Will We Grow New Teeth Instead of Fillings?
Clinically reviewed by Dr. Abinaash Kaur, DDS, RCDSO, on 2026-08-04. Dr. Kaur is a general dentist in Toronto (Bloor West Village) registered with the Royal College of Dental Surgeons of Ontario.
No, not for the cavity you have right now. A real tooth regrowth drug finished its first human safety trial in Japan, and it's aimed at people born missing teeth, not at teeth that decay took away.
Patients bring me this one on their phones, about once a month now. The headline says Japanese scientists can grow new teeth. Then comes the question underneath it: should I hold off on this filling?
Please don't. I've practised in Bloor West Village for about 25 years, and I've watched a few "dentistry is about to be obsolete" stories arrive and quietly leave. This one is different, because the science is real and it's in people. What the headlines skip is who the drug is for and what the trial was measuring. Both of those change the answer completely.
What is the tooth regrowth drug?
Start with the biology, because it's elegant.
USAG-1 is a protein that acts as a brake on tooth development. It blocks two signals a growing tooth bud needs, BMP and Wnt (Science Advances, Kyoto University group). Take the brake off and more teeth form.
Researchers showed this in mice. Blocking USAG-1, either by knocking out the gene or by giving an antibody against it, "relieves congenital tooth agenesis caused by various genetic abnormalities in mice" (Science Advances). The same paper describes USAG-1 as controlling the number of teeth "by inhibiting development of potential tooth germs" (Science Advances).
That team then built a humanized version of the antibody as its final drug candidate (Journal of Oral Biosciences). The drug is called TRG035, and the company developing it is Toregem BioPharma (Japan Registry of Clinical Trials; Toregem BioPharma).
Here's the mechanism in one sentence, written by the people who built it. The antibody "can potentially rescue the developmentally arrested tooth germ programmed to a certain tooth type" (Journal of Oral Biosciences).
Read that twice, because everything else follows from it. The drug wakes up a tooth bud that's already sitting there, stalled.
Who is it actually for?
People born with teeth missing. That's a real condition with a real name, and it isn't rare.
Congenital tooth agenesis means teeth that never formed at all. The developers describe two targets: hypodontia, five or fewer missing congenital teeth, with a prevalence around 10%, and oligodontia, six or more missing, at about 0.1% (Journal of Oral Biosciences).
In September 2025, Japan's Ministry of Health, Labour and Welfare granted TRG035 orphan drug designation for severe congenital hypodontia (Toregem BioPharma). Orphan designation is a status reserved for rare diseases. It tells you who the regulator expects to be treated.
Most people think this is a future replacement for fillings, crowns and implants. On the evidence that exists today, it isn't. Every published target is a tooth that was supposed to form and never did.
A molar you cracked at 45 didn't leave a spare tooth bud behind for an antibody to find.
What did the human trial measure?
The trial is public, and anybody can read it. It's registered with Japan's national registry as jRCT2051240154 (Japan Registry of Clinical Trials).
Its listed title is "Phase I Single-Administration Study of TRG035 in Healthy Adults," and it's described as a double-blind, randomized, placebo-controlled, dose-escalation study run at Kyoto University Hospital, with a target sample size of 30 (jRCT).
The registered details are worth having in front of you:
- Participants were men aged 30 to 65, each missing one or more molars (jRCT)
- Each got one single intravenous dose, escalating across five steps from 0.4 mg/kg to 24.0 mg/kg (jRCT)
- The primary outcome was safety (jRCT)
- The secondary outcomes were pharmacokinetics and how often the body produced antibodies against the drug (jRCT)
- Anyone with an implant in the molar region was excluded (jRCT)
That's not a criticism, it's how phase 1 works. Phase 1 asks one question: is this safe enough in people to keep going? The registry now lists recruitment status as complete, with the record last updated in October 2025 (jRCT).
One more line from the registry matters. The health condition on file is congenital anodontia (jRCT). The volunteers were healthy adults, and the disease being targeted is still teeth that never formed. Pretty much every headline I've been shown skipped both of those lines.
When could you get it?
Nobody has published a date I can point you to. The registry doesn't give one, and the company's own English site describes planning clinical work without naming a launch year (Toregem BioPharma). Treat any specific year you read as somebody's forecast, not a schedule.
Here's the base rate for context. An analysis of 406,038 clinical trial records covering more than 21,000 compounds found that "13.8% of all drug development programs eventually lead to approval," with roughly two-thirds moving from phase 1 to phase 2 (Biostatistics, via PMC).
