The influential work of Sumita Mitra

Sumita Mitra, MS, PhD has left her mark on nanotechnology and dental materials for more than three decades. Though she has been retired for more than ten years, her influence and her work continues--and her work with the School of Dentistry’s Minnesota Dental Research Center for Biomaterials and Biomechanics (MDRCBB) makes up a large part of that influence.

Mitra is an expert in new materials technology platforms for the dental and orthodontics market, having received over 100 patents and having published more than 100 papers in the areas of polymer science, nanocomposites, and dental materials. Most recently, Mitra was recognized as the winner of the European Inventor Award in the 2021 Non-European Patent Office category for her work on Filtek Supreme, a universal restorative composite she and her team developed at 3M in connection with the MDRCBB evaluation technologies.

Mitra’s work with the MDRCBB inspired the line of development that culminated in Filtek Supreme. A corporate scientist for 3M, she joined the MDRCBB as Industrial Director to study the development of resin-modified glass ionomers and other materials. “During that time, I spent many hours at the center, and even had an office on the 16th floor of Moos Tower,” Mitra recalled.

It was in this environment that Mitra started working on what would eventually become Filtek Supreme and would revolutionize the world of dental esthetics. “I became quite interested in the emerging science of nanotechnology, and realized there was an opportunity to develop a new type of dental composite filling material using novel nanoparticles as the filler,” she explained. She tested her belief that the material would be longer-lasting, mechanically strong, and durable.

Mitra and her team studied these materials, finding them lacking in the requirements she’d set forth, before ultimately developing the concept of nanoclusters and combining them with nanomeric particles to create a strong, long-lasting esthetic that was commercialized as 3M Filtek Supreme Universal Restorative in 2002.

“MDRCBB played a pivotal role during the development process,” Mitra recalled. “The innovative evaluative techniques like the ART (Artificial Resynthesis Technology) chewing machine, simulated toothbrushing machine, fracture toughness of pristine and stress materials, and more at the Center helped us to quickly study hundreds of different formulations and identify suitable candidates for future development.” Mitra expressed her gratitude for the center’s “responsiveness and their advice throughout the development process,” noting that continued work between 3M and the MDRCBB has fostered an even better and newer family of Filtek products.

The artificial mouth allowed for faster, more accurate results along the way, explained William Douglas, BDS, MS, PhD, professor emeritus and former director of the MDRCBB. “It had a vast database of what worked and what did not, in short order.”

The artificial mouth was one part of a strong partnership between the MDRCBB and 3M, seeking to improve patient care and improve the field of dentistry. “The driving principle has always been the needs of the dentist and the care of the patient,” Douglas explained. “This is a multifactorial commitment. The material must do no harm to adjacent tissues, and it must survive in the mouth.”

Today, Mitra serves as a partner in an independent consulting firm, is a member of the Board of Minnesota Independent Schools Forum, and guest lectures at several colleges and universities. But she considers the time period where she worked so closely with William Douglas, Alex Fok, PhD, MSc, Conrado Aparicio, PhD, MSc Eng, and Ralph DeLong, PhD, DDS, MS, among others, a highlight in her career.

“It always felt like we were on the same team,” Mitra reflected.

Those members of the MDRCBB agree with Mitra’s assessment. Douglas joyfully recalled his time working with Mitra on what they then called Nautilius, then Basketball, code-names for Filtek Supreme and other materials during their development and optimization. “We always worked under code names,” Douglas explained. “All of this was intense work and required a deep understanding with our liaison partner.”

Fok, who now directs the MDRCBB, noted that the collaboration with 3M goes much deeper than the development of materials. “Our clinical colleagues regularly give lectures at 3M, explaining the needs of dentists for innovative oral care solutions,” he said. “These give 3M scientists the ideas to conceive and develop new materials and technologies, and the MDRCBB joins in to assess the likelihood of success.”

Heather Conrad, DDS, MS, FACP, FRCD(C), interim chair of the Department of Restorative Sciences, called Mitra a “trailblazer for dentistry,” recognizing that the collaboration between 3M and the MDRCBB has resulted in more than one billion restorations worldwide.

“I have so many fond memories of the MDRCBB,” Mitra reflected on the partnership. “I spent many hours there, awed by the world-class techniques developed for fast in vitro evaluation of dental materials. I will always cherish the friendships that I have formed in the past and present with professors and staff at the MDRCBB. They have enriched my life, and I value that immensely.”

Sumita Mitra, MS, PhD
Sumita Mitra, MS, PhD