(Credit: kurhan/Shutterstock) Instead of filling our cavity-ridden teeth with putties and cements, a new method that kicks stem cells into action could help teeth repair themselves. Researchers from King's College London implanted collagen sponges soaked with three inhibitor,s including a drug which has been tested as a therapeutic for Alzheimer's, in damaged mouse teeth. Once in place, the drug-infused sponges catalyzed stem cells inside of the dentin — the bony material beneath hard enamel — filling cavities with living tissue and restoring that part of the tooth to health.