The reputation belongs to the nineteen-seventies. Under magnification, with modern anaesthesia and rotary instrumentation, it is one of the quieter appointments we do.
Why it used to hurt
Inflamed pulp tissue is genuinely difficult to anaesthetise with a single standard injection, and for decades that was the only technique available. Supplementary intraligamentary and intraosseous techniques solved it. Profound anaesthesia is now the expectation, not the hope.
What the microscope changed
Most root canal failures were missed anatomy: a fourth canal in an upper molar, an isthmus between two canals, a lateral branch near the apex. At twenty times magnification those are visible rather than inferred, and success rates moved accordingly.
Afterwards
Expect tenderness to biting for two or three days as the ligament settles, managed with ordinary analgesics. The tooth then needs a cusp-covering restoration, because an endodontically treated molar that is left with a plain filling fractures far more often than one that is properly protected.
