I had a lesson to tell too.
I had a officemate whose husband just graduated from dental school for two years and just bought a clinic at that time. She told me that I don't need to pay co-pay if I go to her husband's dental clinic and he will take care of me very well.
However, I had really bad experience there. He reparied my two front teeth really badly. It was so obvious that there were two new patches on the teeth. I was so humiliated about the repair. I went to another dentist to fix this. The new dentist told me what he did was totally wrong.
Since he is my officemate's husband, I did not sue him.
My lession is: Never use people you are familar with. Never use a dentist that has less than five year's experience.