Taking bites that are too big to chew can be bad for your jaw and teeth. As is biting into hard candies which can chip teeth. Even apples can cause problems.
If you need to open your mouth more than feels comfortable to take a bite, cut it into smaller portions that are easy to chew.
Also, avoid chewing ice, popcorn kernels and opening nuts with your teeth, which can lead to chipping and breakage of natural teeth and restorations.
And never use your teeth as a tool!