A false-negative response to the pulp tester may occur
Responses Obtained from Electric Pulp Testing
False-Positive Responses
Partial pulp necrosis
Patient’s high anxiety
Ineffective tooth isolation
Contact with metal restorations
False-Negative Responses
Calcific obliterations in the root canals
Recently traumatized teeth
Immature apex
Drugs that increase patient’s threshold for pain
Poor contact of pulp tester to tooth
Cohen's Pathway of the Pulp ed: 11th Pg18
primarily in anterior teeth.
in a patient heavily premedicated  with analgesics, narcotics,  alcohol,  or tranquilizers.
most often in  teenagers.
in the  presence of periodontal  disease.