Temporomandibular joint disorders (TMD)
What is TMD?
The temporomandibular joint (TMJ) connects the upper jaw to the lower jaw and consists of bone, an articular disc in between for cushioning, and synovial fluid that acts as a lubricant. The TMJ is surrounded externally by a fibrous capsule and is attached to several muscles that help to control jaw movements. Any disorder that involves the TMJ and/or surrounding muscles is called temporomandibular joint disorder or “TMD”. Patients with TMD may experience pain, swelling, limited movement on opening and/or closing of the jaw, and jaw locking. These symptoms can have a significant impact on eating and overall quality of life. Approximately 5-10% of the population will experience TMD at some point during their lifetime that is severe enough to seek treatment.
TMD can be broadly classified based on whether the source of symptoms comes from the surrounding muscles, as in myofascial pain, or from the joint, in which the position and condition of the articular disc and surrounding structures are altered.
What is myofascial pain?
Myofascial pain refers to pain of the masticatory muscles that support jaw function, with the pain often presenting as “trigger points,” or specific areas along the muscle that are tender to palpation. Myofascial pain is unique from other temporomandibular disorders in that it is a pain of muscle origin, rather than a problem with the joint itself. Patients with myofascial pain may experience symptoms such as facial pain, limited jaw movement, or muscle tenderness and stiffness, with the clinical examination and imaging revealing no evidence of anatomic pathology with the joint. Myofascial pain tends to be a chronic condition, most commonly caused by muscle hyperactivity and habits such as grinding or clenching.
What is disc displacement with reduction
In disc displacement with reduction, the articular disc that cushions the TMJ is displaced forward in front of the condyle (the ball-shaped bone on the top of the lower jaw) when the mouth is in closed position. However, the disc is able to snap back or “reduce” to its normal position upon mouth opening, causing the popping noise. Patients may experience chronic clicking and popping of the TMJ on one side or both sides, not only during opening, but sometimes during closing, which corresponds to the movement of the displaced disc. This typically occurs without pain or limitations in jaw movements. Although it is the most common TMD subtype, most patients are asymptomatic and treatment is not usually necessary.
What is disc displacement without reduction?
In disc displacement without reduction, the articular disc is displaced forward in front of the condyle when the mouth is in closed position, but never returns back to its original position in such a way that it can block the movement of the jaw and limiting mouth opening. Patients may or may not experience clicking and popping of the TMJ during jaw function, in addition to either limited ability or inability to fully open the mouth. Pain and discomfort is common. This subtype can be acute or chronic and is often described as closed lock of the jaw and generally requires treatment if it is causing pain, discomfort and/or interfere with function.
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Other less common conditions
There are other conditions of more acute presentation that are uncommon, such as degenerative joint disorders. Inflammatory degenerative joint disorders include conditions like synovitis and capsulitis. Synovitis refers to an inflammation of the synovial fluid that lines the TMJ, leading to an acute joint pain during jaw movement and at rest. Capsulitis is an inflammation of the capsule covering the condyle, which can also cause pain and swelling of TMJ. Other systemic conditions, like osteoarthritis, can affect the TMJ causing non-inflammatory degenerative joint disorder, and have similar presentation of pain, limited mouth opening and/or TMJ swelling.
Condylar dislocation (“lockjaw”) may occur acutely when the mandibular condyle is opened too and moves far forward and is unable to go back to the socket (original position). Such cases are often acute, and seen in the emergency room for treatment. Some patients have chronic dislocation but the patient has become so used to it and the tissues around the joint have become loose so that patient is able to get the mandibular condyle back to the socket by herself/himself.
What causes TMD?
In most cases, it is not clear what causes TMD. Some possible risk factors include developmental defects in the joint or supporting bone, degenerative joint diseases (“wear and tear” on the body as in osteoarthritis), and systemic autoimmune diseases affecting the joint such as rheumatoid arthritis. Inflammation of the joint due to direct trauma to the jaw (such as a blow to the jaw) or indirect trauma (whiplash injury or chewing and grinding habits either during the day or at night) are considered additional risk factors. On rare occasions, patients can experience pain in the jaw joint due to other causes, such as referred pain from nearby infections such as sinusitis, ear infection, infections of the teeth or rarely, a tumor.
How do we know it is TMD?
A dental specialist can usually diagnose TMD based on a good history as well as a thorough clinical examination of the joint, jaws, and the surrounding structures involved in chewing. In some cases, imaging studies, such as a panoramic radiograph, MRI, or CT scan, are performed to help in the diagnosis.
​How do we treat TMD?
