The ultimate goal in dentistry is to have a method to biologically replace lost teeth; in essence, a cell-based implant rather than a metal one. There has been interesting research on using stem cells to re-grow teeth, and using sharks—which naturally grow new teeth throughout life—as a model for potential re-growth in humans. Humans have the ability to grow a second set of teeth—from baby teeth to the teeth we keep throughout adulthood. Normally it stops there, but it is possible to stimulate the growth of new teeth in adults?

According to one study, it is possible to convert adult dental stem cells into cells that can form teeth. The minimum requirement for a biological replacement is to form the essential components required for a functional tooth, including roots, periodontal ligament, and nerve and blood supplies. Early stage embryos are a source of cells capable of inducing tooth growth. This study showed that embryonic tooth structures in the earliest stages could develop into complete teeth, following transplantation into the adult oral cavity.

There is currently a need to better understand the mechanism of tooth regeneration in an attempt to design more appropriate therapies targeted at human tooth loss. Ultimately, the field of translational dental research aims to uncover what factors govern the transition from a single or restricted set of teeth to the development of multiple generations. A study found that tooth development is highly conserved from sharks to mammals. Scientists have discovered that human beings evolved from a prehistoric shark which existed more than 300 million years ago. According to a new research, a primitive fish named Acanthodes Bronni was the common ancestor of all jawed vertebrates on earth—including humans. A core set of dental genes is utilized by all toothed vertebrates. We share common signaling centers that direct the formation of tooth structures. Sharks retain the capacity for life-long regeneration. Perpetual regeneration of oral teeth has been either lost or highly reduced in many other lineages, including in humans. 

Sharks are uniquely suited for deep comparative analyses of tooth development and regeneration.  The dentitions of sharks are well known for their ability to regenerate in a continuous conveyor-belt manner throughout life. The expression patterns of key members of gene regulatory networks and signaling pathways are important in the development of shark teeth. Re-growth is associated with the lifelong maintenance of a stem cell population. Highly diverse dentitions—in other words from shark teeth to human teeth—utilize the same developmental toolkit. There is a high level of similarity of these core dental genes in vertebrate tooth development. It has been shown that stem-like progenitor cells have the ability to form new tooth generations. This may suggest that slight genetic alterations could be the difference between a limited, mammalian replacement supply and an unlimited dentition as presented here in the shark. This is a promising opportunity for the future of tooth regenerative biology, and sharks could play an important role in the discovery of new methods and key markers for continuous tooth regeneration. Sharks serve as a unique model for the study of tooth regeneration. 

Despite some progress, there remain major obstacles to formulating safe, simple and reproducible cell-based approaches for tooth repair and regeneration that could be used on patients. 

By age 74, twenty-six percent of adults have lost all of their teeth. I am in my early fifties, and I have lost two permanent teeth already. The rest of my teeth are in pretty bad shape—yellowed, chipped and held together by fillings. It has long been a goal of mine to be able to re-grow my teeth—even before I knew it was possible. If a child can grow a second set of teeth, why can’t we grow a third set? I am excited by reading about the research into tooth regeneration—and I hope it pays off in my lifetime. But, if we have the genetic underpinnings for tooth regeneration shared with our shark-like ancestors, can we switch on this power ourselves? Is it possible to turn on the potential hidden ability to re-grow teeth? We do not yet fully understand the mind-body connection and gene expression, but we do know that for some reason certain genes are activated while others lie dormant. I, for one, believe that it may be possible. In a future post, I will discuss the power of goal-setting in coaxing our subconscious mind to work on our behalf.