outer layer of your enamel tooth surface. white, the thing that's really important to dentists is to make sure that that enamel stays strong and resilient for a lifetime the more that we can strengthen and re-harden that tooth surface, the whiter their patients' teeth are going to be. dentists are going to really want to recommend pronamel strong and bright. it helps to strengthen and re-harden the enamel. it also has stain lifting action. it's going to give their patients the protection that they need and the whiter teeth that they want. ♪