When Dabi Adesoye was growing up in Ibadan, a city of 6 million people in Nigeria, everyone called her “Eji”. In Yoruba, Adesoye’s first language, this translates roughly as “gap teeth”. It might have been a compliment – in Nigeria, a space between the top front incisors is seen as a mark of beauty, Adesoye says – but she hated hers.

“The idea that people were looking at my face and the first thing they would see is this massive gap just made me feel so uncomfortable,” she says from her home in south-east London.

Adesoye, who is 27 and moved to the UK five years ago, had metal braces in her teens, but they were painful and unsightly. She ended up having them removed early. The gap only grew wider. She would clamp her mouth shut for photos, until she did the opposite to make out that she didn’t care. “But, really, I’d absolutely hate the pictures,” she says.

In summer 2020, Adesoye, who works in sales for a finance software company, reached for her laptop to perform what is now an increasingly common search: “adult braces”. She had become aware that orthodontics had changed radically since her childhood. For so long an uncomfortable, food-flecked rite of passage for teens, the “train tracks” of yesterday have become hi-tech, aspirational – and barely visible.

Rather than submit to fixed metal or more camouflaged ceramic braces, adults are lining up to wear snug, clear plastic teeth aligners that achieve the same results. The correction process takes one or two years, requiring a new aligner with a marginally different shape every week or two. After treatment is complete, patients must wear a retainer at night for the rest of their lives to stop their teeth regressing.

Anyone can order aligners online, based on a 3D scan or an at-home mould of their teeth, without even having to look at a dentist’s chair, as the entire examination process takes place remotely. The rise of these disruptive startups has created fissures in a traditionally slow-moving industry, as regulators try to keep up with innovation and consumer demand.

While aligner technology is continually improving, the devices, which should only be removed for teeth brushing and eating, are not new. Invisalign, the biggest manufacturer of aligners, started life in a Stanford University dorm room 25 years ago. But orthodontists report booming demand recently, particularly since the start of the pandemic, as social media and the ubiquity of video calls have thrown up new mirrors in our homes.

“We call it the Zoom boom,” says Anshu Sood, a co-owner of Helix House Orthodontics, a clinic in Nottingham that also provides Invisalign products. Sood is also the director of clinical practice at the British Orthodontic Society, where 84% of members last year reported a pandemic surge in adult patients, mostly aged 26 to 55 (Sood’s oldest patient was a 76-year-old who was sick of her grandchildren laughing at her “Nanny McPhee” smile).

Sood, whose aligner patients typically pay about £4,000, says younger people who were already open to the idea of making aesthetic changes suddenly had the time and cash to achieve them. Young men are increasingly signing up; men now make up almost half of Sood’s patients, compared with about 20% only five years ago.

Jack Castle, 29, a lorry salesman from Nottingham, had never had cosmetic work done, but wanted a perfect smile for his wedding. “Looking back at old pictures, I just can’t imagine getting married with those teeth,” he says.

Then there are the video-callers, says Sood. “They are people in their 30s and older who don’t spend their days looking at their phones and taking selfies, and were not particularly self-conscious. But suddenly they were looking at themselves all day on screen.”

Emma Burnell, 47, had aligner treatment in 2020. “My secret plan was to come out of lockdown with this amazing new smile,” she says. Like Adesoye, Burnell, a political consultant and writer, has bad memories of ineffective teenage braces. (The NHS continues to fund metal braces for under-18s who need them, but not adults, unless they have a medical reason. Teens are increasingly going private for clear aligners.)

“No photos of me smiling existed at all,” Burnell says. She was resigned to a life with crooked teeth, until lockdown – during which she conducted training courses and social gatherings online – turned a niggle into a glaring issue. “Suddenly, I was just seeing my teeth the whole time.”

Adesoye paid £4,000 for her treatment, which involved several appointments with an orthodontist and dozens of aligners over 13 months. “I took painkillers the first day, because there’s quite a lot of pressure, but you do get used to it,” she says. Then she waited, constantly checking mirrors in the hope the gap might begin to close.

