Overview

Trismus, also known as "lockjaw”, is a condition characterised by a decrease in jaw mobility, which affects the ability of a person to eat, speak, or even clean the oral cavity. This has been seen following head and neck cancers, temporomandibular joint (TMJ) disorders, trauma, and sometimes dental procedures. Limited opening of the jaws leads to frustration, discomfort, and ultimately a reduced quality of life. However, patients with trismus can experience gradual improvement in their range of motion and overall functionality with targeted exercises designed to improve jaw mobility. This article describes effective jaw mobility exercises tailored to help trismus patients regain flexibility and reduce discomfort.

Precautions and guidelines

Consultation with healthcare professionals

Prior to the initiation of any exercise training, patients should consult with their healthcare team, including an oncologist, dentist, and physical therapist, in order to perform the exercise accordingly.¹

Early and structured intervention

Early institution of jaw exercises in a structured manner has been associated with better outcomes regarding mouth opening and quality of life.²

Consistency and adherence

Exercises prescribed by physicians should be done regularly. It has also been seen in various studies that regular exercise practice significantly improves mouth opening, alleviating symptoms of trismus.³

Avoid overexertion

The patient should execute the exercises mildly so as not to strain the muscles or injure them. Overexertion may lead to increased discomfort and may hinder progress.⁴

Monitoring progress

Regular measurement of mouth opening can help monitor progress and modify the exercise program if necessary. This must be done by a healthcare provider.⁵

Pain management

Mild pain can be experienced in some exercises; however, when the pain persists or is severe, it is essential to consult a healthcare provider to modify the exercise plan.⁶

Assistive devices

Jaw mobilising instruments may be suggested to assist with exercises. The use of such devices should always be under the guidance of a professional to ensure proper technique and avoid injury.⁷

These guidelines ensure maximum efficiency for treating trismus through jaw exercise therapy and assist in recovering some of their impaired functional capacity, besides enhancing patients' quality of life.

Jaw mobility exercises

Jaw mobility exercises are the backbone in the management of trismus condition, focusing on pain relief and improvement in the function of the jaws. The different types of exercises can be summarised into the following categories.

Cheek massage

This is done to loosen facial muscles, hence reducing stiffness and jaw pain.

Jaw stretching

Stretching is done with gradually increasing stretches made using instruments like tongue depressors or jaw stretching device.

Facial muscle movements

These are lip puckering and smiling exercises that aim to enhance overall facial mobility.

Tongue exercises

Tongue-moving around in all directions to increase its flexibility.

Chewing and sucking movements 

These are also practised so that the mastication muscles can be used.

Incorporating these exercises into a treatment regimen should be done under professional guidance to ensure proper technique for an individual's specific condition and to reduce the risk of potential complications.¹ Participants who followed this program reported considerable improvements in mouth opening and reduced discomfort over time.⁸

Mobility aids and tools

Jaw mobility aids and tools are highly important in the recovery of patients who have limited jaw movement, such as trismus, which is usually caused by head and neck cancer treatments. These devices help improve mouth opening and overall jaw function.

TheraBite® jaw motion recovery system™

The TheraBite® system is a handheld device that stretches the jaw muscles and joints to open the mouth wider. A randomised controlled trial was conducted to compare the effects of the TheraBite® with the Dynasplint Trismus System® in patients with head and neck cancer and trismus. The result was that the maximal mouth opening (MMO) increased by 3.0 mm in patients who used the TheraBite®, which showed its effectiveness in jaw recovery.⁹

Dynasplint trismus system® (DTS)

Another device included the DTS, which works to minimise jaw mobility by applying a low-load, prolonged-duration stretch to the jaw muscles. Patients utilising the DTS in the same study above had an increase of MMO by 1.5 mm. Although both devices lead to improvements, no significant differences were found between them, and thus, the choice may be dependent on patient-specific factors.⁹

