Continuing Education Activity

The temporomandibular joint is pivotal towards mastication and vocalization. Dysfunction in this joint can occur with macrotrauma, microtrauma, or maladaptive behaviors. A myriad of treatment options exist, both invasive and noninvasive. This activity reviews the evaluation and treatment of temporomandibular dysfunction and highlights the osteopathic provider's role in evaluating and treating this condition utilizing muscle energy, myofascial release, and balanced ligamentous technique.

Objectives:

• Describe TMJ as a frequent cause of headaches and pain with mastication.

• Review key anatomical landmarks associated with the TMJ and the role they play in osteopathic treatment.

• Outline the steps needed to perform a physical exam specific to the TMJ.

• Summarize the different healthcare providers that can assist in both the diagnosis and treatment of TMJ.

Introduction

Muscle Energy Technique (MET) is an active technique of osteopathic manipulative medicine that engages restrictive barriers without stressing the system. The patient voluntarily applies a precise muscle effort from a specific position in a specific direction opposite to a counterforce. MET can lengthen the spastic and weakened muscles and mobilize restricted joint motion in the temporomandibular joint (TMJ) area. The required amount of force ranges from minimal to maximum contraction. Myofascial release (MFR) is a passive maneuver applied to the TMJ that requires stretching and reflexing the soft tissues and joint restrictions. The physician twists, truncates, and compresses the TMJ while repetitively palpating the tissue and joints, which eventually converts tightness and looseness. Balanced ligamentous tension (BLT) is both a passive and active technique that exaggerates the TMJ dysfunction; the ligaments guide temporomandibular muscle movement, and BLT utilizes this fundament to restore order. MET, MFR, and BLT techniques are sparsely reported in medical literature and successfully minimize TMJ and affiliated regional pain.[1]

Dentists have reported TMJ dysfunction in dental literature since the 1950s, initially termed temporomandibular dysfunction; it involved malocclusion of the teeth (imbalance between the upper and lower teeth). Experts later discovered that this mechanism alone was not enough to account for all clinical findings found in the condition. About 20 years later, in 1979, it was conceptually designated as an orthopedic condition. TMJ disorders are still coined temporomandibular disorders (TMD), containing all TMJ problems and related structures. OMT (osteopathic manipulative therapy) mobilizes the compromised TMJ through the dysfunctional pathologic barrier (not after its usual physiological barrier), leading to low injury reports off OMT procedures. This review explores the usage of OMT in treating TMD.[2][3]

Anatomy and Physiology

Key landmarks derive from the temporal bone and mandible.

• Areas to recognize on the temporal bone palpation include the mastoid process, parietal notch, and zygomatic process. Important landmarks that are non-palpable include the external acoustic meatus, occipital mastoid suture, spheno-squamous pivot, mandibular fossa, and eustachian tube.
• Palpable areas to recognize on the mandible include the ramus, angle, body, articular eminence, and mental protuberance. Non-palpable areas that remain clinically important include the condylar process, articular cartilage, medial and lateral collateral ligaments, stylomandibular ligament, and sphenomandibular ligament. Internally, the lateral temporomandibular ligament and joint capsule balance the sphenomandibular ligament. Inferiorly, the mandible angle is connected to the styloid process by the stylomandibular ligament, which contracts and extends to allow for the hinge and gliding action resulting in jaw opening and closing. When full jaw flexion (opening) displays on magnetic resonance imaging (MRI), the region resembles a "bow-tie" with the articular disc seeded inside the anterior condyle at its mid-point. With jaw-closing or extension, the disc's posterior aspect eventually lines up perpendicular to the anterior condyle. Pathology typically presents in the form of hyperextension resulting in bite blocks advised for prevention.[4][5]

Many patients suffering from TMJ have an overbite, classified as Class II in the dental literature. Class I patients have little to no overnight, whereas class III an underbite with protrusion of the lower teeth.

While osteopathic manipulative treatment focuses on the joint itself, it also involves treatment of the muscles, which are also affected secondarily affected by the joint dysfunction.

• The muscles of mastication, controlled by cranial nerve V, include the temporalis, masseter, lateral pterygoid, and medial pterygoid.
• The temporal muscle originating at the temporal fossa and inserting on the medial aspect of the mandible's ramus and coronoid process.
• The masseter assists with mastication and originating on the zygomatic arch and maxilla and inserting on the posterolateral aspect of the mandibular angle.
• The lateral pterygoid and medial pterygoid muscles originating on the greater wing of the sphenoid and medial aspect of the lateral pterygoid plate of the sphenoid, respectively, and inserting on the mandible.
• The TMJ's functions are opening, closing, protrusion, retrusion, lateral motion, and chewing.
• Opening – depression, or dental flexion, a hinge, and glide motion allowing the jaw to drop appx 50mm, which estimates as 3 MCPs of the dominant hand. On CT or MRI imaging, the joint itself has a "bow-tie" appearance.
• Closing – elevation or dental extension.
• Protrusion and retrusion- represent the forward and backward motion of the joint.
• Lateral motion
• Chewing – requires all four muscles of mastication.

