Teeth whitening toothpastes, strips and gizmos are more popular than ever. But what is the evidence that any of them actually work? And what about the HiSmile Teeth Whitening Kit that's been doing the rounds on social media? Are these products The Best Thing Since Sliced Bread or marketing BS? Greg Foot talks to fashion commentator and broadcaster, Grace Woodward about her experience with these products while Professor Martin Ashley, Consultant in Restorative Dentistry at the University Dental Hospital of Manchester, is on hand to separate the science fact from the science fiction. Presenter: Greg Foot Producer: Beth Eastwood