Mitra has been chosen for her technique of incorporating nanoparticles into dental materials
The European Patent Office (EPO) announced that Indian-American chemist Sumita Mitra has been nominated as a finalist in the “Non-EPO countries” category of the European Inventor Award 2021. She was the first to apply nanotechnology to the production of dental materials, leading to the creation of a new composite to repair teeth, which has many advantages over conventional materials.
Mitra’s material overcomes many of the limitations of previous dental composites, which were either too weak to be used on biting surfaces, or quickly lost their polish and became physically unattractive. In addition, her invention is more versatile than other composites, meaning it can be used in any area of the mouth, and simplifies the filling procedure for dentists.
Commercialised as Filtek Supreme Universal Restorative since 2002 by 3M, the US multinational for which Mitra worked for more than 30 years, the technology and the products developed from it are today used by dentists around the globe.
“Mitra’s invention takes what was an emerging technology at the time – nanotechnology – and she applies it to a new sector to provide a solution for dentists and relief for patients,” said António Campinos, President, EPO while announcing the European Inventor Award 2021 finalists.
“Patents have protected Mitra’s material and helped ensure that her invention remains commercially successful nearly 20 years after its launch, ” he added.
The winners of the 2021 edition of the EPO’s annual innovation prize will be announced at a ceremony starting at 19:00 CEST on 17th June, 2021, which has been reimagined as a digital event for a global audience.
It was while working in the oral care division of the US multinational 3M that Mitra became aware of the limitations of the existing composite materials. At the same time, nanotechnology was emerging as a field of research and she decided to explore how these new developments could be applied to dentistry.
She began working on nanotechnology-based solutions for new dental material, driven by a desire to use her expertise in polymer chemistry and materials science to develop inventions that solve real-life problems for people.
Her idea was to replace composite fillers with nanoparticles – ultra-fine particles measuring between one and 100 nanometres in diameter – which are smaller than the wavelength of visible light and do not, therefore, scatter it, resulting in a material that retains its shine.
At first, Mitra and her team at 3M incorporated uniform nanoparticles measuring less than 20 nanometres in size into resins, but although the materials they created were strong and attractive, they were difficult to mould, making them unsuitable for dentistry.
She and her team, therefore, developed a technique for creating linked clusters of nanoparticles, which they called ‘nanoclusters,’ combining these with single nanoparticles of varying diameters, resulting in a strong, durable and shiny material, with excellent handling properties.
By adding tiny amounts of pigment and altering the chemical composition of the nanoparticles, the team also created a range of different shades, which can be matched to individual patients’ teeth, and layered to create a more natural finish.
“The use of nanotechnology gave me the opportunity of making a new material. It restores peoples’ smiles and improves the quality of their lives,” said Mitra.
Following the successful development process, she worked closely with 3M’s patent attorneys to construct the patents to protect her ground-breaking work.
Besides her contribution to the Filtek range, she is named as an inventor on 58 granted European patents for inventions that have resulted in various dental innovations, including resin-modified glass ionomers and new adhesives which can be found in other 3M products.
“The patent was essential for safeguarding the invention so that others could not infringe on the technology,” she added.
Mitra’s invention has contributed to 3M being named as one of the top three manufacturers for the global composite filling in the dental restoration market in 2019.
According to her, “The material’s strength is its versatility. You have all the desired properties of a tooth filling in one material. That is why this technology has been used to make so many different types of tooth restorations around the world.”