misaligned jaw?

Question
QUESTION: My 2-year old male rat, Farley, was taking food from me today, and as I was handing him the lab blocks, his jaw seemed to have shifted out of place. It stayed like that for a minute or so and then went back into place. Shortly after, it was back to being out of place. It seems like it will continue to pop in and out of place. What could be the problem and what can I do to help him?

ANSWER: How do his teeth look?

Sometimes malocclusion can do this. Do his teeth look like they are even?

---------- FOLLOW-UP ----------

QUESTION: It's hard to remember what his teeth usually look like, but his bottom incisors may be a tad bit more splayed than usual. Mostly, they look pretty normal to me. It's hard without a point of reference, though. If it is malocclusion, what would be the course of action?

Answer
If it is malocclusion, the vet would need to clip his teeth down and keep an eye on them possibly needing to clip them every month.
It is risky for a rat owner to do it alone because we can accidentally clip the tongue.  Usually the vet knocks the rat out for a minute to clip them good.  
Normally, rats grind their teeth down to a proper length by bruxing and also simply by eating. When teeth are aligned properly they grind down just right to stay at the proper length.  If there is malocclusion, they cannot grind properly and start to grow sideways, sometimes even growing up toward the roof of the mouth causing sores from the teeth rubbing the inside of the mouth.  
They also seem to not be able to eat well either.