The bubble gum-flavored toothpaste changes from blue to pink after two minutes of toothbrushing. It can be purchased online and at retailers throughout the U.S. for $3.99.

Crest Kids Color Changing Toothpaste and Oral-B color-changing toothbrushes. Image courtesy of Procter & Gamble.

Also, the following toothbrushes can be purchased online and at retail stores:

• The Oral-B Kids Color Changing Manual Toothbrush, which costs $3.99
• The Oral-B Kids Color Changing Battery Powered Toothbrush, which costs $14.99
• The Oral-B Kids Color Changing Electric Toothbrush, which costs $23.99