Q. Pain - criteria for endosteal implants?

Pain and tenderness are subjective criteria and depend on patient's  interpretation of the degree of discomfort. Pain is defined as unpleasant sensation from mild discomfort to excruciating agony. Tenderness is more of an unpleasant awareness of the region. Once the implant has achieved primary healing, absence of pain under vertical or horizontal forces is the primary subjective criteria. Percussion and forces upto 500g (1.2lb) are clinically used to evaluate implant pain or discomfort. Pain does not occur unless the implant is mobile and surrounded by inflamed tissue or has rigid fixation but impinges on the nerve. The presence of pain requires removal of the implant, even in the absence of mobility. Pain from rigid fixated implants is expressed as an early problem, whereas pain from mobile implant may occur early or late in the treatment. In either case the condition rarely improves.

Implant sensitivity or mild tenderness rather than pain in a rigid implant is most unusual and signals more a complication for an implant than for a tooth. Tenderness during function or percussion usually implies healing in the proximity of a nerve or on rare occasion bone stress beyond physiologic limit. If implant tenderness immediately postsurgery occurs in the proximity of the mandibular canal the implant may be unthreaded 1 mm and re evaluated for a decrease in symptoms after 3 or more weeks. If the tenderness is after stage 1 healing and is not due to surgical encroachment on an anatomical landmark stress may be the causative factor. Treatment then consists of elimination of as much stress on implant and or prosthesis (If immediate loading) as is possible for 3 or more weeks.