When you have tooth decay (caries), the dentist will remove the affected part of the tooth by drilling the decay and then restore it by inserting a filling. Before the cavity is filled, all of the decay must be removed, otherwise it will continue to progress underneath the filling. Knowing whether all the decayed tooth has been removed is usually done manually and can be subjective based on the instruments used.
Professor Josette Camilleri, Head of Dentistry at University of Birmingham, brought a selection of teeth to the IMAT beamline at ISIS to see if it was possible to use neutrons to measure how much of the decay had actually been removed from a tooth using the usual procedure.
Working with scientists from Diamond Light Source, Josette had already used the I18 beamline to image tooth sections and assess the calcium and phosphorus quantity in different layers. Using neutron tomography enabled her to measure a whole tooth and build a 3D image, offering the possibility of non-destructive testing as neutrons pass through the enamel surface and highlight the softer tissues inside the tooth.
For the experiment, she measured a healthy tooth as well as one subject to decay, some that had been partially excavated, and some that had restorations. She was hoping to see the change in the mineralisation of the teeth, which is an indication of the extent of decay.
The results will help dentists to understand when they have removed all the tooth tissue that has been affected by decay and inform treatment methods, preventing any further spread of infection.
Image, right: the teeth measured on IMAT.
