The Tooth Fairy is quite a collector with the teeth of hundreds of millions of children in her collection from many years of exercising her craft. When we move on to our permanent teeth however, we are not so keen to part with them and given the option, any of us would give up the "lousy buck" that we were given in exchange for a solid working tooth
. However, since the Tooth Fairy isn't letting go of her collection any time soon, modern science is doing the job on her behalf.
Whether it be as a result of injury, deep cavities or cracks in the tooth itself for some other reason, a damaged tooth is a potential source of infection that dentists currently treat preventatively with endodontic therapy more commonly known as a root canal. While the stereotypically dreaded root canal is not as bad "as advertised", it does have the downside of allowing the tooth to become more brittle over time because the removal of nerves and blood vessels from the tooth during a root canal allows the tooth to lose moisture. To prevent the tooth from breaking, dentists will add a crown to cap the tooth both to hold it together and to seal it as much as possible.
A secondary downside that is more difficult to overcome is that because the tooth "feels no pain", future cavities of the tooth can readily progress to a point where the tooth fails and must be removed. The only protection in this case, in addition to the recommended dental care provided by the dentist, is a regimen of routine check ups to identify cavities early.
When compared to removing the tooth altogether, a root canal is definitely a much better option since it keeps the tooth in place to eliminate migration of the teeth, allows a working tooth for eating and is considered by most to be more appealing. Although the root canal may be the best option currently, it is a bit like adding supports to an old collapsing building rather than rebuilding. Fortunately, some new technologies are pointing toward a better option that may soon be available.
For at least 5 years now, scientists have been using modern industrial design technology in the form of increasingly common three-dimensional printers in order to research bone creation. In the same way that a plastic part can now be printed by building up very thin cross-sections of the part, printing of bone can also be accomplished the same way. The difference is that rather than being made of one material like a plastic part, a bone is made of the hydroxyapatite bone material and living cells so the printer must be able to deposit each type of material and in the correct geometry. The living cells that are deposited are bone marrow stem cells
that convert into bone cells and endothelial cells that form blood vessels.
Now a tooth is not just a piece of solid bone so it cannot be created by "simply" printing a piece of bone
. However, its inner bone-like parts vary mostly by the concentration of minerals, collagen and water where collagen is the common connective tissue found in the body. As a result, by taking into account the "formula" variations at the various locations in the tooth while printing, structures with different characteristics can be built with largely the same materials. With this ability, all but the external enamel of the common tooth could be created. The tooth enamel is a bit special because of its highly crystallized structure.
Once the soft tooth exists, the next required step is to be able to create the tooth enamel to cap the tooth. Researchers have now found the gene that controls the creation of tooth enamel and are now working towards convincing stem cells to become enamel generators. Once these stem cells are properly trained, the concept would be to print the enamel-generating stem cells onto the top and side portions of the soft tooth and then place a properly shaped prebuilt tooth enamel cap on top. The enamel generated by the stem cells would bind with the existing enamel to attach the whole crown to the tooth producing a fully functional tooth.
While none of the techniques that will soon be used to print a new tooth are by any means trivial, they are not extremely difficult either and the tooth is likely to be one of the first complex structures to be created due to its relative simplicity. Whether dental labs will have the resulting technology readily available in house is a good question that depends on how cheap tooth manufacturing equipment can be. In addition, getting a new tooth attached to the jaw will be another challenge given the bacterial juices in our mouths that could inhibit healing, however it is by no means insurmountable.
Since the Tooth Fairy does not seem to be interested in magically providing us new or better teeth, it is good to see that modern science is a bit more helpful. Hopefully in a couple of years, the idea of a root canal will become part of the mythology of years past and will only serve to frighten children who refuse to brush their teeth.Related Links: