People with missing teeth can grow new ones, say Japanese dentists who are testing a drug they hope will provide an alternative to dental implants.
Unlike reptiles and fish, which tend to replace their teeth regularly, it is widely accepted that humans and most other mammals grow only two sets of teeth.
But hidden beneath our names are the sleeping buds of the third generation, according to Katsu Takahashi, head of oral surgery at the Medical Research Institute Kitano Hospital in Osaka.
His team began clinical trials at Kyoto University Hospital in October, giving an experimental drug to adult test subjects that they say has the potential to trigger the growth of these hidden teeth.
The technology is “completely new” to the world, Takahashi told AFP.
Prosthetic implants used for teeth lost to decay, disease or injury are often considered expensive and invasive.
So “natural tooth restoration definitely has advantages,” said Takahashi, the project’s lead researcher.
Experiments on mice and ferrets show that blocking a protein called USAG-1 can activate a third set, and researchers have published photos of the labs of the animals’ teeth.
In a study published last year, the team said “their antibody therapy in mice is effective in developing teeth and could be a breakthrough in treating dental anomalies in humans”.
– ‘Only the beginning’ –
Currently, dentists are prioritizing the “difficult” needs of patients with six or more permanent teeth missing from birth.
The hereditary condition is said to affect about 0.1 percent of the population, they can have severe chewing problems, and Japanese people often spend most of their teenage years wearing a mask to hide large gaps in their mouths, Takahashi said.
“This drug can be a game changer for them,” he added.
The drug is therefore mainly aimed at children, and researchers want it to be available as early as 2030.
Angray Kang, a professor of dentistry at Queen Mary University of London, knows of only one team pursuing the same goal of using antibodies to grow or repair teeth.
“I would say that Takahashi’s group is leading the way,” the immunotechnology expert, unaffiliated with the Japanese research, told AFP.
Takahashi’s work is “exciting and worth pursuing”, Kang said, in part because an antiviral drug that targets a protein similar to USAG-1 is already being used to treat osteoporosis.
“The race to improve one’s teeth is not a short sprint, but rather a comparable set of back-to-back consecutive end-marathons,” he said.
“This is just the beginning.”
Chengfei Zhang, a clinical professor in endodontics at the University of Hong Kong, said that Takahashi’s method is “innovative and holds an opportunity”.
“The idea that people with normal teeth can produce a third of their teeth is revolutionary and controversial,” he told AFP.
He also warned that “what comes out of animals does not always translate directly to humans”.
The results of the animal experiments raise “questions about whether artificial teeth can be functional and aesthetically pleasing to replace missing teeth”, Zhang added.
– ‘On the Moon’ –
Takahashi confidently states that the position of the new tooth in the mouth can be controlled, if not marked, by the injection site of the drug.
And if it grows in the wrong place, it can be moved through orthodontics or transplantation, he said.
No young patients with congenital disease are participating in the first clinical trials, since the main goal is to test the safety of the drug, rather than its effectiveness.
So now, the participants are healthy adults who have lost at least one tooth.
And although tooth restoration is not the goal of the trial at this time, there is a small chance that could happen to such subjects, Takahashi said.
If so, the researchers will have confirmed that this drug can work for those with tooth loss – it would be a medical victory.
“I would be over the moon if that happened,” Takahashi said.
This may be particularly welcome news in Japan, which has the second-largest population in the world.
Health ministry data shows more than 90 percent of people aged 75 or older in Japan have at least one missing tooth.
“The hope is great that our technology can directly improve their healthy lives,” said Takahashi.
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