Several things can cause you to grind your teeth during the day or night.
Some things that can cause you to grind your teeth are stress and anxiety as when you're stressed out or suffering from anxiety you can move your teeth around and then grind them even without thinking about it.
I grind my teeth when I'm stressed and I started using a teeth guard in my mouth to stop the teeth grinding.
You can also use a pacifier in your mouth to help stop your teeth grinding at night or in the day when you're stressed.
They do make adult sized pacifiers which do help with stress and anxiety.
Pacifiers are not just for babies and I also have an adult pacifier that I put in my mouth when I'm stressed out and start grinding my teeth and it really does help.
Other causes of grinding your teeth are sleep apnea, abnormal bite or missing or crooked teeth can all cause you to grind your teeth.
Grinding your teeth too often can lead to teeth damage and cause you to have cracked or damaged teeth.