There is no cure for most types of TMD as it tends to be a chronic condition, though treatment varies depending on the type of TMD that you have. Treatment options include, but are not limited to the following: physical therapy such as jaw stretching exercises, moist heat packs, and/or anti-inflammatory medications to help relieve pain and reduce TMJ inflammation. Muscle relaxants are often helpful in cases where muscle spasm and resultant pain is a contributing factor. In acute inflammatory TMD conditions, treatment with steroids may be indicated either locally through trigger point injections to the joint or by taking medication. Eliminating contributing factors, such as grinding/clenching habits (bruxism) by using a night guard to relieve TMJ compression is beneficial in most cases. Fortunately, TMD tends to be self-limiting and the goal in treating TMD is to reduce and alleviate your pain and discomfort, improving your opening and improving your ability to eat, swallow and speak. Only very rare cases require surgery.
Acute TMD disorders such as synovitis and capsulitis are treated with a short course of systemic steroid treatment and anti-inflammatory medication. Usually, this approach will help to expedite healing and resolution of symptoms.
Bruxism
What is bruxism?
Bruxism, known as teeth grinding, is the involuntary action of grinding or clenching on teeth during the day, at night or both. The exact cause of bruxism is unknown but believed to be related to stress and anxiety. The severity of bruxism has been reported to be related to stress level. For example, students during exams are more likely to experience bruxism versus non-exam days. Recent research has indicated a possible role for genetics in bruxism as well.
Most people with bruxism are aware of their grinding habit or have been told so by their sleeping partner. Other symptoms may include waking up with headache and experience jaw or teeth soreness. On clinical examination, your dentist may notice mobility or “wearing spots” on your teeth which indicate bruxism.
How do we treat bruxism?
Following diagnosis, your dentist may suggest several treatment options including a night guard, behavioral and physical therapy. Considering bruxism as a chronic condition, the treatment time varies and ranges between few weeks to months. For more difficult and severe cases, your doctor may prescribe a medication to help with your symptoms, stress/anxiety suggest a psychiatric consultation. In some cases, stress-relieving mechanisms such as yoga and aquapuncture may help with bruxism.
For advanced and severs cases, long-term bruxism without treatment may result in fracture or teeth mobility, or loss of existing restoration.
Burning Mouth Syndrome
What is burning mouth syndrome?
Burning mouth syndrome (BMS) is a benign condition that presents as a burning sensation in the absence of any significant clinical findings. BMS affects approximately 1% of the population with women being seven times more likely to be diagnosed than men. The majority of patients are menopausal or post-menopausal, although men and premenopausal women may also be affected. No one really knows what causes BMS. However, it is believed to be a form of neuropathic pain. This means that nerve fibers in your mouth, for now, are functioning abnormally and transmitting pain despite the fact that there is no painful stimulus.
Contributing factors seen in half to three-quarters of patients include menopause (in females), adverse life events (loss of job and illness or death of a family member or spouse), anxiety and depression and psychiatric disorders. Some patients will also report trouble going to sleep and staying asleep throughout the night. BMS is not caused by dentures or infections and hormone replacement therapy is not effective in managing BMS in post-menopausal women.
For most patients, burning is experienced on the tip, sides and top of the tongue, roof of the mouth, and/or the inside surface of the lips, although the pattern is highly variable and burning may occur anywhere in the mouth. Patients often describe a sensation of having burnt the mouth with hot food; this may be accompanied by a perception of swelling of the tongue or throat and/or a sour, bitter, or metallic taste. The mouth may also feel dry.
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How do we treat BMS?
There is no definitive cure for BMS. We can however, reduce the discomfort using a variety of medications, many of which are used to treat anxiety, depression, or other neurologic disorders. The medications help to reduce the activity of nerve fibers. One of the medications that you may be prescribed is clonazepam (Klonopin), which is similar to diazepam (Valium). Clonazepam is generally considered first-line therapy for BMS and can be taken systemically in tablet form or used topically, as an oral rinse. Alternatives to clonazepam include amitriptyline (Elavil), nortriptyline (Aventyl, Pamelor) and gabapentin (Neurontin). Several over-the-counter remedies have also been reported that might offer some amount of symptom relief. Alpha lipoic acid (300 mg twice a day) is used to treat other neuropathic pain conditions although study results in BMS have been mixed.
Another treatment that may help you is topical capsaicin, an ingredient in hot chili peppers, Tabasco sauce, and a medication called ZostrixÔ. A simple regimen is to dissolve 5-6 drops of Tabasco sauce in 1 teaspoon of water and rinse your mouth with it four times a day. The initial feeling is one of increased burning but within a few minutes, some patients report that the burning is much reduced overall. Dry mouth products (e.g Oral Balance, a Biotene product) may help relieve the sensation of dryness and often lessens burning feeling.
