opening his mouth

[Rhapsody]

I've heard before that a bp constantly opening his mouth might be a sign of infection.

My bp has the perfect conditions, but I have seen him open his mouth before (one time twice in a row). Is there anything else I should look for that would suggest infection? What kind of problem is this?


edit: it's not like it happens everyday/all that often, but i just wanted to know if i could catch it early or if it was something normal bps do sometimes...