When he's excited and running around, our 3.5yo son "clacks" his teeth. I don't have a better way of describing it! It's just really forceful, rapid, loud biting. He bites 5-10 times, then stops, then again a few times, etc. In total maybe 3-5 times a day. He also tends to jut out his lower jaw when doing it. He doesn't show any signs of tooth trouble like sensitivity or chewing things. We brush regularly and have checkups. It's literally only when he's excitable. So even if it doesn't sound like a constant behaviour, I am concerned because I don't want him to crack his enamel or bite his tongue, or for this silly habit to persist! Have asked him why he does it but he has no answer (he's perfectly able to explain himself otherwise). Explaining that we have to look after teeth, that it's painful to have them fixed if they are damaged, etc. have no effect. Also, this is not bruxism according to its definition (gnashing/ grinding/ clenching, esp. when asleep). Has anyone else had this same issue, and what did you do?