Unlike in the case of adults, where the majority of teeth grinding comes from stress, bruxism in children seems to be independent of pressure or anxiety. Although its cause in kids is largely unknown, it appears children can grind their teeth more out of habit, or perhaps as a soothing mechanism, rather than as a way of dealing with stress.
Another potential cause of juvenile bruxism can be the eruption of teeth. The statistics seem to bear this out: Teeth grinding is found in about 50 percent of infants as they teethe, and that number drops to about 30 percent as kids get ready to enter school. By the age of 7 or 8, the percentage drops dramatically again and by the age of 12 -- once all of the adult teeth have come in -- it typically disappears altogether [source: Minciotti].
According to the American Academy of Pediatrics, it is not usually necessary to treat bruxism in children under age 8. This is supported by the American Academy of Pediatric Dentistry who contend that the condition should only be treated "when the habit is of sufficient persistence, duration or intensity to damage the permanent teeth or cause other complications that affect the child's well-being" [source: Minciotti]. If childhood bruxism needs to be addressed, the most common treatment is a mouth guard.
For more information on topics related to bruxism, keep reading.