A Belfast tooth-whitening clinic whose previous owner was convicted for using carcinogenic gel has refused to confirm that it no longer uses the banned substance.
The HD Smile Clinic on the Shankill Road has also refused to confirm if any of its staff are legally permitted to apply the product it promises will lift colour by eight shades in just one session.
"The public will make their own decision if they want to use our service, or go to their dentist," a spokesperson for the business said in response to a series of key questions.
The company was dissolved in 2017 under the ownership of Samuel Irvine Madine, who escaped jail earlier this week.
The former director was handed a 12-month probation order for the use and supply of "carcinogenic" tooth-whitening products after pleading guilty to five charges when a case was brought by Belfast City Council, following a complaint made in April 2015.
As tooth whitening falls within the practice of dentistry, it can only be carried out by individuals regulated by the General Dentist Council (GDC) such as dentists and dental therapists.
But because The HD Smile Clinic refused to reveal the identity of any of its technicians, the Belfast Telegraph was unable to confirm if they are operating legally.
A previous search by the council's Environmental Health Department which led to Madine's conviction found four products which contained sodium perborate - a substance which is banned across Europe due to its cancer-causing properties.
Testing also found all products to contain levels of hydrogen peroxide in excess of the permitted level of 0.1%.
One product was found to contain more than 300 times the legal limit, breaching the Cosmetic Product Enforcement Regulations 2013.
The HD Smile Clinic is currently offering "sodium-based" laser teeth whitening with "instant results" for £49, and a technician there told this newspaper the whitening agent works wonders.
"You are guaranteed eight shades whiter," they said.
"It will last six to nine months and then you come back for a top-up.
"It only takes one or two sessions to get to your maximum whiteness."
When asked about the clinic's reputation, he then falsely claimed that Madine was operating from premises across the road in 2015 and that a picture of The HD Smile Clinic was wrongly used in recent negative media reports.
"It wasn't actually us," the employee said.
"That owner isn't connected to us in any way."
The company refused to confirm the name or provide contact details of its current owner - they said she is currently "sunning herself in the Maldives" and therefore unavailable to comment and threatened legal action.
The spokesperson for the company then refused to provide contact details for any legal team.
The Belfast Telegraph is aware of one dental surgery in Belfast which stopped offering HD whitening due to the legal restrictions.
"We found it's just not possible to obtain HD with the permitted amounts of hydrogen peroxide," a member of staff explained.
"To significantly lift the shade of someone's teeth would take multiple sessions over several weeks."
A Belfast City Council spokesperson confirmed that an inspection was carried out on the business premises just last month.
They said that no products were found to be in breach of regulations during the "tricky process" which does not take into account the application process.
It also said its power is limited due to responsibility being split between a number of different agencies.
"The council does not register premises or individuals carrying out teeth whitening, so we cannot confirm ownership details for a particular premises," they explained.
"Council's role is to ascertain the legality of products supplied by premises and individuals - the regulation of practitioners is a matter for the General Dental Council (GDC)."
But the GDC said it can only verify whether or not named individuals are regulated.
The Medicines and Healthcare products Regulatory Agency (MHRA) was unable to confirm whether "sodium-based" gels are legal without knowing the product brand.
However, The HD Smile Clinic refused to provide this information.
A spokesperson for the British Dental Association (BDA) said they are unaware of any legal agent that could provide the immediate results the Shankill Road business is promising.
Scientific advisor to the BDA, Prof Damien Walmsley, expressed serious doubts over the service being offered.
"It stretches credibility for anyone to deliver eight shades of whitening in a single sitting while operating within the law," he said.
The expert also warned prospective customers to be wary of any business making such bold claims.