Dental: do i tell the present dentist that i want to get a second opinion on his treatment plan when i suspect he will be extremely mad at me?

Not at all. : I actually encourage patients to get a second opinion if the have any doubts or questions about my methodology or treatment plan. There are many different "ways to skin a cat," and I never take it personally. However I usually find that those who go and get a second opinion usually come back and are much more eager and comfortable with moving forward with treatment. Just my two cents though.

Non Issue: There is no reason your present dentist should be mad at you for wanting to confirm a treatment plan. If you are really that concerned about offending them, get the second opinion without mentioning anything. You will need radiographs, and that may necessitate taking another set.

Yes: You dentist will mind more if you get a second opinion and don't tell him. Doctors should encourage second opinions. If you doc is bothered by a second opinion, you don't want him treating you. Your right as a patient.