A new dental imaging method to examine the health of patients’ gums. A mixture of squid ink, water and cornflour is applied to the gums and examined using light and ultrasound. The development team from the University of California, San Diego believe the new method could be less invasive, more comprehensive and more accurate than anything else. Dr Jesse Jokerst, senior author of the study, said: “The last time I was at the dentist, I realised that the tools that are currently being used to image teeth and gums could use significant updating”. The usual way of checking pocket depth for any signs of gum disease is with a periodontal probe, and can be invasive and uncomfortable for some patients and measurements can vary greatly between dentists. For the new method, the mouth is first rinsed with a paste made of commercially-available food-grade squid ink, water and cornflour. The rinse serves as a contrast agent for an imaging technique called photoacoustic ultrasound. This involves shining a light signal onto a sample which heats up and expands, generating an acoustic signal that researchers can then analyse. Squid ink naturally contains melanin nanoparticles, which absorb light, and during the oral rinse, these are trapped in the pockets between the teeth and gums. When lit with a laser, the paste heats and swells, creating pressure in the pockets that is detected with ultrasound. This is what enables researchers to create a full map of the pocket depth around each tooth.