You will visit the dentist during week 1 and have a check up, they then book any work needed into your ph1 schedule or send your appointment to ph2. there was a few lads that had fillings done in Raleigh/Sultan and a couple that just had them taken out.
I could only see it being an issue if you had loads of work that needed doing, I heard of a lad that got discharged cause he needed about £4k worth of treatment.
I got made TMU at my medical due to having a hole in my tooth, it was due to unfinished root canal treatment, I went the following week and the tooth broke during the treatment, 6 week wait to get a minor op to get the tooth out, then I had to send in a letter from my dentist saying she was satisfied with everything
I'm sure the font of all knowledge has posted that all dental treatment that needs carrying out, needs carrying out before you get to Raleigh.
Best bet? Don't rely on a load of blokes/gals on the internet.