Most physicians and dentists believe that they are good at what they do.. A very old article (2004) appeared in the New Yorker Magazine about the differences in medical care and medical outcomes.
This is the article: https://www.newyorker.com/magazine/2004/12/06/the-bell-curve
Doctors themselves were shocked to learn that some hospitals have significantly better outcomes than other hospitals.
How can this be???
Human nature. Every physician and dentist firmly believes that they are better than average until they are confronted with the results of their own outcomes.
This is why it is soooo important to be evaluated and treated by the best.