Effects of chewing exercises on the occlusal force and masseter muscle thickness in community‐dwelling Koreans aged 65 years and older: A randomised assessor‐blind trial

Abstract

Chewing exercises have been applied in clinical settings to improve the occlusal force and function of the masseter muscle in elderly individuals. However, the clinical relevance and effects of chewing exercises are unclear. This study aimed to investigate the effects of bilateral chewing exercises on the occlusal force and masseter muscle thickness in community‐dwelling Koreans aged 65 years. Forty community‐dwelling healthy elderly individuals were enrolled in this study. They were assigned to the experimental or the control group. The experimental group performed chewing exercises using medical equipment developed to facilitate such exercises. The chewing exercises were divided into isometric and isotonic types and were performed for 20 min/d, 5 days/wk, for 6 weeks. The control group did not perform any chewing exercises. The outcome measures were occlusal force and masseter muscle thickness, which were evaluated using an occlusometer and ultrasound device, respectively. A paired t test and an independent t test were used to evaluate the training effects. Within‐group comparisons showed that occlusal force and masseter muscle thickness improved significantly in the experimental group (P < .001 for both), while the control group showed no significant improvements (P = .098 and .130). Between‐group comparisons showed that the experimental group had a greater increase in occlusal force and masseter muscle thickness (P < .05 for both) compared to the control group. These results suggest that chewing exercises are effective in improving occlusal force and masseter muscle thickness in healthy elderly individuals.

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

“…Furthermore, it has been reported that chewing exercises for older people with 24 or more remaining teeth improved MOF [27]. In this study, we targeted older adults with missing teeth and found an improvement in MOF, which was consistent with previous studies [14,27].…”

Interrelationships among whole-body skeletal muscle mass, masseter muscle mass, oral function, and dentition status in older Japanese adults

“…Previous studies have demonstrated that the loss of muscle mass is associated with the loss of strength [ 30 ] and functional impairment [ 14 ] in older adults. Another study demonstrated that masseter muscle thickness and occlusal force can simultaneously improve with chewing exercise [ 31 ]. Considering the above findings, it is biologically plausible that SMM has direct effects on e-MMM and that e-MMM has direct effects on masseter muscle strength and function, as shown in our study.…”

A Systematic Review and Meta-analysis of the Effect of Oral Exercises on Masticatory Function

“…Another possible reason is that bite force is a direct reflection of the masticatory muscle strength, while mastication depends on many factors other than muscle strength. It is believed that resistance training, like chewing or clenching exercise, can provoke a myophysiological response of masseter muscle fibers, which leads to increased muscle strength and thickness (Kim et al 2020; Park et al 2020). Nevertheless, mastication is a complicated process requiring the coordinated movements of the lips, jaw, tongue, cheek, soft palate, and the masticatory muscles, which can also be affected by other factors such as the dentition status and gustatory sense.…”

“…Characteristics of the included studies are shown in Table 1. They were published in English (17/18) and Japanese (1/18) and were conducted in 7 countries, namely, Japan (Kawamura and Horio 1989;Ibayashi et al 2008;Sugiyama et al 2013;Ohara et al 2015;Nakagawa et al 2017;Shirai et al 2018;Matsubara et al 2021;Matsuo et al 2021), South Korea (Cho et al 2012;Kim et al 2019Kim et al , 2020Kim et al , 2021Park et al 2020), United States (Yurkstas 1953;Thompson et al 2001), Sweden (Tzakis et al 1989;Kiliaridis et al 1995;He et al 2013), Greece (Tzakis et al 1989;Kiliaridis et al 1995), China (Liu et al 2017), and Denmark (Baram et al 2020). Among the included studies, 12 studies were conducted on elders (≥65 y), and most of them were community-dwelling elders; 6 studies involved young adults (19-35 y) who were mainly university students and staff.…”