Masseter Muscle Stiffness After Heat Application and Percussion Therapy

Effects of Heat Application and Percussion Therapy on Masseter Muscle Stiffness Measured With Ultrasound Shear Wave Elastography

The purpose of this study is to evaluate the changes in the stiffness of the masseter muscle (a jaw muscle) before and after two types of treatment: applying commercial heat pads or using a commercial massage gun.

We will measure the muscle stiffness on the surface of the muscle using a special ultrasound probe, with a method called shear wave elastography.

When this muscle is too stiff, it's often linked to jaw pain and problems with the jaw joint - a condition known as Temporomandibular Disorder (TMD).

The goal is to find better treatment options for people with TMD and to collect data using this imaging technique.

In our study, participants will be randomly assigned to one of two groups. This is important to ensure reliable results and is called randomization.

The two groups are as follows:

Group A:

First, the stiffness of the masseter muscle in the cheek is measured using ultrasound. Then, we will assess the mouth opening, the muscle's sensitivity to pressure, bite force, and chewing efficiency using several short tests. After that, the masseter muscle will be treated with a massage gun with a soft attachment for 2 minutes. All tests will be repeated after the treatment.

Group B:

First, the stiffness of the masseter muscle in the cheek is measured using ultrasound. Then, we will assess the mouth opening, the muscle's sensitivity to pressure, bite force, and chewing efficiency using several short tests. After that, the masseter muscle will be treated with a heat pad for 20 minutes. The heat pad will be held in place with a strap, and participants may sit and read or relax during the treatment. All tests will be repeated after the treatment.

Each participant will receive both treatments (massage gun and heat pad), but in a different order depending on group assignment. There will be a two-week washout phase between the two treatments to ensure that the effects of the first treatment do not influence the second.

Inclusion Criteria:

• Willingness to participate to the study
• Signed written informed consent

Exclusion Criteria:

• Inability to follow procedures or insufficient knowledge of project language, inability to give consent
• a history of drug ingestion within the past week (e.g. pain relievers, muscle relaxants, botox and anti-inflammatory drugs)
• systemic diseases
• Contraindications listed on the massage-gun instruction manual systemic and related to the use on the masseter area.