807-w

Satoru Takano, Kazuharu Nakagawa + Show 5 more

Open Access

https://doi.org/10.1038/s41598-021-86807-w

Copy DOI

Abstract

Maintaining oral function in older individuals with missing teeth is important for leading a healthy and independent life. This study aimed to evaluate whether simple isometric exercises can maintain and improve the oral function [maximum occlusal force (MOF) and masticatory ability (MA)] and the masticatory muscle properties [masseter muscle thickness (MMT) and echo intensity (MMEI)] in older adults during the maintenance phase of removable prosthetic treatment. Participants were randomly categorized into the intervention and control groups. The mouthpieces were distributed, and participants were instructed to use them for exercising. The intervention group was instructed to perform maximum clenching for 10 s, whereas the control group was instructed to tap the teeth at an arbitrary speed for 10 s. Both were repeated five times at an interval of 5 s between each activity and twice daily for 4 weeks. The outcomes were measured after a month of exercise. The intervention group showed a significant improvement in the MOF, MMT during contraction, MMT at rest and MMEI during contraction. There were no significant differences in the MA and MMEI at rest. In the control group, no improvement was observed in any of the parameters. When the isometric exercises were performed using a mouthpiece, there was an improvement in the oral function and masseter muscle properties in older individuals with Eichner B status who used dentures.

Highlights

Background and objectiveA decrease in the oral function, represented by the maximum occlusal force (MOF) and the masticatory ability (MA), is a risk factor for adverse events such as sarcopenia and death[1]
MOF and MA greatly influence dietary choices[2]; a reduced bite force quotient leads to protein, fiber, mineral, and vitamin deficiencies[3,4,5], resulting in a risk of u ndernutrition[6]
Aging and tooth loss are mainly considered to be responsible for a decrease in the MA and M OF7; these are reportedly related to the properties of masticatory muscles, especially of the masseter

Summary

Introduction

Background and objectiveA decrease in the oral function, represented by the maximum occlusal force (MOF) and the masticatory ability (MA), is a risk factor for adverse events such as sarcopenia and death[1]. Masseter muscle thickness (MMT) is reportedly associated with MOF8, and masseter muscle echo intensity (MMEI) is negatively correlated with MOF and M MT9. Several previous studies have reported that the MA, MOF, and MMT are greatly improved with dental prosthetic treatments such as implants and d entures[11,12,13]. In addition to prosthetic treatment, isometric exercise is used as a modality for maintaining oral function. A retrospective comparative study of 28 young people showed that a simple isometric exercise using a mouthpiece resulted in an improvement in the M OF14. The purpose of this study was to clarify whether simple isometric exercises can maintain and improve the oral function (MOF and MA) and masticatory muscle properties (MMT and MMEI) in older adults during the maintenance phase of removable prosthetic treatment

Objectives

Methods

Results

Conclusion