How should I treat my adult dogs loose front tooth?

I have an older lab, his teeth were never strait and I always a small concern. I just noticed that one of his bottom front teeth is super loose. I haven't messed with it for fear that it may expose a nerve. What should I look for and how should I have the problem taken care of?Note: I am a struggling college student who is low on money, I will go to the vet but only if there isn't another option. I appreciate any advice!

give the dog a bone its probaly just baby teeth