Adults cannot grow new teeth naturally. However, scientists have found a way to combine cells from adult human gums and cells from the molars of fetal mice to create bioengineered teeth.
As of March 2012, bioengeered teeth were still quite a way from being ready for clinical use, according to research that was published in the Journal of Dental Research. It does mean that science has taken a positive step towards growing teeth to replace those that have been lost. The cells from the embryonic mouse induced tooth-producing signals from the adult human gum tissue, making them a realistic choice for clinical applications in replacing teeth.
More recent work in this field in China showed successful tooth growth using stem cells that come from urine. This method is less controversial than using human embryos. These tooth-like structures were placed in mice. They contained dentin, dental pulp, enamel organ and enamel space. Though it's promising, as of 2014, there is no proven way for adults to grow teeth.