Which procedure is least effective when dealing with necrotic pulp?

The least effective procedure when dealing with necrotic pulp is electric pulp testing. This method is primarily utilized to assess the vitality of the pulp tissue within a tooth. In cases where the pulp is necrotic, it means the tissue has already died and will not respond to stimuli, making electric pulp testing unreliable. Since the test relies on the vitality of the pulp, a necrotic pulp will yield no response, which does not provide useful information regarding the condition of the tooth.

In contrast, root canal therapy is an effective treatment for necrotic pulp as it involves the removal of the dead pulp tissue, cleaning the root canals, and sealing them to prevent further infection. Patient observation may not be a definitive treatment strategy but can be part of a broader approach to monitor symptoms over time. Finally, a pulp vitality test similarly assesses the condition of the dental pulp, but in the case of necrosis, it would yield a lack of response, similar to electric pulp testing. However, this test can sometimes provide more context in conjunction with other findings, although it won't effectively treat the condition.