The exact cause of bruxism is not known. Abnormal alignment of teeth and psychological factors may cause Bruxism.
Researchers are divided about the cause of bruxism in children. A team of researchers associate bruxism with growth and development. They pin down the root of the problem to misalignment of the teeth on the upper and lower jaw. As opposed to this, some researchers relate the condition with the body's response to emotional problems, stress, pent-up anger, allergy or even pain which could manifest as grinding of the teeth. Fortunately, children grow out of the problem even before the appearance of permanent teeth.
The cause of bruxism in adults is thought to be connected to a condition called malocclusion that denotes misalignment of the upper and lower teeth.
The presence of parasites in the abdomen, especially pinworm or threadworm, can also cause bruxism. This is common among children.
Psychological factors may trigger Bruxism.
Stress, anxiety and anger are the most common causes. The other causes are:
Suppressed anger or frustration
Highly competitive "Type A" personalities (achievement-driven, extremely competitive and ambitious, aggressive, impatient, and highly conscious of time)
Some sleep disorders
Dental problems (improper alignment)