Anybody of any age can have TMJ pain affecting between 5% to 12% of the population, and women tend to fare worse than males(1).
TMJ stands for temporomandibular joint, it’s the joint just in front of the ear, its main function is to facilitate chewing in partnership with the teeth and the facial muscles. All three groups must work together harmoniously for the system to function optimally. For this to occur, the upper and lower teeth must meet evenly, without causing stresses on the muscles and the TMJ joints. When the balance is disrupted, the muscles and the joints will not work effectively, instead of working together, they work against each other. One common example is when a tooth is taken out, which tends to upset the equilibrium, just like taking one book from the shelve, the other books tend to move to fill the space. Initially, the body adapts, but in time, with general wear and tear of all the structures, TMJ dysfunction starts to rear its ugly head.
Other factors such as habitual clenching due to stress or trauma to the joints may upset the whole system which can lead to a downward spiral, if not treated.
As a dentist, I see malocclusion or toxic bite as one of the main causes of TMJ pain otherwise known as TMD (TMJ Dysfunction). The irony is that while there is a link between TMJD and OSA, women are disproportionately affected most by TMJD and men by OSA(2).
In the initial stages of TMJD clicking of the TMJ joints can be felt by the patient, these clicks are usually inaudible to other people near by and there is no pain, yet. The patient doesn’t usually worry too much at this stage. Most say, “Oh, it’s been there for a long time, never bothers me!”
The truth is that clicking is not to be ignored, it’s an early sign that things are not functioning optimally, one must be attuned to one’s own body and to heed any warning signs. If you hear a rattling noise in your car, it cannot be ignored, you know that it can only get worse before something breaks down.
If untreated, pain in the joints starts to develop and may be accompanied by headaches.
The intensity of the pain is determined by the adaptive capacity of the patient. While mild pain can be tolerated, especially by those with strong pain tolerance, chronic pain can lead to irreversible damage to the joints and the surrounding structures, clicking then graduates to grating (crepitus), where the disc wears down resulting in bone clashing against bone in the TMJ joints.
To understand TMJD you need some knowledge on TMJ anatomy.
In a healthy TMJ there is a space between the condylar head and the temporal bone, which is occupied by a disc. The disc is a strong and resilient fibrous tissue nestled between the temporal bone above and the condyle bone below, it acts as a cushion for the condyle to move freely during function such as chewing and talking.
Just behind the joint is the ear canal. Due to its proximity to the TMJ joints, symptoms such as ringing in the ears, dizziness and vertigo may be present.
The most common feature of TMJD is when the condylar head is pushed back, the back part of the space is compressed. This area has nerves, blood vessels and ligaments surrounding the joint area. When they are continuously being compressed every time you eat, talk and swallow, as in a toxic bite, pain can develop over time. Some people exhibit different symptoms such as headaches, migraines, ringing in the ears, vertigo.
As mentioned previously, TMD can occur at any age, but many people with a noxious bite do not seem to have the TMJD symptoms. It is feasible that the body adapts when young, but as one gets older, the adaptive capacity is fully challenged, eventually TMJD manifests itself.
Today I am seeing TMJD cases more frequently than in the past, mainly in women, but they seem to be younger and younger with time(3). I am seeing children as young as 12 years old developing TMJD. The most curious thing is that there is a significant increase in the number of young women with perfectly straight and healthy teeth developing TMJD. It does seem to negate the theory of tooth loss and worn down teeth. However one thing that remains the same is the retruded condyle, whether the teeth are straight or not.
On several occasions, I mentioned the immune system and adaptive capacity. A good diet is the key to good healing. A strong immune system is one of the keys in accelerating the healing process from chronic inflammation to a healthy physiological state, re-establishing the homeostatic balance not only of the TMJs, but the body as a whole. When pain is present it is advisable to eat any soft foods to minimise trauma on the joints and to allow rest and healing. Chronic pain usually suggests chronic inflammation giving rise to an acidic blood pH, which is low in Oxygen. It is therefore essential to neutralize the blood pH to facilitate the healing process. These are some of the healthy foods that are highly recommended in conjunction with other treatments described below(4):
Stress plays a part in TMD, directly from clenching and grinding, or indirectly from the suppression of the immune system. The effects of clenching and grinding on the TMJ joints are multiplied when a person has a toxic bite due to the excessive pressure applied on the joints.
Stress activates the sympathetic system (fight and flight), increasing the levels of stress hormones such as adrenaline and cortisol. Chronic stress does not allow the body to rest, heal, and regenerate rendering it to be chronically inflamed. All animals including humans are equipped with stress hormones to deal with immediate physical dangers, which are essential for survival. But humans are the only organism to suffer from chronic stress simply by thinking about negative thoughts, about things that haven’t happened. The body elicits the same physiological response such as high blood pressure, increased heart beat and breathing rate, whether the person is stressed from being chased by lion or by thinking about unpleasant situations even before they occurred(5). Having said this, genetics play a part in the susceptibility of TMJD to stress(6).
With pre-existing narrow airway, during the REM cycle of the sleep, the muscles tend to relax and become ‘floppy’, narrowing the airway further. A sensor in the brain stem detects a reduction of Oxygen in the blood (and an increase in CO2). As the body cannot survive without Oxygen, there must be some compensatory mechanism to ensure survival, and one way to let more in is by clenching the jaws. Clenching tightens up the throat muscles, which opens up the airway(7). These activities can occur numerous times during the night, for the sole purpose of breathing, aggravating the TMJ joints in the process. A previous blog discusses the management of sleep breathing disorders. Hidden dangers of snoring
As a dentist I tend to focus on the bite, but the patient has to be reminded that there could be other factors contributing to the pain such as poor neck and back postures. A referral to the Physiotherapist may be in order.
As discussed in “Hidden dangers of snoring” There is also a strong relationship between TMJD and airway. All TMJD patients must have their airway and sleep investigated, a 3D scan and a subsequent referral to an ENT surgeon may also be required.
If the pain is acute, an orthotic is constructed to decompress the TMJ joints, see the picture below of an orthotic worn on the lower teeth. The orthotic must be made by a trained dentist, a poorly made splint may aggravate the condition(8).
Ideally the orthotic is to be worn 24/7 to allow healing of the TMJs, for approximately 3 months.
The orthotic as shown above opens and frees up the bite, decompressing the TMJ joints.
From there the patient will weigh up the risks and benefits of a phase 2 treatment, such as orthodontics with expansion(9), jaw expansion without surgery, crowns and bridges F or full mouth reconstruction.