[Nyororin]

It`s not the problem with Japanese toothpaste - it`s that there is no fluoride in the tap water. Most toothpastes DO have it these days, or at the very least there is no trouble finding ones that do.

My teeth are also absolutely awful because of the lack of fluoride in the water - using fluoride toothpaste didn`t change things a bit. If I`d known about this back before problems arose, I`d have probably gone for fluoride treatments (dentists offer them for quite cheap - around here it`s 1300yen for a treatment once every 6 months to a year)
You can find deodorant these days, but they are tiny and very pricey.

I can`t say I advise bringing a pillow as was suggested, as that is a LOT of space in your luggage for something that you can buy here for less than 1000yen.

Bring a large significant gift for your host family, and a ton of small gifts for everyone else of importance you will meet - teachers, counselors, etc. Not giving a good enough gift is a huge taboo, really. I am STILL complained to by family about the time I had my mother visit and she didn`t bring anything to give to the in-laws. It will reflect badly not only on you, but your entire program and everyone involved.