Hello,
My RAD start date has been set for 10/28 which is fast approaching and making me really nervous. I have completed my dental work today with a proper cleaning. The fluoride trays should be ready in couple of days and today the dentist prescribed me PreviDent toothpaste.

I am quite confused about the proper way to take care of the teeth throughout and after the treatment. I am very nervous about it as my teeth are not in good shape, I have had ridiculous amount of work done in the past two years. My dental hygiene used to be average, but now I am brushing and flossing 5 times a day, bought the Waterpick, a fancy pricey electric toothbrush, using Biotene mouthwash etc. I had heard a lot of contradictory things and would like to ask you guys for advice on many things.

1. My old dentist mentioned that I should be brushing and flossing every time I after I eat something. My current dentist says that one shouldn't brush more than three times a day, as it might wear off the tooth enamel and hurt the gums. In between, only to use mouthwashes/rinse. Also, he says to use PreviDent all the time (plus the trays), while some other sources claim max twice a day as too much fluoride can be toxic.
2. Flossing -read somewhere that it should be avoided during radiation treatment and one should only use Waterpik. The dentist claims flossing is essential.
3. Mouthwashes - I was using Biotene, but with the newest developments, not sure if I should continue. Also bought Act(with fluoride) for dry mouth and Crest Pro Health alcohol free.
4. Some sources say to avoid snacking/eating between the meals because oft he teeth. Unfortunately I can not eat much at once, and snacking/drinking Ensure was the only way I managed to stop the weight loss - I lost 7lb from 110lb, trying to gain some back, but so far only managed to stop the loss.
5. On the similar note, sugar. I know it is very bad for the teeth and it should be avoided, but it is everywhere, in Ensure, fruit juices etc. And it happens to be really my only vice, I love sweets/carbs and they are pretty much the only thing that might help gain some weight back. Obviously, I am not going to eat sugar candy, but would a piece of chocolate/cookies be that bad if I brushed the teeth immediately? If needed, I will give those up, just trying to figure this whole thing out
Many thanks!

36, female, left tonsil HPV+ SCC, T2N1
8/28/13 SCC in left tonsil
9/12/13 surgery:TORS and selective neck dissection (levels II-IV), 23 nodes removed
9/18/13 post surgery biopsy: 2mm clear margins, a 7mm lymph node positive in level IV, no ECL
10/28/13 rad begins, 30 treatments, tomotherapy
12/09/13 radiation ends!
2/10/14 papillary thyroid cancer
2/26/14 PET shows clear neck other than thyroid cancer, but with high uptake in an ovarian cyst
2/27/14 thyroidectomy
3/5/14 pelvic ultrasound