How to sue a dentist for failing to fix teeth after five year in braces?

I had my braces from a dental clinic in 2016. My teeth had a slanted angle back then.

The treatment lasted for 5 years, but then the X-ray showed that the roots of my teeth were shortened and the dentist said we have to stop the treatment and remove the braces because of the risk of losing my teeth.

I was very dissatisfied with what happened. I asked what caused the shortening of roots and he did not give me a definite answer. He said probably because I’ve had braces for too long.

So to cut the story short, they removed my braces this June. After 5 years, the angle of my tooth is still bad and slanted. I don’t know what to do. I’m not sure if this is a reasonable post.

But the fact that it took so long for them to fix my teeth and in the end, they were only able to correct the bite.