What a lovely story.
You can't imagine how grateful a patient feels when she has a dentist she can trust to give her a good root canal.
I had a root canal years ago that was such a nightmare that I wept -- and ended up writing an essay about why the dentist made it such a terrible experience.
Then, a few years ago I needed another root canal. Needless to say I went to a different dentist and he and his staff were everything that the first dentist had failed to be. The experience was good.
And even though the tooth couldn't be saved and had to be pulled in the end, because he'd warned me that this might be the case, I don't fault him at all and would go back to him in a heartbeat.
When you are in the dentist's char you are at your most vulnerable. It makes all the difference in the world to know that you are in good hands.
I totally understand why your patients would want to celebrate you with mugs.