I had veneers done on my two front teeth about 14 years ago. One of them has shifted leaving a gap between my teeth and I can see a spot at the top which looks like the cement possibly? I went to a dentist to have them replaced and they are telling me I have bone loss and cannot get them redone. They want me to get a 6 unit bridge which honestly is terrifying. Is is true that I cannot get them redone if I have some bone loss? I don't know if I should get a second opinion. Thank you.