A completed phase 1 is genuine progress. It's also the first of several hurdles. After that the drug has to work in the patients it's meant for, clear approval in Japan, then be submitted to and authorized by Health Canada. Your cavity won't wait politely through any of that.
What about the lab-grown tooth in the news?
Different group, different claim, and further from your mouth rather than closer.
A team at King's College London and Imperial College London grew tooth germs in a dish. They built soft gelatin-based gels, tuned the stiffness, and encapsulated dental cells inside (ACS Macro Letters via PMC). One formulation supported "growth kinetics and morphogenesis of tooth germs" (PMC).
Tooth germ is the key phrase. That's the earliest bud of a developing tooth, not something you could chew with.
A 2025 review of the whole field is blunt about where things sit. Pulp and dentine regeneration "has entered clinical trials and demonstrated preliminary efficacy," whole tooth regeneration "has been achieved in animal models but still confronts ethical and functional challenges," and enamel regeneration "remains in its early stages" (Cell Regeneration via PMC).
We've been here before with mail-order aligners: real technology, oversold years ahead of the unglamorous parts. Our post on what happened to SmileDirectClub and Byte is what that looks like when the bill arrives.
Can enamel grow back on its own?
No, and this is the most useful fact in this post.
Enamel is the hard outer shell of the tooth. The cells that build it are called ameloblasts, and they're gone by the time the tooth comes into your mouth. A 2025 review says it plainly: "natural enamel lacks the ability to regenerate due to the absence of ameloblasts" (Tissue Engineering and Regenerative Medicine via PMC).
Bone heals. Skin heals. Enamel doesn't. What gives? The factory shuts down before the tooth erupts and never reopens.
Dentine, the softer layer underneath, is a different story. Your tooth can lay down reparative dentine when it's irritated, which is why a deep cavity handled conservatively can settle instead of needing a root canal (International Endodontic Journal). That same paper is just as clear about the other direction: untreated, "caries will advance through dentine stimulating pulpitis and eventually pulp infection and necrosis" (International Endodontic Journal).
There's promising work on pushing that natural repair further. A King's College London group used clinically approved collagen sponges carrying a small molecule to mobilise stem cells in the pulp and restore dentine (Scientific Reports via PMC). That was published in 2017, and it's still not something I can offer you in the chair.
The window where you can still change the outcome is early, before there's a hole. Our post on whether a cavity can heal itself covers what remineralization can and can't do, and our comparison of hydroxyapatite and fluoride toothpaste covers what to put on your brush.
So what does waiting cost you?
The Canadian Dental Association puts it in one sentence: "If a large cavity is not filled, it can get bigger and cause pain. The tooth may even have to be removed and replaced with a false (or artificial) tooth" (Canadian Dental Association).
Numbers help. Researchers enrolled 565 children and tracked how early lesions behaved over 48 months with yearly bitewing x-rays, with 338 completing every examination (Journal of Dental Research via PMC). The share progressing to a cavity climbed with how bad the spot looked at the start: 19%, 32%, 68% and 66% across four increasing severity scores (Journal of Dental Research via PMC). Molars were the teeth most likely to cavitate (PMC).
So not every early spot becomes a hole, and I won't pretend otherwise. Once a lesion is well established, most of them do.
The staircase in my chair looks like this. A filling stays a filling. A neglected filling becomes a root canal and a crown. A neglected root canal becomes an extraction, and then an implant or a bridge. Every step costs more, takes longer, and hands you back less of your own tooth than the step before. Our crown cost guide shows the gap between step one and step three.
Trading a filling for an implant while you wait on a drug for a different condition is a bad deal.
What has saved Canadians' teeth over the last 15 years?
This is my favourite pair of numbers in a while, and they came out in December 2025.
Statistics Canada measured Canadians' mouths directly between 2022 and 2024, the first direct measurement in more than 15 years (Statistics Canada). Two findings sit right beside each other.
Complete tooth loss among people aged 60 to 79 fell from 22% in 2007-2009 to 8% in 2022-2024 (Statistics Canada). That's from about one senior in five with no natural teeth left, down to fewer than one in ten.
Over the same stretch, decay itself didn't move. Prevalence and severity were "unchanged from 2007-2009," and 93% of adults aged 20 to 79 have at least one permanent tooth affected by decay (Statistics Canada).
Read those two together and you have the whole argument. We didn't cure cavities. We got much better at keeping the tooth anyway, using fillings, root canals, crowns, cleanings and fluoride. Ordinary dentistry saved a generation of teeth while everyone waited for a breakthrough.
