I would say most definitive answer would be provided by dentist or TMJ specialist. They would need to do oral exam + possibly x-rays.
They may also ask questions like...
Does your jaw pop, crack, make any type of sound? Do you experience any pain in the jaw? Does it radiate to your shoulder, head, ear, arm? Do you ever wake up from feeling tightness around your teeth/ Do you ever wake up from clenching teeth?
Clenching teeth usually has effect on teeth as well. Clenching, bruxism (grinding) leads to making top of your teeth looking smooth.
(Like that - http://0.tqn.com/d/dentistry/1/0/f/2/bruxism.jpg)
Abscess is also possibility, again they would have to do exam/x-rays.
Hmm, you can try messaging Scottma to ask more about TMJD.
All in all, I would suggest for you to schedule appointment with a dentist to get it checked. :)