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There are often some headlines claiming how scientists have unlocked the key to growing new teeth in the lab. So what exactly are these lab grown teeth and why are they still not freely available to everyone?

What would be the ultimate achievement, the Holy Grail, the Nobel-Prize winning goal, of dentistry? Very few discoveries would fall into that category, actually, but finding a vaccine for tooth decay would be one. It's an achievement researchers are discovering to be far more complex than initially imagined, however. Another one of these ultimate goals is to be able to regenerate an entire tooth. On the face of it, this seems like something that would be much more difficult to achieve than a vaccine, however some extremely promising strides have been made in this field.

Is Growing Teeth In A Lab Even Possible?

The cue for this direction of research is actually derived from nature itself. Certain animals continue to grow teeth throughout their life spans, demonstrating growing teeth is indeed possible. These animals do not have to worry about losing a few teeth as they use them for hunting, chewing, or burrowing. They just grow them back! 

The sequence of events that lead to a stem cell ultimately turning into a fully fledged tooth is extremely complex with a number of small molecules, genetic signaling and cells playing a role — but the process is now more or less fully understood.

Theoretically, if scientists are able to mimic this sequence of events, they should be able to grow teeth in a lab quite easily. Much like nature has shown it to be possible in rodents, sharks and other animals, humans could regrow teeth from a few cells.

Over the last few years, scientists have been able to grow teeth in controlled settings in mice with predictable success. These bioengineered teeth are grown by mixing together the essential cell populations of two different origins (mesenchymal and ectodermal) and then ensuring that they are provided with the necessary nutrients to form an intial tooth bud. This bud is then implanted inside the rat’s jaws, eventually forming into a complete tooth.

Can We Successfully Grow Human Teeth?

Two approaches are currently being explored when it comes to whole-tooth regeneration. The first is very similar to the approach outlined above. Harvest the necessary stem cells from the body, and then grow the appropriate populations of cells in a lab setting before implanting the tooth germ into the area where you want the teeth to grow.

The other is to implant a scaffold or a biocompatible mesh of the appropriate shape filled with stem cells and then letting it grow into a tooth which will erupt into the oral cavity. This is actually much more difficult to achieve since all the signaling molecules and cells will be regulated by the body. In fact, doctors still have difficulty in regenerating parts of the tooth-bone complex as is attempted by soft and hard tissue grafts during gum surgery or implant placement.

Skeptics cling on to this point and point out that when regenerating individual tissues is still a challenge, it may not be the wisest thing to look at bio-engineering the entire tooth. Sometimes however, starting from scratch is easier than trying to repair defects that have occurred over a period of time.

Growing New Human Teeth: Hurdles That Still Need To Be Overcome

So, Why Are We Not Growing Teeth On Demand Already?       

There are still a lot of challenges that need to be overcome before this dream of growing teeth on demand becomes a reality. Even though scientists now know each and every component that plays a part in the process, they do not know which molecule is required in what quantity and at what time. 

A single mistake in the beginning of the life cycle of the tooth bud can have a huge effect on the final structure that erupts in the mouth. This is proving to be a huge hurdle to overcome.

Another problem is that the stem cells that are needed for the entire process are found in small quantities, most often from the third molars (wisdom teeth), and may have a limited potential to develop into teeth. The next big hurdle is that of time. Normal tooth formation takes around five years. Not everyone would be willing to wait for that long to have their replacement form and erupt. Scientists have to find out a way to reduce this entire process to something more in line with the treatment modalities that exist today. Even an implant placement, for example can frequently take around six to eight months to fully integrate with the body, particularly if grafting is done alongside.

Even if all these problems were to be solved, scientists still do not know what are the triggers needed to dictate the type of teeth that are being formed. All the teeth, from the ones in the front to the chewing ones in the back start out in the same manner and then start to differentiate only in  the later stages of tooth development. This knowledge is essential from the point of dispensing clinical treatment. After all, the end result has to be a tooth of appropriate size and shape to really serve the functions needed.

Why Do We Even Want To Try?

Current methods to replace missing teeth have made tremendous advances in terms of strength, durability and even becoming cost affordable, however none of the treatment modalities are able to integrate with the existing structures. They into co-exist around it, never really becoming a part of the body. This means that the patient does not have the same satisfaction while eating since there are no neural connections. 

A lot of the prosthesis designs are dependent on the strength of the teeth around them and may even involve a sacrifice of healthy unaffected tooth structure.

The challenges that lie ahead of the researchers are many and there more than a couple of people who consider them insurmountable, however there is no douhbt that the goal is worthy of a long and sustained effort. The next time you come across a headline claiming how scientists will be able to grow new teeth in the lab soon, know that while that time has not yet arrived, it is not unthinkable that it will arrive within our life spans. 

Sources & Links

  • 1. Tissue engineering in dentistry.Journal of Dentistry Volume 2, Issue 8, August 2014, Pages 915–928.
  • 2. Tissue engineering and its implications in dentistry. Indian Journal Of Dental Research. Parimala Tyagi. 2009. Vol20, Issue 2, Pg 222-226

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