Tauranga dental technology company Rhondium has received approval from the US Food and Drug Administration (FDA) for its innovative One Visit Crown.

"This means we can enter and sell into the US market," said chairman Simon McDonald, who set up Rhondium in late 2013 after selling his successful Katikati-based company Triodent to US-owned multinational Dentsply.

Getting a crown done traditionally involves an initial visit so the dentist can prepare the tooth for the crown and take a rubber impression of the stump, which is then sent to a lab so a crown can be made, which is sent back to the dentist so it can be bonded to the stump. Rhondium's One Visit Crown allows the dentist to complete the entire process in one session.

"We enable the dentist to do a crown in half the time and at half the cost without needing to send it out to the lab," said Dr McDonald.


The original idea came from New Zealand dentist Dr Adam Doudney and was developed with Dr McDonald and his research team.

Rhondium began preparing for the FDA submission about a year ago and the rigorous approval process was handled by a Washington-based law firm experienced in the FDA regulatory arena.

"We have had to put a vast amount of documentation together," said Dr McDonald.

FDA approval can take up to 90 days once submitted. Dr McDonald said the FDA came back to Rhondium part-way through the process seeking some clarifications and changes. These included adding more information in the documentation for users, and conducting additional biochemical compatibility tests on one of the plastics used in part of the insert.

"We agreed to everything they wanted because there was nothing that was problematic for us," he said.

Rhondium plans to market directly in the US, initially through about 15 key opinion leader dentists across the country that Dr McDonald had worked with previously. The company will begin by targeting the vast California market.

"Our experience in New Zealand is that the product needs people who are familiar with it to use it and encourage and teach other dentists."

Garry Burt, owner of the Dental Centre in Te Puke, said the One Visit Crown added another tool in the dentist's box and he was offering it as an alternative for patients.

"There's a significant learning curve involved," he said.

"They are not particularly easy to do, but there's a nice aesthetic result. It's half the cost of a conventional crown, which is an advantage, and you can do it all in-house."