I have an Alex too!!!
My son Alex is a 28 weeker who will be one in a week and a half - We have a VERY similar story - at around 4 months *actual* he started drooling, fussing, etc... the ped. said that he could be teething..
Well, he is almost a year and has ONE TOOTH!!!! I think the drooling, etc is just a normal phase that all babies go through.. it may or may not be related to teething..
We use a great teether - I think it's by early years - it is small, rubbery and shaped like a triangle and has all these nubby things on it - Alex LOVES it..