Effectiveness of Resistance Training of Masticatory Muscles for Patients With Temporomandibular Disorders: A Systematic Review

Abstract

Background: Evidence supports the use of exercise for patients with temporomandibular disorders (TMDs). However, previous studies have mainly focused on combined treatment strategies or undefined exercise modalities.

Objective: This systematic review aims to evaluate the effectiveness of Resistance Training (RT) as a standalone treatment for managing pain and improving neuromuscular performance in individuals with TMDs.

Methods: This systematic review followed a pre-established and published protocol, which was registered with PROSPERO (CRD42023476269). The literature search was conducted from March 1st 2024 to March 31st 2024 via the following electronic databases: MEDLINE (OVID interface), EMBASE (OVID interface), SCOPUS, Web of Science, PubMed, and Cochrane Central Register of Controlled Trials (CENTRAL). Randomised controlled trials or nonrandomised studies of interventions were included when they compared the effect of RT targeting masticatory muscles on pain, neuromuscular performance, and maximum mouth opening in patients with TMDs versus other treatment modalities. Two independent reviewers screened articles for inclusion, extracted data, assessed the risk of bias using the revised Cochrane risk of bias tool for randomised trials and evaluated the overall quality of evidence using the Grading of Recommendations, Assessment, Development and Evaluations approach.

Results: From an initial 2177 articles, only three met the inclusion criteria and involved 108 participants. All the included studies demonstrated a decrease in pain intensity and an improvement in neuromuscular performance following RT, even if the superiority of RT over other interventions remains uncertain. However, the combination of moderate risk of bias, significant heterogeneity and small sample sizes resulted in a very low quality of evidence.

Conclusions: Clinicians managing patients with TMDs should consider RT as an effective, conservative option in conjunction with other treatment modalities. Future methodologically robust studies with large sample sizes and clearly defined exercise protocols are needed to investigate the role of RT for reducing TMD-related pain by increasing load tolerance and addressing potential bruxism-related muscle overload.

Keywords: exercise; masticatory muscle; pain; physical therapy; resistance training; temporomandibular disorder; temporomandibular joint.

FIGURE 1

PRISMA flow diagram which included searches of databases, registers and other sources [35].

FIGURE 2

Risk of bias 2 rating assessment for each study in all domains.

FIGURE 3

The effect of RT on pain intensity in the included studies, from baseline to follow‐up. (a) Giannakopoulos et al. (2018) reported a significant reduction in pain intensity measured by the characteristic pain intensity scale from baseline to the 12 week follow‐up. The RT protocol involved device‐supported sensorimotor training. (b) Barbosa et al. (2019) observed a significant reduction in temporal muscle pain upon palpation, measured using a VAS, from baseline to 8 weeks. The RT protocol employed biting endurance with visual biofeedback. (c) Gavish et al. (2006) noted a significant reduction in current pain intensity, measured using a VAS, from baseline to 8 weeks. The RT protocol involved progressive chewing exercises using sugarless gum.