Spring-bite device

The Spring-Bite device's design features, its possible applications and clinical use were reviewed in an article in the Journal of Cranio-Maxillofacial Surgery reporting a case. In a clinical evaluation study, its applicability is superior to prevent TMJ hypomobility, as a useful addition for postoperative.¹⁰

Jaw motion tracking systems

Advances in technology have led to the development of jaw motion tracking systems that allow for real-time monitoring and analysis of jaw movement. These can be used along with sensors and software to aid in detailed assessments of jaw functions, thus ensuring individualised treatment plans.¹¹

Among the literature available, several different methods and tools have been provided for the differential treatment of difficult mandibular disorders.¹¹ These devices should be introduced into a recovery program under the guidance of a healthcare professional so that they are used appropriately and to perform the specific treatment for the specific needs of the individual. The monitoring and adjustment may be done regularly to achieve the best possible outcome in jaw mobility and function.

Case studies

Several studies have been conducted to explore the use of exercise therapy in enhancing mobility. A prospective study on head and neck cancer patients assessed a 10-week structured jaw exercise program to enhance jaw mobility after radiotherapy. Patients in the intervention group performed daily exercises using devices such as the TheraBite® system or tongue depressors to stretch the jaw.²

Results

The intervention group showed a statistically significant increase in maximal interincisal opening (MIO) compared to the control group, in which the average increased from 27 mm to 40.1 mm, compared to the control group, which only reached 33.9 mm.

Long-term outcomes

Three years after the completion of the program, participants reported improved eating, speaking, and reduced jaw stiffness.²

A review published in Frontiers in Neurology suggests that coordination exercises like mouth-opening and mouth-closing isotonic movements (contraction in the absence of resistance) significantly improve the range of motion of the mandible (jaw or jawbone) and reduce pain in TMJ disorder patients.¹²

In another article in the Journal of Oral & Facial Pain and Headache, TMJ disorder experts reveal that exercises for the jaw are helpful for patients with jaw muscle myalgia, which is a limited opening of the mouth due to hyperactivity in the jaw-closing muscles.¹³

Monitoring progress

The frequency of exercise is regularly monitored in order to measure improvement and adjust the program.

Measurement of maximum interincisal opening (MIO)

Procedure

Take a ruler and measure the space between the upper and lower central incisors while the mouth is open as far as possible.

Frequency: weekly

A gain in MIO indicates increased jaw mobility.⁴

Symptom monitoring

Maintain a daily diary recording the pain, problems in eating, speaking difficulties, etc.

Purpose: Recognises patterns and evaluates exercises

Quality of life evaluation

Tool:

Questionnaires, for example, the Gothenburg Trismus Questionnaire to judge daily activity as well as quality of life

Frequency: To be done on a monthly basis

According to Acta Oncologica, the most crucial part is structured jaw exercise therapy to help the patients open the mouth wider, hence enhancing quality of life, after all, with trismus resulting from head and neck cancer.⁴

When to seek professional help

Seek medical attention if you have any of the following:

• Persistent or worsening symptoms 
• Symptoms do not improve or worsen with regular exercise
• Intense Pain. Feeling sharp pain during or after the workouts
• Inability to carry out daily activities because of limited jaw movement

Early intervention with structured jaw exercise therapy has been shown to result in increased mouth opening, a reduction in trismus-related symptoms, and improved health-related quality of life in patients suffering from head and neck cancer. It is recommended that therapy begin early and continue long-term.²

Summary

Trismus, or limited jaw motion, impacts the ability to eat, speak, or maintain oral hygiene. Recovery must include exercises that aim to improve jaw movement. Passive methods include using the tongue depressor to slowly move the jaw, whereas active exercises require opening, closing, and laterally moving the jaw. Controlling devices for stretching, such as TheraBite, can be used. Moreover, massages and warm compresses ease the muscles to be exercised, and chewing is done on soft foods or chewing gum. Another effective technique is finger-assisted stretching, in which fingers open the mouth gently. Consistency is the key, and working with healthcare professionals allows patients to perform exercises based on their individual needs and helps ensure slow-but-steady and safe improvement.