I had my tooth pulled at the dentist friday, i wanted to know can i take a excedrin extra strength after i took a 400mg ibuprofen 6hrs ago.

Yes: In fact this may work better for pain management. The ibuprofen you took is mostly out of your system by now.

Yes, but: Be careful to follow package instructions as to dosage. I assume you wish to change analgesics because the ibuprofen is not working as you expected. Extraction was Friday, today is Monday, you should be noticing a lessening of pain by now. If not, return to the dentist or Oral Surgeon who did the extraction for a post-surgical reevaluation.