There are two considerations to keep in mind when buying a toothpaste: clinical effectiveness and aesthetic appeal. On the former, I talked to dentists on both sides of the Atlantic. On the latter, I and a team of researchers (my friends, mostly) sampled more than 35 different toothpastes. First, the clinical categories.
Fluoride: Clinical effectiveness basically means "Does it have fluoride?" If it does, it's effective--fluoride strengthens tooth enamel. Some toothpastes boast
Tartar control: For real! Tartar control toothpastes (Crest Tartar Control, Colgate Tartar Control With Micro-Cleaning Crystals) feature an ingredient called tetrasodium pyrophosphate. This sponges up minerals in your saliva that would otherwise collect on your teeth and form tartar (hardened plaque). Tartar control toothpastes can't remove tartar, but they can stave it off.
Toothpastes for sensitive teeth: For real--sort of. Toothpastes for sensitive teeth (Sensodyne, Crest Sensitivity Protection) use potassium nitrate to block nerves connected to your teeth. This works for people with receded gums. But if your sensitivity stems instead from cavities, habitual tooth grinding, or a root canal problem (as it does for most people), sorry--these products won't do a thing for you.
Baking soda: Bogus! Baking soda (Aquafresh Baking Soda, Colgate Baking Soda & Peroxide) is a popular toothpaste ingredient. Baking soda does nothing whatsoever for your teeth. However, its effervescence may leave your mouth feeling fresh and clean. If this encourages you to brush more often, mazel tov.
Whitening: Entirely bogus! Whitening toothpastes (Mentadent Advanced Whitening, Colgate Platinum Whitening, Rembrandt, countless others) remove surface stains--but all toothpastes will do this, even the nonwhitening kinds. No toothpaste can whiten your teeth permanently. Dentists can apply peroxide solutions to bleach your teeth (just as peroxide would bleach your hair), but the peroxide would have to stay on your teeth for several continuous hours before it made any difference. Brushing with whitening toothpastes does nothing, no matter how many times you have at it. Topol "smoker's" toothpaste claims to remove stains caused by smoking. Again, it is no more effective than any regular toothpaste would be--it just costs more. Rembrandt's whitening pastes can cost up to $8 per tube--a horrible rip-off.
Triclosan: For real! Triclosan is an anti-microbial solution currently available in a single toothpaste: Colgate Total. One dentist I spoke with called Total "the first revolutionary toothpaste in a long time." Why? Triclosan clings to your teeth even after you finish brushing and continues to kill bacteria (the dentist says you may feel a "residual slipperiness" after you brush with Total). Because it alone contains triclosan, Colgate Total is without question the most clinically effective toothpaste on the market, for now. Other toothpastes will no doubt add triclosan soon.
Of course, as noted above, any fluoride toothpaste will do an adequate job. For this reason, you may wish to buy CVS brand tartar control toothpaste (or a similar generic brand), which is fluoridated, has tartar control, and is every bit as effective as every other toothpaste save Colgate Total, yet costs significantly less than its flashier competitors. Or you may wish to ignore all the above advice and choose among the flashier competitors for aesthetic reasons, which are laid out below.
Consistency: This is determined foremost by whether the toothpaste is a "gel" or a "paste." Gels use silica as an abrasive to help polish teeth. Pastes use calcium carbonate to the same end. Simply a matter of preference for the brusher. For some reason nearly every kids' toothpaste (Colgate Barney, Oral-B Rugrats) is a viscous gel--especially perplexing since thick gels are ineradicable when smeared across a sink top. Consistency has a direct impact on ...
Ease of squeeze: Some brands offer smooth, even flow from the tube; others do not. Crest is the standard here, while Colgate products tend toward runniness. The outlier: Rembrandt Age Defying Adult Formula Toothpaste (don't ask about the "Age Defying" part). This product was so thick that it refused to come out of its tube, even when squeezed with both hands at once. My researchers quickly dubbed it "the sword in the stone." Only stomping on the tube with a shod foot produced any results, and those meager. One shudders to imagine an actual aged person attempting to use this toothpaste.