TMJ – Temporomandibular Joint Dysfunction
Temporomandibular joint dysfunction, commonly abbreviated as TMD or TMJD is an umbrella term that covers the dysfunction and the pain in muscles of mastication which are the muscles responsible for the movement of the jaw, and the temporomandibular joints which are the joints that connect the mandible and the skull. The most significant feature of this condition is the pain which is followed closely by the restriction of the mandibular movement and the noises coming from the TMJ or the temporomandibular joints when the jaws are in motion.
Albeit it is not a life-threatening condition, TMJD is detrimental to an individual’s quality of life especially when the symptoms are chronic and challenging to deal with. About 20%-30% of adult population is affected by this condition to some level with the largest group being 20 to 40 years old. TMJD is experienced by more women than men and after dental pain; it is the second most common condition behind orofocal pain.
There are suggestions that TMJD might develop as a result trauma especially after a whiplash injury but the evidence is not conclusive enough. This type of TMJD is referred to as posttraumatic TMD or pTMD and in some cases it is also called idiopathic TMD or iTMD. The muscle related TMD is also referred to as myogenous TMD and is distinguished from joint TMD also called arthogenous TMD. The reference is based on whether the TMJs or the muscle of mastication are involved.
Signs and Symptoms
There is a variation in the presentation of signs and symptoms of the temporomandibular joint disorder. In most cases, the symptoms will involve more than one of the different parts of the masticatory system, ligaments, connective tissues, teeth, bones, muscles, nerves and tendons. The cardinal signs and symptoms described are:
- Tenderness and pain on palpation of muscles of mastication or pain of the joint.
- Limited movement of the mandibular which results in difficulty of talking and eating
- Joint noises from during movements of the mandibular. The noises are popping, grating or clicking.
There are other signs and symptoms which have been described though they occur less often and are less significant when compared to the cardinal symptoms. These include:
- Pain experienced elsewhere such as the shoulder, teeth or neck
- Diminished auditory acuity or hearing loss
- Headache such as migraine, tension headache, or pain in the occipital region and myofascial pain.
- Pressure or pain behind the eyes.
- Malocclusion sensation or a feeling that the upper and lower teeth are not meeting properly.
Some medical experts believe tat TMJD is among the four major symptom complexes in chronic orofocal pain together with atypical facial pain, atypical odontalgia pain and burning mouth syndrome. This condition has been considered to be a rheumatological, musculoskeletal, or a neuromuscular disorder. In some cases, the condition has been referred to as a psychogenic disorder and a functional pain syndrome. There are some medical experts that refer to the condition as a central sensitivity syndrome because of the belief that TMJD might be caused by centrally mediated pain sensitivity.
There are hypotheses that place TMD as having a number of similarities with pain syndromes such as irritable bowel syndrome, fibromyalgia, headache, chronic neck pain, interstitial cystitis, and chronic back pain. These disorders often occur together and there is a theory that they occur as a result of centrally mediated pain sensitivity.
Causes of TMJ Disorder
TMJD is referred to as a symptom complex which means that it is a group of symptoms which characterize a particular disease and occur together. The cause of TMD is believed to be a collection of factors which are not well understood and the etiology of the condition is not known. There are factors which are believed to predispose to the condition such as hormonal, anatomical and genetic, factors which are believed to precipitate it such as occlusal changes, trauma and parafunction, and factors which appear to prolong TMD such as parafunction and stress. There are two hypotheses which have dominated TMD research the occlusal disharmony theory and the psychosocial model. The occlusal disharmony theory has since become a subject of controversy as a result of lack of enough evidence.
There are different diagnostic systems used in the diagnosis of temporomandibular joint disorder. Research Diagnostic Criteria is the method considered a gold standard for this condition. This method involves two axes: axis I which involves the physical diagnosis and Axis II which involves psychologic diagnosis. Some of the important elements that are used in the diagnosis include pain experience in the muscles of mastication, mandibular movement limitation, noise from the TMJs during movement of jaws, joint capsule tenderness on one of both of the TMJs among many others.
TMJD has proved to be a difficult condition to manage especially because this disorder cuts across the boundaries of two disciplines in health care in particular neurology and dentistry. For this reason, successful treatment is often multidisciplinary and involves various medical approaches. Most of the experts that have treated or are treating TMD have come to a conclusion that the treatment direction taken should not permanently change the jaw or teeth and the procedure used should be reversible. To avoid the permanent alterations, prescription or over the counter medications are used in managing this condition. Occlusal splints also referred to as intra-oral appliances or bite plates can be used by dentists to management and treat TMD.
Medication is the main method used in the management of pain caused by TMD. This is because there is little or no evidence of the effectiveness of other treatment methods such as surgical procedures or dental intervention. There are many drugs that have been used in the treatment of TMD such as analgesics, anticonvulsants, muscle relaxants, benzodiazepines, among others.
The most important thing is to ensure that any individual with signs and symptoms of TMD sees a qualified medical practitioner for better diagnosis, management and treatment of the condition using the correct and approved treatment methods.