Squeaky shakes his jaw when he opens his mouth

I am a little concerned about Squeaky - he shakes his jaw when he opens his mouth.  He eats, drinks, plays, sleeps and plays vigorously with his new playmate Bella, but this has come up lately. Is this something to worry about?  If anyone has any answers, let me know - thanks!  

I have no experience with this, but if you're really concerned, definitely ask the vet.