It is one of the least known health dangers out there, but fluoride and health issues have been a controversial subject for a long time, not least because Hitler tried to utilise it as a potent neurotoxin.
For a really comprehensive analysis of the the dangers associated with fluoride I highly recommend checking out www.mercola.com, Dr Mercola is a world-renowned and highly respected M.d who has challenged the conventional medical world in the USA and specifically argues against some of the dangerous practices of the pharmaceutical world.
Here are some of the issues he has linked with fluoride consumption:
1. Fluoride in your pineal gland may cause cancer
2. Flouride can impair thryoid function (and therefore make you fat, along with a raft of other health complications)
3. It has been linked with neurological impairment
4. Sulfuryl fluoride has been banned in the USA. If you have a strong stomach read this research document http://extoxnet.orst.edu/pips/sulfuryl.htm (thanks to Charles Poliquin's excellent site for publicising this). If normal fluoride has even a fraction of these side effects, I think it is wise to avoid it!
Tom's Of Maine, or Aloe Dent are some of the common brands that do not contain laureth sulphate or fluoride, and on a personal note I have been using them for the past few years with no dental problems whatsoever.