ASK. Ask your consulting doctor (pcp or consultant) if they can recommend someone for second opinion. Do it in a non-threatening way. A good doctor would welcome someone to back them up on what they have told your or to correct them if their opinion is "wrong". There are times when there is just disagreement. Sometimes a 3rd or more opinion is needed.
Second Opinion. In many cases, seeking a second opinion is not only warranted, but necessary. Unless your disease is life threatening and requires emergency care, it is never a bad idea to seek a second opinion. Getting a second opinion helps you feel more confident about your diagnosis and treatment plan. Ask your PCP.
For what? you can get a 2nd opinion for orthodontics by going to orthodontic2ndopinion.com.