The cost of skipping it got measured for the first time too. A score called PUFA counts the advanced consequences of untreated decay: exposed pulp, ulceration, fistula and abscess (Statistics Canada). It affected 22% of adults aged 20 to 79 (Statistics Canada).
More than one adult in five is carrying a tooth that has already gone past the point where a filling would have handled it.
What I'd do if you were in my chair
Have no fear, none of this is an argument for rushing you.
Small early spots get watched and remineralized, not drilled. That isn't me being agreeable, it's how deep decay is managed now, with selective removal and careful handling, because "pulpal recovery occurs even in deep carious lesions" when they're managed well (International Endodontic Journal).
So ask what stage yours is at. "Watch it and recheck in six months" is a legitimate answer, and so is "fill it this week." If you want the questions that separate a real recommendation from a sales pitch, our post on telling a recommendation from an upsell hands them to you.
Some days the schedule pushes me hard, and this conversation still gets its full five minutes. The person who understands why we're filling something is the person who shows up for the next appointment.
If it's been years since your last visit, that's a different conversation and a common one. Our post for people coming back after a long gap was written for exactly that. If you're in pain today, it isn't a waiting question at all, and our emergency guide covers what counts as urgent.
Frequently Asked Questions
Q: Is there a drug that regrows teeth? There's a drug candidate in clinical development, not one you can get. TRG035 is a humanized antibody against a protein called USAG-1, developed for congenital tooth agenesis (Journal of Oral Biosciences). Its phase 1 trial, targeting 30 healthy adult men at Kyoto University Hospital, is listed as complete with safety as the primary outcome (jRCT). No regulator has approved it anywhere.
Q: Will the tooth regrowth drug replace fillings? Nothing published suggests that. The drug targets teeth that never formed, and its developers describe the mechanism as rescuing "the developmentally arrested tooth germ programmed to a certain tooth type" (Journal of Oral Biosciences). A cavity is damage to a tooth that formed normally, and enamel can't regenerate on its own because the cells that make it are gone once a tooth erupts (Tissue Engineering and Regenerative Medicine via PMC).
Q: When will tooth regrowth be available in Canada? No date has been published by the trial registry or the developer (jRCT; Toregem BioPharma). For scale, an analysis of more than 21,000 compounds found 13.8% of drug development programs eventually reach approval (Biostatistics via PMC). Any drug approved in Japan still has to be reviewed and authorized separately by Health Canada before a dentist here could use it.
Q: Can a cavity heal itself if I wait long enough? Damage caught before a hole forms can partly remineralize. Once a lesion has cavitated, it doesn't fill itself back in. In a four-year study that enrolled 565 children, lesions at the two most severe starting scores went on to cavitate 68% and 66% of the time (Journal of Dental Research via PMC). Our post on whether a cavity can heal itself walks through where the line sits.
Q: Can enamel grow back? No. Enamel is built by cells called ameloblasts, and they're gone by the time a tooth is in your mouth, so "natural enamel lacks the ability to regenerate due to the absence of ameloblasts" (Tissue Engineering and Regenerative Medicine via PMC). Dentine, the layer underneath, can lay down a repair layer when it's irritated (International Endodontic Journal).
Q: Scientists grew a tooth in a lab. Doesn't that change everything? Not yet. The King's College London and Imperial College London work produced tooth germs, the earliest bud stage, inside a gel in a dish (ACS Macro Letters via PMC). A 2025 review of the field places whole tooth regeneration in animal models facing "ethical and functional challenges," with enamel regeneration still "in its early stages" (Cell Regeneration via PMC).
Q: What happens if I put off a filling for a year or two? It usually gets more expensive and less conservative. The Canadian Dental Association says an unfilled large cavity "can get bigger and cause pain" and the tooth "may even have to be removed" (Canadian Dental Association). Statistics Canada found 22% of adults aged 20 to 79 already have a tooth showing the advanced consequences of untreated decay (Statistics Canada).
Reviewed by Dr. Abinaash Kaur, B.Sc., DDS (University of Toronto Faculty of Dentistry), who has practised general and family dentistry in Bloor West Village for about 25 years. This article is general oral health information about dental research and tooth decay, not a diagnosis, medical advice, or a substitute for an examination.
Wondering whether that spot on your x-ray needs treating now or watching for six months? That's a fair question and it deserves a straight answer. We're at 750 Annette Street in Bloor West Village, serving the Junction, High Park, and Baby Point. Book an exam with The Village Dentist and we'll tell you what stage it's at, what your choices are, and what happens if you do nothing for now.
