Possible Causes of Craniomandibular Dysfunction
The causes of craniomandibular dysfunction are varied, and in some cases are hereditary or present at birth.
1. Causes of CMD present at birth or hereditary:
- birth trauma
- false bite
- crooked teeth
- anomalies of the jaw and face
- skeletal anomalies, i.e. differences in leg lengths and scoliosis
2. Other causes of CMD:
- arthritis of the joints
- previous damage to the spinal cord
- whip-lash from an accident
- improper dental replacement
- grinding-induced decrease in tooth height
- orthodontic treatment
- improper leg length compensation technique
If the lower mandible assumes a different position, the entire statics of the body may become imbalanced (descending dysfunction). The reverse is also possible: a functional disturbance in a different region of the body can lead to disturbances and pain in areas of the head, the chewing muscle, and the mandible joints (ascending dysfunction). Chronic headaches, migraine-like attacks, noise in the ear, dizziness, and difficulty in swallowing are the most common symptoms.
Among the most important and dangerous causes of CMD are the so-called “parafunctions” (Bruxismus), which are forceful tooth contact over many hours each day or night unrelated to chewing food. Here one differentiates between tooth pressing and grinding.
In the case of tooth pressing, the tooth rows are pressed firmly together for several hours. During tooth grinding, teeth are rubbed together forcefully for longer periods. These phenomena occur unconsciously. The forces operating on the teeth are comparable to a weight of more than 300 kg being applied to the teeth over several hours. The teeth become sensitive and the muscles tense. Head and neck pain develop (particularly in the morning). Additional stress or physical exertion can significantly amplify the symptoms. A chain of reactions is set off, which is hard to stop.
The cause of tooth grinding or pressing in 50% of the cases is a disturbance in the tooth rows, in 12% of the cases is a disturbance in the mandibular joint, and in 38% of the cases there is a psychological reason.
Who can be affected by CMD?
In principle, children and adults of all ages can be affected by CMD. Young to middle-aged women are the most common CMD patients (eight times more women than men are affected by CMD). It is not scientifically understood why this is so. Endocrine and hormonal aspects are being discussed, as well as to a lesser extent stress-related reasons and the multiple responsibilities of women combining family and career. Regardless of gender, people suffering from work-related stress or stress from examinations or going through a life crisis of some kind have a higher risk of acquiring CMD. Particularly through parafunctions or elevated muscle activity during psychological stress CMD my be initiated. An improper dental treatment is often the trigger for CMD. For instance, crowns, bridges, prostheses or even fillings, which are too high or too low, can trigger CMD within a short time after treatment.
If a new filling is too high, so-called “mechanic receptors of the gums” register the slightest deviation and send this information via nerve canals to the central nervous system. This could lead to an altered movement pattern of the lower mandible in order to avoid the disturbance, which could subsequently lead to painful chewing muscle or a painful jaw joint. Alternatively, the jaw joint could be worn away by the increased muscular activity and inflammation of the joint could develop.