An international group of researchers led by Professor Owen Addison from King's College London has been able to close a gap in the knowledge of photo-activated resin-based composites, commonly used in medical and dental applications.

In a recent paper published in Nature Communications, the team from Canada, the United Kingdom, Norway and the United States described how they saw inside the resin matrix and gained insight into how filler particles interact with it during setting and influence the dental filling materials.1

Professor Addison said: 'We've been working for a number of years using synchrotron-based techniques primarily to try and understand the evolving structure of the polymer network of the resin matrix that makes up these materials.'

As the Chair of Oral Rehabilitation of King's College London's Faculty of Dentistry, Oral & Craniofacial Sciences and Adjunct Professor of Dentistry at the University of Alberta, Canada, Professor Addison has been interested in understanding the structure of these materials in order to improve their performance.

The team used a synchrotron technique that allows them to look at different resin chemistries and filler compositions. This will help researchers optimise the material, make it more resistant to wear and mechanical deterioration, and lead to less time spent in the dental clinic.

The technique, wide field mid-infrared imaging, was used at the Mid-IR beamline (https://bit.ly/2MVSsgP) at the Canadian Light Source (CLS) - a national research facility producing the brightest light in Canada - and allowed the team to gain a greater understanding of what was happening within the matrix of the resin composite. The filler particles are introduced to the material for better mechanical performance, but there has been a significant gap in the knowledge about the way these fillers affect the polymerisation, or hardening, of the material.

For the first time, the team was able to demonstrate that the fillers themselves modify the local reaction of the setting material. Professor Addison believes that this information has the potential to improve these resin composites, which would not only be an asset to dentistry but to other medical and industrial applications of photo-polymer composites.