My wife had a similar experience. Went to a new dentist (A) that had good reviews, high tech facility, etc, said she had 7 cavities. Thought that was a bit odd (and high), so asked friends for recommendations on a second opinion.

Second opinion dentist (B) says she doesn't have any cavities. Wife mentions how dentist A said she had 7 cavities and mentions his name. Turns out dentist B was a professor at Uni and taught dentist A. Dentist B remarked "Dentist A was always an ambitious student".

Wife has had 1 cavity since we switched to Dentist B 15 years ago now. He's been the best dentist we've ever had. The funny part is if dentist A had told her 2 cavities instead of 7 initially, she probably would have stayed with him. But 7? He got too greedy.