Indications

The physician must assess the patient's posture, which is a crucial indication of TMJ dysfunctions. Facial symmetry or asymmetry is the primary indication of TMJ dysfunction. Any somatic dysfunction that leads to exaggeration or restriction of motion may act as an indication. Specifically, the following conditions may initially indicate TMJ dysfunction:

• TMJ restriction-led pain
• Mandible restriction
• Neck pain

In cases of temporomandibular dysfunctions, the physician goes through a thorough observational phase by palpating the TMJ during the mouth's opening and closing. There is a noticeable midline deviation of the mandible in cases of dysfunctions with complaints of pain. The physician may also hear clicking and popping sounds during mouth opening. Abnormalities may specifically appear in:

• Cervical spine
• Occipital joint, C2, and C3
• Cranial bones
• Noticeable via craniosacral motion
• Highlighted within temporal bones and muscles, including:
• suprahyoid muscles
• ipsilateral temporalis
• masseter
• medial and lateral pterygoids

The physician may also check for tenderness within shoulder muscles along with assessing for muscular spasms or imbalances. The patient's jaw measurements may also indicate dysfunction; an average adult can open their mouth up to 40 mm in length.[6]

Contraindications

Even though popularly used, facial muscle energy is an active and direct intervention to the pathological barrier. Muscle energy technique requires the physician to employ some emphatic forces. The physician must take the responsibility to reconsider this intervention if the patient has the following:

• Low vitality
• Jaw fractures
• Unstable joints
• Acute surgical record

MFR, although passive, can be a direct or indirect intervention. MFR, therefore, is not suitable for patients of all ages and conditions. The physician must reconsider treatment if the patient has:

• Healing fractures
• Advanced diabetes
• Severe osteoporosis
• Rheumatoid arthritis
• Malignancy
• Aneurysm

BLT is a passive, direct/ indirect intervention. It is much tolerable compared to other active alternatives. However, some patients may not be suitable for the procedure if the patient:

• Refuses consent
• Has acute jaw fractures 
• Shows temporal bone malignancies
• Has a history of osteomyelitis[7]

Equipment

• An exam table
• An OMT table
• A massage table
• An alternative location that comforts the patient in sitting allows the physician to perform the technique with comfort.

Personnel

• A patient who has submitted official consent, both verbal and written.
• A chaperone may observe the procedure. 
• A physician (DO or MD) who received formal training in OMT during medical school or postgraduate medical training.
• Non-physician osteopaths may also perform these techniques in some countries.

Preparation

• Verify that the patient is fully aware of the procedure.
  • Inform the patient about the risks, benefits, and alternative therapeutic interventions available for the condition.
• Collect formal consent from the patient for the procedure.
• Check that the area of performance is well-sanitized.
• Create friction against surfaces to warm hands before applying OMT.

Technique or Treatment

Facial MET for the TMJ

       With the patient in a supine position:

1. Sit at the head of the table and instruct the patient to slowly open the mouth to observe exaggerated deviation to the side of the restriction;
2. Slowly translate the mandible in neutral, flexion, and extension to identify a TMJ restriction;
3. If dizziness or nausea appears, discontinue the procedure;
4. With support from your hand opposite to the barrier, mobilize the lateral mandible into its flexion-extension along with restrictive barriers using the right index and middle fingers; instruct the patient to slowly open their mouth from the restriction against your equal resistance for 3 to 5 seconds;
5. The patient should relax and then push the mandible to a new side-bending restrictive barrier;
6. Repeat this counteractive contraction and stretch 3 to 5 times or until the barrier is engaged;
7. Reassess TMJ motion to confirm the engagement.

Direct MFR for the TMJ

       With the patient in a supine position:

1. Sit at the head of the table and gently hold the mandible with one hand and the opposite mandible with your other hand;
2. Gently abduct the mandible, holding a firm and static force at the barrier until tissue release finishes;
3. Slowly rotate the mandible and move it into additional abduction, keeping the steady force at the barrier until tissue release finishes;
4. Gently adduct the mandible while keeping external rotation, applying steady force at the barrier until tissue release finishes;
5. Slowly restore the mandible to a resting position and reassess the TMJ in motion for checking engagement.

BLT for the TMJ

       With the patient in a supine position:

1. Apply the vault hold to palpate the TMJ joint to assess asymmetry of motion;
2. Since this is indirect, softly exaggerate the membranous asymmetry;
3. Resume exaggerating membranous asymmetry and blockading return to neutral position until the TMJ stops at a static point;
4. Hold this position until the TMJ returns and then softly follow it back to the neutral position before relieving the pressure;
5. Reassess the TMJ and its membranes for the return of symmetry.[8]

Complications

OMT-led injuries are rare in the literature; a retrospective study of cases administered between 1925 and 1993 reports only 185 injuries caused by OMT. Acute soreness is sometimes apparent in patients after OMT; in fact, any form of manual medicine leads to this soreness. The degree of soreness will vary, as it solely depends on the approach, angle, and force applied by the physician or non-physician therapist. Passive interventions like BLT procedures are generally risk-free; however, active interventions such as muscle energy may cause minor musculoskeletal complications.

