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Trials begin on lozenge that rebuilds tooth enamel

Before too long, you may be able to buy a breath mint that rebuilds your tooth enamel while it whitens your teeth, thanks to a team of University of Washington researchers.

The team is preparing to launch clinical trials of a lozenge that contains a genetically engineered peptide, or chain of amino acids, along with phosphorus and calcium ions, which are building blocks of tooth enamel. The peptide is derived from amelogenin, the key protein in the formation of tooth enamel, the tooth’s crown. It is also key to the formation of cementum, which makes up the surface of the tooth root.

Each lozenge deposits several micrometers of new enamel on the teeth via the peptide, which is engineered to bind to the damaged enamel to repair it while not affecting the mouth’s soft tissue. The new layer also integrates with dentin, the living tissue underneath the tooth’s surface. Two lozenges a day can rebuild enamel, while one a day can maintain a healthy layer. The lozenge – which can be used like a mint – is expected to be safe for use by adults and children alike.

Graphic of calcium building lozenge
The lozenge uses a genetically engineered peptide, along with phosphorus and calcium ions, to build new layers of enamel on teeth.

The researchers have been discussing commercial applications with potential corporate partners, according to Professor Mehmet Sarikaya, the team leader. He is a professor in the Department of Materials Research Science and Engineering and adjunct professor in the Department of Oral Health Sciences. Also playing a critical role is Dr. Sami Dogan of the School of Dentistry’s Department of Restorative Dentistry faculty.

The lozenge produces new enamel that is whiter than what tooth-whitening strips or gels produce. It has another distinct advantage: Conventional whitening treatments rely on hydrogen peroxide, a bleaching agent that can weaken tooth enamel after prolonged use. Since tooth enamel can’t regrow spontaneously, the underlying dentin can be exposed, with results ranging from hypersensitivity to cavities or even gum disease. The lozenge, on the other hand, strengthens, rebuilds, and protects teeth.

While fluoride can also fortify tooth enamel, it does not actively rebuild it. It also dilutes relatively quickly, and its overall effectiveness depends largely on diligent oral hygiene. At the same time, the lozenge can also be used in conjunction with fluoride, Dr. Dogan said. The fluoride can be in a very low concentration, he added – about 20 percent of what is found in most fluoride toothpastes.

“We have three objectives in the clinical trial,” Professor Sarikaya said. “First, demonstrate efficacy. Second, documentation. Third, benchmarking – seeing how the whitening effect compares to existing commercial treatments.” The researchers have already tested the lozenge on extracted teeth from humans, pigs, and rats, and also on live rats.

The team also plans to develop related products for use in dental offices, Dr. Dogan said, expecting this phase of trials to start in March or April. “Each study will take two weeks, and we expect these trials to take no more than three months,” he said. The team is also developing a toothpaste for over-the-counter use, but has not fixed a timetable for its introduction.

In addition, the researchers are investigating a gel or solution with the engineered peptide to treat hypersensitive teeth. This problem results from weakness in the enamel that makes the underlying dentin and nerves more vulnerable to heat or cold. Most common products currently on the market can put a layer of organic material on the tooth and numb nerve endings with potassium nitrate, but the relief is only temporary. The peptide, however, addresses the problem permanently at its source by strengthening the enamel.

The idea for the lozenge design originated with Deniz Yucesoy, a graduate student in the UW’s Genetically Engineered Materials Science and Engineering Center who received a $100,000 Amazon Catalyst grant through CoMotion, UW’s commercialization center, to support the initial project. Key contributions also came from Hanson Fong, a research scientist in the Department of Materials Science and Engineering.