Front Tooth is Uneven? (photo)

When I was about 10 I fell and chipped a tiny piece of my front tooth. The dentist shaved it a little bit and told me that he would shave the other tooth when I got older so that it would look like nothing ever happened. I am 20 now. My teeth are straight, but now that I am older I have noticed that the front tooth that was shaved is now longer than the other front tooth that was never touched. What could be the cause of this? Can the dentist shave it to make them both even?