I saw this girl recently and we have been waiting for her eye tooth (canine) to pop through. In the meantime the front teeth have been worn down slightly. It shows how important the eye tooth can be in supporting the overall bite. many people think orthodontics is just for cosmetics – I want straight teeth etc. but your teeth are designed to function for chewing. Note how the eye tooth is a big long butress tooth designed to keep the lower jaw from grinding and damaging the other teeth. Without it you can see the wear and chipping in the photos from grinding of the teeth during sleep (bruxism).
This is the same reason I try to convince older adults not to lose the eye tooth if possible because the remaining teeth start to break down. This high stress area often leads to repeated fracture or failure of any replacement tooth such as a bridge or denture.