Richard Billington [Dental Physical Sciences, Queen Mary University of London, Barts & The London School of Medicine & Dentistry]
From school I worked in food quality control then with ionizing radiation on polymers. My degree was in polymer chemistry and plastics technology. I worked for Unilever on hair products and keratin chemistry. For Wilkinson Sword I researched the polymer coatings on razor blades, steel electrochemistry, and plasma coating technology. In 1989 I joined DENTSPLY. Research there resulted in highly commercially successful glass ionomers, amalgams, polycarboxylates, and dentine bonding agents. I subsequently helped to found Advanced Healthcare which became part of Shofu.
My interest have been directed to the properties and interactions of dental materials, particularly glass ionomers, with their environment, their users, other oral products and types of radiation.
One particular interest has been the interaction of glass ionomer cements with fluoride solutions. In 1990 we presented work World Biomaterials Conference Berlin where we showed that if a “mix-with-water”glass ionomer was mixed with fluoride solution the subquent F ion release increased but if immersed in the same solution vastly more F– ions were found to be released. The same effect was found for K+ ions.
Understanding this effect has proved difficult if fascinating to research. Using a SIMS beam to analyse the F content of the surface and then to sputter away cement the surface F concentration even higher than the overall one.
Another area of interest is the interaction between dental materials and their users. From talks I gave young dentists it was clear from their reactions that they did not get cement restoratives mixed at their proper ratio of powder to liquid adversely affecting properties.
Additionally users were accustomed to resin restoratives which were command set by u.v. or light. Since glass ionomers were not set this way we investigated ultrasound as an alternative with the Sonochemistry Department of Coventry University in 1985. This has been a continuing interest and the effects of ultrasound not only the setting reaction but also on changes in F- ion release have been reported.
A further interest in glass ionomer properties relates to their changes in properties over maturation times greater than 24 hours. For some properties such erosion and abrasion resistance all materials improve whereas for others such as strength increases and reductions are observed. Attempting to understand this is a current interest