Teeth: the workhorse of the human body. Their specialised shapes have meant that humans as a species can eat a broad range of foods, helping expand our population into every territory on Earth. Yet, whereas a shark has thousands of teeth to fall back on should one fall out, we only have two sets; should your adult teeth fall out, you’ll be smiling with a gap.
Indeed, the human body, once the infantile milk teeth are shed, possesses only one other set of teeth which are designed to last a lifetime, with the body incapable of regrowing this structure once lost.
In dentistry, fake teeth are often called upon to fill the gap, implanted into the gum during surgical procedures. However, new research from Harvard University offers a novel technique which may allow humans to regrow the tooth, publishing their report in the scientific journal Science Translational Medicine.
Specialists from various dental medicine and research faculties, as well as engineering and photomedicine experts, all contributed to the findings.
The process involved the use of stem cells and low powered lasers to help regenerate dental tissue, with current methods regrowing teeth in laboratory conditions, explained senior author Professor David J. Mooney during the press release, which are then reinserted into the mouth. He also noted how lasers have already been used in medicine, allowing a lineal trial in humans to be quickly set up. “It would be a substantial advance in the field if we can regenerate teeth rather than replace them,” said Professor Mooney.
The work started using laboratory rats, where holes were drilled in the molars, exposing the tooth pulp, rich in stem cells. Low-dose laser light was then emitted onto the hole, which was then sealed with a temporary cap. The animals were kept healthy and content as the scientists waited to see if the laser triggered any tooth renewal.
Following a three month period, the rodents were examined using high resolution x-rays and microscopy, in order to assess the extent to tooth regrowth following the procedure. They noted that the laser therapy had indeed triggered the formation of a calcified compound known as dentin, which makes up the structure of the tooth.
Further analysis of the molecular process involved in this novel regeneration showed that specific compound, known as transforming growth factor beta-1 (TGF-β1). In normal teeth, this compound remains dormant, so to speak. However, the introduction of laser light caused the production of reactive oxygen species (ROS), the detonator for a suite of reactions and ‘awakening’ the TGF-β1.
As a result, the stem cells are now capable of differentiating into the required structure, in this case dentin. The researchers were excited to see this result, writing in the abstract of the study how their work provided a “mechanistic basis for harnessing resident stem cells with a light-activated endogenous cue for clinical regenerative applications.”
Furthermore, according to the press release, the study helps elucidate previous work using laser technology which only provided inconsistent and sparse results, meaning their study can now be used as a baseline for new work.
“The scientific community is actively exploring a host of approaches to using stem cells for tissue regeneration efforts,” said Wyss Institute Founding Director Don Ingber, who helped fund the research. Ingber also stated that the procedure is “innovative, noninvasive and remarkably simple” and added a “powerful tool to the toolbox”.
The next step in this research is to begin human trials, with the researchers working in close collaboration with National Institute of Dental and Craniofacial Research (NIDCR), which is one of the National Institutes of Health (NIH) in order to write up and draft the require safety parameters and efficacy studies.
What other productive applications would you like to see laser technology used on?