Muscle energy procedure is the most risk-bearing in this band of procedures, requiring the physician to apply direct exertion. Medical literature reports one deleterious result per 50,000 active interventions; however, there is no strong evidence suggesting that active manual interventions performed by well-trained physicians (DO or MD) and providers should go through revision due to high risk. Proper warm-up before and adequate hydration after OMT procedures will minimize soreness; experience will enhance the physician's or provider's skills and lead to better performance, as well.[9][10][11]

Clinical Significance

Muscle energy uses the patient's muscle energy to control a pathological barrier via reciprocal and autogenic inhibition. Administered by various manual therapists, including physical therapists, physiotherapists, non-physician osteopaths, this method has undergone randomized control trials to prove its efficacy. Phadke et al. analyzed the effect of muscle energy procedures and static stretching on pain management and functional disability on patients with mechanical neck pain, similar to symptoms seen in TMJ dysfunctions. The team concluded that MET was better than the static stretching techniques used by professionals, judging outcomes using VAS and Neck Disability Index (NDI).[12]

Direct MFR is mainly used to stretch and minimize muscle tightness; yet, its analgesic effect is noteworthy. In a cytochemical investigation, scientists discovered intercellular fibroblasts responding by secreting inflammatory cytokines, surpassing hyperplasia, and modifying cell shape and alignment. An in vitro study showed that MFR-led release of strain for 60 seconds reversed inflammatory effects in previously strained cells. Current trials have shown that MFR may promote wound healing by affecting the extracellular matrix.

BLT procedure deunionize and exaggerate the area of dysfunction. As one of the least demanding techniques, BLT works the best in hospital settings. Especially if the TMJ dysfunction is too severe to the point where the patient may be unable to cooperate with the physician, BLT will help the physician treat the patient. The Multicenter Osteopathic Pneumonia Study in the Elderly (MOPSE) RCT demonstrated briefed hospitalization and reduced in-hospital mortality rates within experimental subgroups, supporting OMT's contribution as a supplementary treatment for hospitalized pneumonia patients.

Enhancing Healthcare Team Outcomes

Western surgical and medicinal interventions are effective in pain management for TMJ-related disorders; however, both DOs and MDs undermine OMT's pain-free application in clinical practice and pain management relating to TMJ dysfunctions. There are a few significant reasons why DOs (osteopathic physicians) less-frequently practice OMT after medical school graduation and residency completion:

• Lack of conjoining between osteopathic principles and clinical concepts in the medical, educational process.
• Extended periods of graduate medical training that fissions students from the traditional classroom-based OMT experience.[13] [Level 4]

Despite an official merger between osteopathic (DO) and allopathic (MD) graduate medical education, no official steps integrate OMT practice in the form of a rotation across ACGME-accredited residency programs. DOs and MDs both learn Western, allopathic medicine and surgery to graduate medical school; yet, MDs have traditionally stayed away from practicing OMT, the only skill that differentiates an MD and a DO. Understanding and implementing the side-effect-free analgesic benefit of the OMT would allow for a broader approach to clinical practice and offer the patients various treatment options.

Nursing, Allied Health, and Interprofessional Team Interventions

A variety of healthcare professionals and medical specialists manage TMJ dysfunctions. Dentists, especially oral surgeons, can contribute to pain management when OMT may not work; for instance, a chronic degenerative joint disease in the TMJ may not respond to OMT. General dentists may develop custom bite splints to encourage proper chewing, leading to long-time healing and prevention of any further deterioration. Neurologists who have completed fellowship training in neuromuscular medicine or pain medicine may also contribute to the treatment. It is not uncommon for TMJ pain to radiate and convert into a headache. In such cases, TMJ joint blocks may minimize the pain. Internists, psychiatrists, pediatricians, or neurologists who have completed an advanced fellowship in sleep medicine may encourage anterior advancement of the lower jaw to minimize obstructive sleep apnea caused by TMJ pain or dental implants.

Acupuncturists have developed a method of maximizing TMJ functions by intervening in points located at the iliotibial tract along the right lower extremity, named GB31. Physiotherapists can work towards relieving musculoskeletal pain and normalize ROM via posture correction and full opening exercises. TMJ pain instigates via psychological mechanisms. Behavioral health specialists may minimize stressors that lead to an incorrect posture or movement, which creates the pathologic barrier. Occupational therapists may help the patient make lifestyle changes that contribute directly to the stressors; a change of sleep posture or workplace movements may minimize further microtears.[14][15][16][17]