Question
My child is nine and a half months old, with two teeth on the bottom and four on the top. During the day when they are not sleeping, they sometimes grind their jaws loudly. After examination, it was found that the child lacks no nutrients or toxic substances. I would like to know what could be the reason for this and how to deal with it.
Answer
Grinding teeth is caused by involuntary contractions of the chewing muscles, leading to friction between the upper and lower teeth and producing a sound. This contraction is controlled by the trigeminal nerve, and when the nerve becomes excited, it triggers the contraction of the chewing muscles, resulting in grinding.