A recent study published on May 28, 2014 in the journal Science Translational Medicine has revealed that it might be possible to use low-level laser light to re-grow teeth in rat subjects. The study was published by a team of Harvard scientists led by David J. Mooney, the Robert P. Pinkas Family Professor of Bioengineering at the Harvard School of Engineering and Applied Sciences (SEAS).
“Our treatment modality does not introduce anything new to the body, and lasers are routinely used in medicine and dentistry, so the barriers to clinical translation are low,” said Mooney, in a press release issued by the Harvard School of Engineering and Applied Sciences. “It would be a substantial advance in the field if we can regenerate teeth rather than replace them.”
The team used a low-power light to trigger stem cell differentiation to form dentin in rat subjects. The procedure was developed and carried out by lead author Dr. Praveen Arany. Dr. Arany drilled holes in rat molars, used a low-powered laser to illuminate tooth pulp that contains dental stem cells, and applied temporary caps to cover the holes. After 12 weeks, x-rays revealed that the procedure had triggered dentin formation.
Dentin is a hard, dense tissue that forms the bulk of a tooth beneath the enamel. “
It was definitely my first time doing rodent dentistry,” said Arany in the same press release. “This is one of those rare cases where it would be easier to do this work on a human.”
Important to note is that the newly formed dentin was almost identical to regular dentin, with a few morphological differences.
The Mooney team discovered that a regulatory protein called “Transforming Growth Factor Beta-1 (TGF β-1)” is responsible for triggering dental stem cell growth. The low-level laser triggered reactive oxygen species (ROS) to activate latent TGF β-1 that eventually triggered dentin formation.
“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 in the same press release, “Dave and his team have added an innovative, non-invasive and remarkably simple but powerful tool to the toolbox.”
Stem cell differentiation is normally difficult to accomplish, requiring a complicated process that involves removing stem cells, triggering differentiation externally, and inserting them back into the desired somatic location. The Mooney team’s research is an important step forward both for regenerative medicine and stem cell research in general.
The Mooney team’s research also sheds light on Low-Level Light Therapy (LLLT), a previously anecdotal scientific hypothesis that was said to be able to do everything from rejuvenating skin to stimulating hair growth. Also known as photobiomodulation, LLLT research has been accruing valid scientific footing since the dawn of the medical use of lasers in the late 1960s. This new study is the first time that LLLT has been successful at the molecular level.
Dr. Arany’s aim is to move onto human clinical trials. “We are also excited about expanding [the study’s observations] to other regenerative applications with other types of stem cells,” he said.
The research was a wide-scale joint collaboration between institutions including the Wyss Institute for Biologically Inspired Engineering at Harvard, Harvard SEAS, Harvard School of Dental Medicine, Harvard-MIT Division of Health Science and Technology, New York University School of Medicine, and Boston Children’s Hospital. Dr. Mooney is also a Core Faculty Member at the Wyss Institute.