Burnell took the more direct route. In the rapidly expanding direct-to-consumer market, patients can have their teeth scanned in a high-street store, or even make their own moulds using a mail-order kit. Computer software then uses the scans or moulds to design the aligners, which are approved remotely by a UK dentist before being made and shipped to customers.

The marketing for these services gives them the feel of a coffee subscription startup. They have huge social media presences and paid partnerships with influencers and celebrities. But their biggest selling point is price. Direct-to-consumer aligners start at about £1,500, paid up front or in monthly instalments.

Burnell went with SmileDirectClub, the biggest player in the direct market. The American company, which was founded by two friends in 2014, arrived in the UK in 2019, when it also floated on the Nasdaq stock exchange with a valuation of more than $8bn. It had revenues last year of $638m and says it has served 1.5 million customers (it won’t say how many are in the UK).

As well as offering a mail-order service with moulds, SmileDirectClub opened “SmileShops” in cities including London, Manchester and Glasgow, where “SmileGuides” scan teeth. “They run this wand over your jaw and mouth and show you these hi-tech pics of your teeth now, then a model of what your tooth journey will be,” says Burnell, who paid just under £1,600 after visiting a London SmileShop. SmileDirectClub says about half of its UK customers use its shops. The other half use the moulds and never see anyone in the flesh.

Some regulators and orthodontist bodies are worried. One issue is a preference among direct-to-consumer providers for using non-X-ray imaging in prescribing aligners [see second footnote]. “Two-thirds of your teeth sit under the gums and when you’re moving a whole tooth you don’t know what you’re bumping into,” says Sood, who considers the prescription of X-rays prudent for the majority of orthodontic patients seeking treatment. Unseen problems can include buried or impacted teeth or cysts, adds the dentist, who says her colleagues are starting to see patients seeking a fix after bad experiences with direct-to-consumer aligners.

According to Sood, tooth decay and gum disease can also be missed – and this has been a growing problem while people have struggled to access NHS dentistry in the pandemic. (Sood says cosmetic dentistry does not affect NHS provision because NHS-funded clinics must still fulfil their contracts.) Without a full examination, including an X-ray, “the implications of moving teeth can be quite catastrophic”, says Sood, including cracked or loosened teeth.

In February, the British Orthodontic Society, a charity that represents orthodontists and is responsible for maintaining standards, published new guidance. It said aligner treatment should only follow a “face-to-face examination by an appropriate orthodontist or dentist” and that a patient must be given the name and contact details of the clinician managing their care. The General Dental Council (GDC), which regulates dentists, also says that, while “a range of interactions between dental professionals and patients” can be provided safely on a remote platform, all of which are currently permitted when supervised by a GDC-registered clinician, “there is no effective substitute for a physical, clinical examination as the foundation” for an assessment of a patient’s oral health.

David Cran, who leads SmileDirectClub in the UK, tells me that SmileShop staff include GDC-registered nurses and that all UK customers are assessed, diagnosed and, where clinically appropriate, treated solely by dentists and orthodontists registered in the UK. The practitioners approve care plans remotely using moulds or images of customers’ teeth before aligners are made. Dentists remain on hand 24 hours a day, seven days a week if problems arise. Cran says SmileDirectClub, which is registered with the Care Quality Commission (this is now an industry requirement), declines to treat complex cases – about 10% of inquiries – and that it has a rating of 4.4 out of five on the reviews site Trustpilot.

“There’s obviously a traditional approach to orthodontics,” says Cran when I put to him Sood’s worries about the potential problems that only a face-to-face check and X-rays can identify. “But the fact that we’re not doing those severe cases and that the imagery we take is so sophisticated means that we’re clearly able to identify underlying issues.”

