When people are asked about what they think damages teeth, they will probably mention sugar. They would be right, but that's not the only problem. You might be surprised to know that acidic things like orange juice can also damage the enamel on your teeth, too. You don't have to avoid these things, but you should limit contact with your teeth and brush your teeth afterward.
Other types of tooth-damaging habits include crunching up ice, chewing on pens, sucking your thumb, and related types of behaviors. Food should be easy to eat, and you should never put anything in your mouth that's not safe, like sharp objects, pens or pencils, and random items to chew on. Those things can really damage your oral health and harm your teeth.