I have a 40 year old male patient. Three weeks ago, I removed an implant from the 3rd quadrant in the canine area and on the same day placed a NobelActive implant in each of his mandibular lateral incisor sites. I achieved a primary stability of over 45Ncm. I placed cover screws and closed both implants with a flap leaving nothing exposed. Three weeks later the patient still has 4 out of 10 level pain on the pain scale which was reduced from an 8 out of 10 on the day of surgery. The patient still has to take analgesics. There was no evidence of infection, exudate or purulence. What could be the cause of this continued pain?