This is probably the most misdiagnosis treatment in dentistry. How many teeth have been opened and drained to discover healthy pink tissue? How many needless root canals have been performed? Of course, these have to be followed with a full crown.
Anecdote:
A few years ago, a doctor was working for me on Saturday. A lady six-months pregnant came in with her husband complaining of tooth #14 hurting. Tooth number 15 had a large MO amalgam filling. He took an X-ray but did not see any decay on #14. Next, he tapped the #14 tooth and the woman almost left the chair. He noticed some swelling in the gingival tissue and came to the conclusion the tooth was infected. He told the lady the tooth had irreversible pulpitis and he would have to open the tooth to take her out of pain. Of course, this would be followed with a root canal and crown.
The lady allowed the procedure and left with a hole in her tooth filled with a....