Baby teeth contain stem cells that show promise for use in regenerative medicine
Banking teeth requires some planning, and scientists are divided on its utility
Alison Bassetto’s voice is steady and brisk as she explains why her husband’s untimely death prompted her to have her 19-year-old son’s wisdom teeth banked.
The practice of cryopreserving children’s baby or wisdom teeth is one that’s been around for a decade. Tooth banking is not currently popular, but the trend is gaining acceptance mainly in the developed countries, researchers have found.
It’s based on experimental research that suggests stem cells extracted from the pulp of these teeth might someday regrow a lost adult tooth or offer other regenerative medicine benefits – some potentially life-saving.
“So I’ll try not to get emotional here, but my husband was diagnosed with acute myeloid leukemia in 2011,” said Bassetto, of Naperville, Illinois, head of a sales team at a software company.
In 2012, her husband, James, had a stem cell transplant to restore his bone marrow and renew his blood.
“He was very fortunate. He was one of six kids, and his brother was a perfect match,” she said. She noted that her two children, Madeline, 23, and Alex, 19, may not be so lucky if they develop health problems, since they have only each other; the chance of two siblings being a perfect stem cell match is only 25%.
Unfortunately, her husband’s stem cell transplant was not successful. He developed graft-versus-host disease, where his brother’s donated stem cells attacked his own cells, and he died shortly afterward.
However, she says, the transplant had given him a chance at a longer life.
Last year, when her son saw a dentist for wisdom tooth pain, a brochure for dental stem cell storage caught Bassetto’s eye and struck a chord.
“I know stem cells have tremendous health benefits in fighting disease, and there’s a lot ways they’re used today,” she said. “Had my husband had his own cells, potentially, his treatment could have been more successful.”
Medical breakthroughs happen all the time, said Bassetto. “Who knows what potential there is 20 years, 40 years down the road, when my son is an adult or an aging adult?
“Almost like a life insurance policy, is how I viewed it,” she said.
Scientists are divided
Some scientists see storing teeth as a worthwhile investment, but others say it’s a dead end.
“Research is still mostly in the experimental (preclinical) phase,” said Ben Scheven, senior lecturer in oral cell biology in the school of dentistry at the University of Birmingham. Still, he said, “dental stem cells may provide an advantageous cell therapy for repair and regeneration of tissues,” someday becoming the basis for reconstructing bone tissue, retinas and even optic neurons.
Joseph C. Laning, chief technology officer of Provia Laboratories LLC, a stem cell banking company, said the research shows “promise in treating more complex disorders like multiple sclerosis (MS) and traumatic brain injury.”
Dr. Pamela Robey, chief of the craniofacial and skeletal diseases branch of the National Institute of Dental and Craniofacial Research, acknowledges the “promising” studies, but she has a different take on the importance of the cells.
“There are studies with dental pulp cells being used to treat neurological disorders and problems in the eye and other things,” Robey said. The research is based on the idea that these cells “secrete factors that encourage local cells to begin the repair process.”
“The problem is, these studies have really not been that rigorous,” she said, adding that many have been done only in animals and so provide “slim” evidence of benefits. “The science needs a lot more work.”
Robey would know. Her laboratory discovered dental stem cells in 2003.
’Unusual stuff’ within teeth
“My fellows, Songtao Shi and Stan Gronthos, did the work in my lab,” Robey said. “Songtao Shi is a dentist, and basically he observed that, when you get a cavity, you get what’s called ‘reparative dentin.’ In other words, the tooth is trying to protect itself from that cavity, so it makes a little bit of dentin to kind of plug the hole, so to speak.”
Dentin is the innermost hard layer of tooth that lies beneath the enamel. Underneath the dentin is a soft tissue known as pulp, which contains the nerve tissue and blood supply.
Observing dentin perform reparative work, Shi hypothesized that this must mean there’s a stem cell within the tooth that’s able to activate and make dentin. So if you wanted to grow an adult tooth instead of getting an implant, knowing how to make dentin would be the start of the process, explained Robey.
Pursuing this idea, Shi, Gronthos and the team conducted their first study with wisdom teeth. They discovered that pulp cells in these third molars did indeed make dentin, but the cells found in baby teeth, called SHED (stem cells from human exfoliated deciduous teeth), had slightly different properties.
“The SHED cells seem to make not only dentin but also something that is similar to bone,” Robey said. This “dentin osteogenic material” is a little like bone and a little like dentin – “unusual stuff,” she said.
How it works
There is a meticulous process for extracting stem cells from the pulp.
“We very carefully remove any soft tissue that’s adhering to the tooth. We treat it with disinfectant, because the mouth is not really that clean,” Robey said, laughing.
