Beyond affecting speech, eating, and social confidence, gum disease bacteria have been linked to heart disease, respiratory infections, and Alzheimer's disease. Ruohola-Baker's team has developed a tooth organoid from stem cells coaxed into becoming enamel- and dentine-producing cells. In the near term, she envisions enamel proteins being painted onto cracked teeth or used in fillings. Ana Angelova Volponi of King's College London is pursuing a similar approach, engineering biomaterials to guide cells into a structured, functional replacement tooth. "It's not very clear, but it's hopeful," Volponi told the BBC.