Not all the concerns are clinical. The startups use social media to market themselves as slick lifestyle brands. But this also brings them into contact with negative posts. In 2020, the New York Times reported that SmileDirectClub had a confidentiality agreement for US customers seeking refunds outside of its refund policy. To receive any money, unhappy customers had first to delete any negative social media posts or reviews – and withdraw any complaints to regulators.

SmileDirectClub says this non-disclosure provision is “customary in both the industry and in general business practices” in the US and is not used in the UK. The company defended its strategy in the US, which has also involved suing regulators. “When we believe that there is an organised campaign to damage our reputation among consumers, dentists and/or investors, we will defend ourselves and our mission to democratise access to care every chance we get,” Susan Greenspon Rammelt, SmileDirectClub’s chief legal officer, told the New York Times. She said that fewer than 5% of customers had received a refund; Cran says the proportion is “much lower” in the UK.

Burnell noticed some movement during her first four sets of aligners, but then they no longer fit her teeth. She complained and a new set arrived after six weeks. She could not fit these either and eventually got a refund. She has paused her search for a new smile. “I should have gone to the dentist, but I was being cheap and trying to cut corners,” she says. (Cran tells me he would happily make contact with Burnell to discuss her experience.)

While some orthodontists have safety concerns about direct-to-consumer aligners, which, of course, are also a potential business threat, many welcome the industry shake-up. “It’s consumers who lead these trends,” says Robbie Hughes, a dentist and the founder of Dental Excellence UK, a clinic in Liverpool. “And it’s clear they want access to something fast with a minimal number of dental appointments at the right cost.”

Like an independent cinema battling Netflix, Hughes, 37, has set out to offer an experience. His clinic, where prices go from about £4,000 for aligners up to £20,000 for a full dental makeover, looks like a luxury hotel spa. His patients have included celebrities such as the Liverpool manager, Jürgen Klopp. “There is this preconception that dentistry is still about old high-street buildings full of anxious patients and bad smells,” he says. “We want to change that.”

Hughes had to extend his opening hours last year to meet the post-pandemic rush. Extreme whitening is also in demand and can be achieved with wafer-thin porcelain veneers. “The trend here and in other cities is to have your teeth done and let other people know you’ve had them done – and that means making them stand out,” Hughes says.

Back in London, Adesoye had her teeth slightly whitened and got a small chip repaired before waiting for the aligners to do their thing. After two months, she began to notice the gap closing. “I’d be in the middle of meetings and I’d just steal moments in the bathroom and look in the mirror and be like: ‘Oh my God, I wanted this for so long and it’s happening,’” she says.

It took 13 months for her two front teeth to be united. “Eji” was no more. She posted a triumphant video to her YouTube channel, Nigerian in London. Her Instagram following shot up from about 1,500 to more than 24,000. “And I don’t think it’s because of my teeth; I think it’s because of my confidence,” she says. “I’ve always tried to make funny videos and it’s only now that I’m comfortable enough to crack jokes.”

Adesoye’s friends and family were stunned. “For the first three months, my mum would video-call me from Nigeria just to see my perfect teeth,” she says. Adesoye is about to get married when we speak. She met Jon, a teacher, before getting aligners. “Now I’m able to say ‘cheeeese’ as hard as I want without feeling self-conscious,” she says, laughing.

• This article was amended on 27 May 2022 to expand on the position of SmileDirectClub. Following publication, representatives of SmileDirectClub contacted us to say that the company assigns UK-registered practitioners to UK-based patients. These practitioners are regulated by the GDC and available 24 hours a day, seven days a week throughout treatment.

• This article was further amended on 1 June 2022 to clarify SmileDirectClub’s position on X-rays. SmileDirectClub says that a 3D scan can often eliminate the need for X-rays. And, although the company believes X-rays can be harmful, and numerous studies show that they are not clinically necessary in all cases, SmileDirectClub’s practitioners can (and do) request that patients obtain X-rays if they deem them necessary to determine whether the patients are candidates for clear aligner therapy.