I was told I need root canals and crowns on my front 6 teeth, and they absolutely have to be done in one 3 hour appointment for 23,500. When I told my dentist I couldn't afford all that at once and asked if I could just do a few teeth to start with and go along as I could afford the rest of the treatment - he was adamant that that won't work and I need them done all at one time. Should I get a second opinion? Or will most other dentists say I need them all done at the same time as well?