Just a year ago, Colgate toothpaste seemed to be on the verge of ending the 25-year reign of Crest as the nation`s best-selling dentrifice. But today, executives at Procter & Gamble Co., Crest`s maker ...

Drugstore aisles teem with toothpastes claiming to do everything from fighting plaque or curbing tartar to freshening breath or shielding sensitive teeth. But the most prominent claim – whitening ...