Dental visit/cavity filling questions?

Ok, my teeth are jacked up, no better way to put it. Parents NEVER took me to a dentist, now that I am an adult, I am trying to get everything taken care of fast. I have about 8 cavities that need filling, then I will have some type of straightening device put on then whitening. I want to speed up the process so I can get the straightening over with. Why won't/can't dentists do all the cavitiy fillings in one appointment/day/sitting? Is there a procedural or medical reason they can't/won't do them all at once?
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I would guess that it has more to do with scheduling than anything else. if he were to do all 8 fillings at one sitting, you are talking about a significant chunk of time. Dentists normally shedule their time in 15 minute chunks. Finding that big a chunk could be impossible. There could be other reasons, but this is my guess. hope if helps. Good luck!!
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