OK Mommies and Daddies...we need some advice

For the first 6 months of his life, Landon was a great sleeper, especially at night. I could put him to bed at 8 p.m. and not hear a peep from him until 6 a.m.

Ever since his top two teeth came in, his sleeping habits are hit or miss. Some nights we get a full night's sleep, and other nights he wakes up around midnight screaming. (Not just a fuss or a cry - a full-fledged exorcist-type scream.)

Before bed, Landon gets about a half to three-quarters of a jar of baby food, then nurses until he gets drowsy, at which point we move him into the crib. The nights that he is waking up, he is waking up and acting like he hasn't seen food in years. Case in point, last night. He ate his food, nursed a while and fell asleep in his crib. At 11:30 he woke up screaming like a banshee. I tried walking with him,  rocking him, cuddling him, giving him his binky, laying him in his Pack n Play where he could see me and I could lean over him so he felt like he was being held. I tried distracting him for nearly 45 minutes and no dice. Finally, Brian and I broke down and gave him a bottle. The little pig devoured 7 ounces. Normally, during the day he only drinks about 4-5 ounces at a time, so 7 ounces isn't insignificant.

Any ideas on what could be waking the baby, or what we can do to make sure he's completely full before he falls asleep? We still have good nights when he makes it through without waking up and needing fed, but as I'm sure all the parents out there can appreciate, this is getting old really fast. I've tried letting him cry himself to sleep, I've tried walking in his room so he can see he's not alone. I've tried walking in after he's cried a few minutes, talking to him and rubbing his back (and maybe picking him up if he's really upset) then walking out for a while and repeating, but staying out for a little longer each time. Nothing works but food. But the kid can't possibly be so hungry that he can't sleep - according to friends, doctors and books, we're well past the stage where he *needs* food at night.

We're getting to the end of our rope, so I'm up for any suggestions or ideas. Thanks in advance!