Table of Contents
Introduction
The temporomandibular joint is on both sides of the jaw in front of the ears; TMJ connects the lower jaw (mandible) to the skull. TMJ (temporomandibular joint) acts like a hinge, helps in the lower jaw's gliding motion, and plays a significant role in chewing, swallowing, and speech.
TMJ is often called the ginglymoarthrodial joint because it permits both hinge or rotation (ginglymoid) and sliding motion (arthrodial). Even with its well-organized anatomical structures, the maximal opening of the mouth leads to subluxation or relaxation of the temporomandibular joint. Physiotherapy interventions play an important role in treating TMJ hyperlaxity.
What Is TMJ Hyperlaxity?
Increased laxity of the joint capsule in the temporomandibular joint causes hypermobility of the TMJ. Hyperlaxity of the TMJ is characterized by increased length and elasticity of the normal joint restraints resulting in increased range of motion and deviation of the joint. It might result from excessive ligament elongation, which holds the joint together.
What Causes TMJ Hyperlaxity?
TMJ hyperlaxity is caused due to excessive mouth opening while yawning, vomiting, wide biting, or people with a seizure disorder. It also occurs in trauma caused by these conditions:
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Injury to the mandible.
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Forceful hyperextensions.
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During intubations in general anesthesia.
TMJ hyperlaxity results in joint hypermobility, which can be acquired due to extrinsic or congenital factors such as generalized joint hypermobility in Ehlers-Danlos syndrome or Marfan syndrome. It can also occur in patients with other predisposing factors, such as compromised morphologic conditions of the condyle and eminence or any previous capsule or ligament injury, and patients with neurodegenerative or neuro-dysfunctional diseases or muscle dystrophies.
What Are the Symptoms of TMJ Hyperlaxity?
The clinical findings of TMJ hyperlaxity are:
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In a person with TMJ hyperlaxity, the mandible is noted to be in a sticky open position for a short period before gliding back into fossae.
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Asymmetric movements of the mandible while opening and closing.
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Sounds like clicking or popping are noted on the wide opening of the mouth.
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A dislocation occurs suddenly and repeatedly.
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Extreme pain over the joint might be noted.
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Patients find difficulty speaking, chewing, and closing their mouths.
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Excessive salivation.
What Is the Role of Physiotherapy in Managing TMJ Hyperlaxity?
A complete evaluation by the physical therapist is necessary before initiating the treatment. Treatment for TMJ hyperlaxity includes initial non-invasive therapeutic measures such as; occlusal splint therapy, medications like NSAIDs to relieve pain, behavioral changes, and self-care measures. Additionally, the patients are advised to eat soft foods and to avoid items that require excessive mouth opening (i.e., apple, corn on the cob, large sandwich) or firm biting while eating carrots and repetitive chewing motions (i.e., chewing gum).
Physical therapists perform manual therapy or incorporate it into a home regimen. Manual therapy uses manipulation, joint mobilization, and other soft tissue techniques to reduce pain, to control jaw muscles and joint proprioception. In patients with hyperlaxity of the TMJ, the condyle glides anteriorly out of its socket and remains open before spontaneously returning to the fossae or through manipulation. The physical therapists will help in the decompression of the jaw through manipulation. Few guidelines for the manipulation techniques:
Dynamic Soft Tissue Mobilization of the Masseter Muscle:
The patient is supine, and the physical therapist is behind the patient's head. In this position, the therapist will place the thenar part of both hands and the thumb finger over the mandible with other fingers placed over the occiput. Then, the physical therapist will massage the masseter muscle in caudal directions for up to 90 seconds.
The physical therapist uses manipulative techniques to control jaw muscles and joint proprioception. Firstly the therapist will help recognize the resting position of the jaw. For example, the lips are closed, teeth apart, and the tongue resting lightly on the hard palate behind the front teeth. Next, the patient is advised to breathe in and out slowly through the nose, using diaphragmatic breathing. Finally, the patient is asked to maintain the resting position throughout the day.
The patients are taught to control the jaw opening and closing through the first half of the range of motion. With the tongue on the roof of the mouth, the patient opens the mouth, trying to keep the chin in the midline. A mirror is used as a visual reinforcement. The patients are also taught to maintain symmetry between the movement of the two sides when opening and closing the mouth.
The physical therapist performs extra-oral massage in the masseter or the temporalis muscle region to facilitate muscle relaxation. If the jaw deviates while opening or closing the mouth, the patients are taught to practice deviation of the jaw to the opposite side.
The physical therapist will advise strengthening exercises for patients with TMJ hyperlaxity. During the depression, elevation, and lateral movements, resistance is given in the opposite direction. This exercise is recommended to repeat several times during the day.
What Are the Other Treatment Modalities of Physiotherapy?
Physiotherapy management for TMJ hyperlaxity includes electrophysical agents, manual therapy, and exercise. Physical therapists use electrophysical agents like:
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TENS (transcutaneous electrical nerve stimulation).
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Ultrasound therapy.
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Biofeedback training.
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Low-level laser therapy.
Electrophysical Agents
- TENS (Transcutaneous Electrical Nerve Stimulation):
Physical therapists use transcutaneous electrical nerve stimulation as one of the most critical modalities in managing pain. TENS stimulates the nerve cells that block the transmission of pain signals and modifies pain perception. This therapy is primarily used to relieve long-lasting pain and relax masticatory muscles in the injured area. However, the effectiveness of TENS in TMJ pain is still questionable.
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Ultrasound Therapy:
Ultrasound therapy creates a heating effect by sending high-frequency sound waves not audible to the human ear. With this heating effect, ultrasound therapy promotes improved healing by increasing the blood flow in the deeper tissues.
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Biofeedback Training:
Studies indicate the use of biofeedback training by physical therapists in treating TMJ hyperlaxity as a method to facilitate muscle relaxation in the temporomandibular joint. This therapy places the electrodes unilaterally or bilaterally on the masseter muscle. Various relaxation techniques are used in biofeedback therapy, such as progressive muscle relaxation, wherein the patients are asked to tighten and relax different muscle groups alternatively. This technique is advised in patients with altered muscle activity in the temporomandibular joint.
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Low-Level Laser Therapy:
Low-level laser therapy is a non-invasive and complementary therapy for treating TMJ hyperlaxity patients. This therapy uses a red and infrared wavelength beam to a target area at a specific dose, frequency, and intensity. This technique promotes soft tissue healing at the target area.
Conclusion
TMJ hyperlaxity can affect the quality of life and disturb our daily activities. It can lead to difficulties in speech, eating, and even closing the mouth. Physiotherapy is a safe and effective supplementary intervention and prevention modality in patients with TMJ hyperlaxity. The important recommendation in hyperlaxity patients is to avoid opening the mouth excessively. Physiotherapy helps strengthen the muscle around the TMJ for joint protection.