Scientists then use a dental drill to pass the enamel and dentin – “kind of like opening up a clam,” said Robey – to get to the pulp. “We take the pulp out, and we digest it with an enzyme to release the cells from the matrix of the pulp, and then we put the cells into culture and grow them.”
According to Laning, even very small amounts of dental pulp are capable of producing many hundreds of millions of structural stem cells.
Harvesting dental stem cells is not a matter of waiting for the tooth to fall out and then quickly calling your dentist. When a baby tooth falls out, the viability of the pulp is limited if it’s not preserved in the proper solution.
American Academy of Pediatric Dentistry President Dr. Jade Miller explained that “it’s critical that the nerve tissue in that pulp tissue, the nerve supply and blood supply, still remain intact and alive.” Typically, the best baby teeth to harvest are the upper front six or lower front six – incisors and cuspids, he said.
For a child between 5 and 8 years of age, it’s best to extract the tooth when there’s about one-third of the root remaining, Miller said: “It really requires some planning, and so parents need to make this decision early on and be prepared and speak with their pediatric dentist about that.”
Bassetto found the process easy. All it involved was a phone call to the company recommended by her dentist.
“They offer a service where they grow the cells and save those and also keep the pulp of the tooth without growing cells from it,” she said. “I opted for both.” From there, she said, the dentist shipped the extracted teeth overnight in a special package.
Bassetto said she paid less than $2,000 upfront, and now $10 a month for continued storage.
Different than cord blood
So is banking teeth something parents should be doing?
In a policy statement, the American Academy of Pediatric Dentistry “encourages dentists to follow future evidence-based literature in order to educate parents about the collection, storage, viability, and use of dental stem cells with respect to autologous regenerative therapies.”
“Right now, I don’t think it is a logical thing to do. That’s my personal opinion,” said Robey of the National Institute of Dental and Craniofacial Research. As of today, “we don’t have methods for creating a viable tooth. I think they’re coming down the pike, but it’s not around the corner.”
Science also does not yet support using dental pulp stem cells for other purposes.
“That’s not to say that in the future, somebody could come up with a method that would make them very beneficial,” Robey said.
Still, she observed, if science made it possible to grow natural teeth from stem cells and you were in a car accident, for example, and lost your two front teeth, you’d probably be “very happy to give up a third molar to use the cells in the molar to create new teeth.” Third molars are fairly expendable, she said.
Plus, Robey explained, it may not be necessary to bank teeth: Another type of stem cell, known as induced pluripotent stem cells, can be programmed into almost any cell type.
“It’s quite a different story than banking umbilical cord blood, which we do know contains stem cells that re-create blood,” Robey said.
Cord blood stem cells, in particular, can grow to replace diseased bone marrow with healthy cells. More than 80 diseases have been treated with cord blood transplants, according to the National Cord Blood Program.
“So cord blood banking – and now we have a national cord blood bank as opposed to private clinics – so there’s a real rationale for banking cord blood, whereas the rationale for banking baby teeth is far less clear,” Robey said.
And there’s no guarantee that your long-cryopreserved teeth or cells will be viable in the future. Banking teeth requires proper care and oversight on the part of cryopreservation companies, she said. “I think that that’s a big question mark. If you wanted to get your baby teeth back, how would they handle that? How would they take the tooth out of storage and isolate viable cells?”
Provia’s Laning, who has “successfully thawed cells that have been frozen for more than 30 years,” dismissed such ideas.
“Cryopreservation technology is not the problem here,” he said. “Stem cells from bone marrow and other sources have been frozen for future clinical use in transplants for more than 50 years. Similarly, cord blood has a track record of almost 40 years.” The technology for long-term cryopreservation has been refined over the years without any substantial changes, he said.
Despite issues and doubts, Miller, of the pediatric dentistry academy, said parents still need to consider banking baby teeth.
A grandparent, he is making the decision for his own family.
“It’s really at its infancy, much of this research,” he said. “There’s a very strong chance there’s going to be utilization for these stem cells, and they could be life-saving.”
He believes that saving baby teeth could benefit not only his grandchildren but also their older siblings and various other family members if their health goes awry and a stem cell treatment is needed.
“The science is strong enough to show it’s not science fiction,” Miller said. “There’s going to be a significant application, and I want to give my grandkids the opportunity to have those options.”
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Aside from cost, Miller said there are other considerations: “Is this company going to be around in 30, 40 years?” he asked. “That’s not an easy thing to figure out.”
Having taken the leap, Bassetto doesn’t worry.
“In terms of viability, you know, if something were to happen with the company, you could always get what’s stored and move it elsewhere, so I felt I was protected that way,” she said. She feels “pretty confident” with her decision and plans to store her grandchildren’s baby teeth.
Still, she concedes that her circumstances may be rare.
“Not everybody’s going to be touched by some kind of disease where it just hits home,” Bassetto said. “For me, that made it a no-brainer.”