He was still a novice meditator. His goal was to become an Arahat, a worthy person. He had given up all his possessions, his family and his friends. He had studied Tripikita night and day and had strove to follow the Noble Eightfold Path, but it was not enough. He had not reached the inner peace, the perfection, the Nirvana necessary to finally become a lama.
Then the toothache came. It would not stop no matter how much he tried to meditate. Yoga failed. He had to visit the dentist who found caries extending down to the root. He would need a root canal operation. He readily agreed. Anything to stop the pain.
The dentist offered Novacaine or Nitrous Oxide. He refused. He had the entire root canal done without any type of anesthesia. And when the operation was finished he knew that he had reached his goal in life.
He was finally able to transcend dental medication.
