Sasami is right, age shouldn't affect their teeth. The bottom split really sounds a lot more like something related to trauma (getting hit in the face with something or jumping off of something tall and landing on his face). Get him to the vet ASAP because the longer the teeth are out of whack, the harder it is to get them back to "good".
We are as gods to the beasts of the fields. We order the time o' their birth and the time o' their death. Between times, we ha' a duty. - Terry Pratchett.
"Men have forgotten this truth", said the fox, "But you must not forget it. You become responsible, forever, for what you have tamed. - Antoine de Saint-Exupéry