Researchers have announced a discovery that could transform the future of dentistry: the identification of two types of stem cells capable of naturally regenerating teeth and bones. The work, published in the scientific journal Nature Communicationsshows how these cells develop and communicate to rebuild both the tooth roots and the bone that supports them in the jaw – the so-called alveolar bone.
The research was led by Professor Wanida Ono, from the University of California at San Francisco (UCSF), and Mizuki Nagata, from the Institute of Science Tokyo, with the collaboration of teams from the University of Texas, the University of Michigan, Kyushu University, in Japan, and the University of Gothenburg, in Sweden. The group specializes in dental biology and bone regeneration and has been studying, for more than a decade, the genes and mechanisms that control the formation and repair of tissues in the mouth.
In experiments carried out with genetically modified mice, scientists were able to monitor the behavior of stem cells during the growth of tooth roots and the bone around them. The study identified two main cell lineages: CXCL12+ cells, located at the tip of the root, and dental follicle cells, which form the alveolar bone.
CXCL12+ cells, also called apical papilla cells, were shown to be essential for producing dentin – the hard tissue that forms the inside of the tooth – and cementum, which covers the root. According to researchers, these cells are activated by a molecule called Wnt, which works as a “biological switch” capable of stimulating growth and natural regeneration. When the tooth suffers an injury, this same group of cells has demonstrated the ability to help rebuild alveolar bone, which indicates a high potential for the development of regenerative therapies in the future.
The second set of cells observed, located in the dental follicle, acts directly in the formation of the bone that supports the teeth. The study revealed that this process is controlled by a genetic mechanism called the Hedgehog–Foxf axis, which needs to be temporarily deactivated for the cells to transform into osteoblasts, responsible for creating bone tissue. When the Hedgehog signal remains active for too long, the regeneration process is blocked and bone does not form correctly.
The authors explained that the secret to regeneration lies in the balance between activating and silencing certain genetic signals within cells.
“We discovered that precise control of these pathways is essential for the bone around the teeth to form and remain healthy,” they stated in the research. “It is a unique biological mechanism, specific to teeth, which depends on an exact sequence of molecular connections and disconnections”, they add.
The alveolar bone is a vital structure: it holds the teeth fixed and absorbs the pressure of chewing. However, this tissue is one of the most affected by oral diseases, especially periodontitis, which causes bone loss and, according to research, affects around 3.5 billion people worldwide. To date, there is no treatment that can completely regenerate this bone.
With the discoveries of the group led by Ono and Nagata, scientists believe it will be possible to develop treatments capable of activating the patient’s own stem cells to restore damaged teeth and bones. In the long term, the goal is to create therapies that eliminate the use of prosthetics or titanium implants, replacing them with biological methods based on natural regeneration.
“These cells function as small reconstruction factories within the body,” explained the researchers. “Now that we know which signals control their function, we can think of ways to use them to restore missing teeth and repair damaged bones.”
