Former Perth Dental Rooms director David Hurst, 43, took his own life on December 10 last year at the Crown Perth, leaving a path of destruction and a business on the brink of bankruptcy.
Lawyers allege Dr Hurst withdrew $7m from the Perth practice before he took his own life.
Dr Hurst was previously convicted of defrauding the National Health Service (NHS) in the UK over forged patient declarations.
The Cardiff Crown Court found that Dr Hurst stole 拢15,584 ($A35,553) by submitting fraudulent patient claims while he worked at the Bridgend Dental Centre.
He pleaded guilty to 69 counts of theft, receiving a suspended sentence and order to perform 200 hours of community service, in 2012.
Two years later he was banned from practising dentistry in the UK by a professional conduct committee.
But the dentist relocated to West Australia, where he was permitted to practise dentistry despite his criminal record.
He became a director at the Perth Dental Rooms, where he allegedly defrauded patients before his death.
Legal firm Slater and Gordon is representing 20 of Dr Hurt鈥檚 former patients whom he allegedly persuaded to use their superannuation to pay for expensive and often unnecessary treatments.
The lawyers allege some patients paid more than $70,000 upfront for procedures that never occurred and have yet to be reimbursed.
Medical law practice leader Sarah Marshman said patients had suffered financial loss, emotional distress and ongoing pain caused by reckless, unfinished and, in some cases, unnecessary dental work.
She said the firm heard from patients who were in constant pain, had broken implants, infections and untreated complications.
鈥淔or many patients, accessing their superannuation early seemed like a smart way to fund dental treatment,鈥 she said.
鈥淏ut now they鈥檝e lost tens of thousands from their retirement savings and are still in pain 鈥 physically, financially and emotionally.
鈥淭hese patients weren鈥檛 just sold dental procedures. They were sold false hope through aggressive social media advertising and quick access to super.
鈥淭hey were encouraged to dip into their retirement savings without any real understanding of the tax penalties or medical risks involved.鈥
Ms Marshman urged Australians to think twice before being pressured by aggressive advertising to use super for medical or dental work.
鈥淲e鈥檙e continuing to gather evidence for a growing number of affected patients and will be seeking accountability for the harm caused,鈥 she said.
鈥淲e believe there could be over 130 former patients affected.鈥
An administrator was appointed to Hurst Group Pty Ltd, which traded as the Perth Dental Rooms, in March this year after Dr Hurt鈥檚 wife Clara stepped in as director. There is no suggestion that she was involved in any wrongdoing.
The West reported the Perth Dental Rooms was sold in May but proceeds from the sale were not enough to cover its liabilities.
It was reported $2.3m in payments made by patients in advance remain unaccounted for by the Hurst Group.
Ms Marshman urged anyone who was treated or consulted by Dr Hurst to contact Slater and Gordon Lawyers.
鈥淎ny information received will be treated confidentially and could help bring justice to the victims of David Hurst,鈥 she said.