Researchers at the University of Birmingham have shown how coated silica nanoparticles could be used for the restorative treatment of sensitive teeth and to help prevent the onset of tooth decay.

The study, published in the Journal of Dentistry, reports how sub-micron silica particles can be prepared to deliver important compounds into damaged teeth through tubules in the dentine that lies beneath the outer tooth enamel. The tiny particles could be bound to compounds that range from calcium tooth-building materials to antimicrobials for preventing infection.

"Our plan was to target tubules [in the teeth] 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."Damien Walmsley, University of Birmingham

"The dentine of our teeth have numerous microscopic holes, which are the entrances to tubules that run through to the nerve," explained Damien Walmsley from the 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."

"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."

The aim of restorative agents is to increase the mineral content of both the enamel and the dentine, with the particles acting like seeds for further growth that would close the tubules. Previous attempts have used calcium fluoride, carbonate-hydroxypatite nanocrystals and bioactive glass, but all have seen limited success as these materials are liable to aggregate on delivery into the tubules. This prevents them from being able to enter the tubule opening, which is only 1–4µm wide.

So the Birmingham team turned to sub-micron silica particles prepared with a surface coating to reduce the chance of aggregation. When observed using high definition SEM (scanning electron microscopy), the researchers saw promising signs that suggested that the aggregation obstacle had been overcome.

"These silica particles are available in a range of sizes, from nanometre to sub-micron, without altering their porous nature," said Zoe Pikramenou from the School of Chemistry. "It is this that makes them an ideal container for calcium-based compounds to restore the teeth, and antibacterial compounds to protect them. 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."

"We tested a number of different options to see which would allow for the highest level of particle penetration into the tubules, and identified a hydrophobic surface coating that provides real hope for the development of an effective agent."

The next steps are to optimize the coatings and then see how effective the particles are at blocking communication with the inside of the tooth. The ultimate aim is to provide relief from the pain of sensitivity.

This story is adapted from material from the University of Birmingham, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.