Tooth paste is "whitening" due to abrasives added to it.  It whitens by
rubbing off stains.  It does not change the intrinsic color of the tooth.
ADA approval is voluntary and not required.  P&G must have decided that they
are selling enough of the product to not bother with ADA approval.  ADA
approval used to very important to me.  Today, I get a lot less excited
about it.  Last time I heard, toothpaste was considered a cosmetic rather
than a drug, so government testing of the product is not the same as testing
for cough medicine.  Over time, "whitening" toothpaste (since it is more
abrasive) would wear off more enamel than other toothpastes.  How much is
debatable.  I do NOT suggest my patients use "whitening" toothpaste for
extended lengths of time.  Keep brushing 2-3 times a day.  Brush for at
least two minutes each time.  Use a Major Name Brand toothpaste that have a
reputation to uphold rather than some no-name brand which have nothing to
lose if the product is not what they claim it is.  Remember that the FDA
does not check it that extensively unless the manufacturer makes a specific
claim in their advertising.

I figured that it had something to do with how long it takes to get ada
certification. I found the following on the crest website:

The following Crest versions contain the ADA Seal:
Crest Cavity Protection
Kids Crest
Crest Tartar Protection
Crest Sensitivity Protection
Crest MultiCare
Crest Extra Whitening
Crest MultiCare Whitening

Although we don't have the ADA Seal of Acceptance approval yet for
Baking Soda & Peroxide Whitening, Advanced Cleaning, Dual Action
Whitening, Crest Plus Scope, Rejuvenating effects or Whitening
Expressions versions, all Crest toothpastes contain the same clinically
proven anti-cavity ingredient -- fluoride. It may also help to know the
process to apply for the ADA seal can take several months--even years--
to receive.

I recommend Crest for my patients who are not sensitive to sodium
laurel sulfate.

Dave Leader, DMD
Malden, Ma