Silica Particles Could Fix Damaged Teeth

Image courtesy of renjith krishnan at


Image courtesy of renjith krishnan at

The development of coated silica nanoparticles could be used in the restorative treatment of sensitive teeth and prevent the onset of tooth decay, according to researchers at the University of Birmingham.

Published in the Journal of Dentistry, the study shows how sub-micron silica particles can be prepared to deliver important compounds into damaged teeth through tubules in the dentine. The tiny particles can be bound to compounds ranging from calcium tooth building materials to antimicrobials that prevent infection.

“The dentine of our teeth have numerous microscopic holes, which are the entrances to tubules that run through to the nerve,” said professor Damien Walmsley of the university’s school of dentistry.

“When your outer enamel is breached, the exposure of these tubules is really noticeable. If you drink something cold, you can feel the sensitivity in your teeth because these tubules run directly through to the nerve and the soft tissue of the tooth,” Dr. Walmsley said.

“Our plan was to target those same tubules with a multifunctional agent that can help repair and restore the tooth, while protecting it against further infection that could penetrate the pulp and cause irreversible damage,” he said.

Restorative agents are used to increase the mineral content of both the enamel and dentine. The particles act like seeds for further growth that would close the tubules.

Previous attempts have used compounds of calcium fluoride, combinations of carbonate-hydroxypatite nanocrystals, and bioactive glass, but all have seen limited success as they are liable to aggregate on delivery to the tubules. This keeps them from being able to enter the opening, which is only one to 4 µm wide.

However, the Birmingham team turned to sub-micron silica particles that had been prepared with a surface coating to reduce the chance of aggregation. Using high-definition scanning electron microscopy, the researchers saw promising signs suggesting the aggregation obstacle had been overcome.

“These silica particles are available in a range of sizes, from nanometer to sub-micron, without altering their porous nature. It is this that makes them an ideal container for calcium-based compounds to restore the teeth, and antibacterial compounds to protect them,” said professor Zoe Pikramenou of the university’s school of chemistry.

“All we needed to do was find the right way of coating them to get them to their target. We have found that different coatings do change the way that they interact with the tooth surface,” Dr. Pikramenou said.

The researchers tested different options to see which would allow for the highest level of particle penetration into the tubules and identified a hydrophobic coating that could lead to an effective agent, she said. Next, the researchers will optimize the coatings to see how effective the particles are in blocking the communication with the inside of the tooth.

“The ultimate aim is to provide relief from the pain of sensitivity,” Dr. Pikramenou said.