The best way to judge the quality of a dentist is by his/her thoroughness of the examination. A complete exam is not done to find more work to do, but is a duty of the dentist, on one hand, and something owed to the patient, on the other.
A good exam covers cancer screening, soft tissues, gums, muscles, joints, bite, teeth, old restorations, and aesthetic concerns. It includes photographs and radiographs, sometime even study models. A good exam is followed by a consultation, with time taken to go over with the patients over their concerns, questions, and bring up finding uncovered during the exam. An explanation of the problems found, the consequences of no treatment, the risk and benefits of treatment, and costs involved.
The critical point is found at the end of this consultation appointment; if the dentist gives the patient options, phases of the treatment, and allows for patient input in the decision and speed of the treatment process, chances are the dentist is not only good, but also honest! If the dentist is pushing for fast decisions, scares with dire consequences if not treated, wants to start right now... the best interest of the patient is not coming first!

Michael