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NCT Number: NCT07237087

Masseter Muscle Stiffness After Heat Application and Percussion Therapy

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.

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Key information

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Zentrum für Zahnmedizin

Zurich, Canton of Zurich, 8032, Switzerland

Location status: Recruiting

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

Massage Gun

Device

The massage gun used in this study will be equipped with a soft attachment designed for use on the face, ensuring safe and comfortable application to the masseter muscle.

heat treatment

Device

The heat treatment will be applied for 20min.

Other names: heat pad, heating pad

Primary outcomes

  1. Masseter muscle stiffness

    Time frame: The time from the first appointment to the second (final) appointment will be two weeks.

    Muscle stiffness will be assessed using shear wave elastography (SWE) via ultrasound. Results will be reported in kilopascals (kPa) and/or meters per second (m/s).

Secondary outcomes

  1. Algometry of the Masseter Muscle

    Time frame: The time from the first appointment to the second (final) appointment will be two weeks.

    Algometry is the quantitative assessment of pain sensitivity, performed using a pressure algometer to determine pressure pain thresholds (PPTs) at specific anatomical sites.

  2. mouth opening

    Time frame: The time from the first appointment to the second (final) appointment will be two weeks.

    The mouth opening will be measured with a ruler.

  3. maximum bite force

    Time frame: The time from the first appointment to the second (final) appointment will be two weeks.

    Maximum bite force can be measured with a bite sensor or an occlusal force-meter, that is placed between the patients' teeth. The patient is requested to bite on the bite sensor as hard as possible. Bite force is usually measured in Newton.

  4. chewing efficiency

    Time frame: The time from the first appointment to the second (final) appointment will be two weeks.

    Chewing efficiency will be measured with a two-coloured chewing gum. The person tested will take two chewing gums simultaneously, both with different colour. The gums must be chewed 20 times and after that the mass is pressed on a glass plate and is analysed how much the colours have mixed.

Study contacts

Contact information is provided by the study sponsor or research team.

Nenad Lukic, Dr. med. Dr. med. dent.

CONTACT

[email protected]

Vera Colombo, PD Dr. sc. ETH

CONTACT

[email protected]

+41 (0)44 634 33 11

Sponsors and collaborators

Lead sponsor

University of Zurich

Other

Collaborators

  • University Hospital, Zürich

Registry information

Official study title

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

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Nov 19, 2025
Registry last updated
Nov 19, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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