A team of researchers and engineers from the University of California San Diego have found a new use for food-grade cuttlefish ink – to detect gum disease. Dental imaging for gum disease at present has been developed and modified using this technique. The team of researchers used a combination of cuttlefish ink with light and ultrasound as a dental imaging technique to examine a patient’s gums. It provides three advantages over traditional imaging techniques – it is noninvasive and painless, more comprehensive and more accurate. The study entitled, “Photoacoustic Imaging for Non-Invasive Periodontal Probing Depth Measurements,” was published on 7th September 2017 in the Journal of Dental Research.
At present a tool called the periodontal probe is used to assess the gum health by dentists. It is a hook like metal tool that has tiny markings like a scale or a measuring stick. It is inserted into the gap between the teeth and the gums to check how much of the teeth are exposed by the gums shrinking back from the teeth. This shrinkage leads to pockets from where damage might begin. The scales on the periodontal probe thus measure the depth of this pocket. Up to one to two millimeters of this pocket indicates healthy gums while three millimeters and deeper pockets mean gum disease. Dentists rely on this probing as one of the most reliable tools for measurement of gum disease. This probing however as is evident from the description, is a painful, uncomfortable and invasive process. Further it can measure depth of one pocket at a time. Each of the pockets for example needs to be measured separately. In addition there is a variation between the measurements that come from different dentists as the whole process is done manually and there may be subjective variations.
Jesse Jokerst, a nanoengineering professor at UC San Diego and senior author of the study said the idea to develop this novel state of the art technique came to him when he was on his dentist’s visit himself and he realized that the tools used for imaging teeth and gums need to be upgraded to be better and more accurate. As an improvement over the periodontal probe the team designed a method that could uniformly measure the entire pocket depth accurately without the painful probing of each of the pockets. Jokerst explained that using the probe is like measuring something in a dark room with a flashlight. Thus only one area or region can be inspected at a time. This new method is like illuminating the whole room to check out all the nooks and crannies.
The new method involves some steps, the first of which is to rinse the mouth with a paste that comprises of commercially available food-grade cuttlefish ink, corn starch and water. The ink would be the contrast agent that can be detected at the pockets. The ink contains melanin nanoparticles that can absorb light. After the rinse these nanoparticles get stuck within the pockets between the gums and the teeth. The next step is to use the imaging technique called photoacoustic ultrasound. For this a short pulse of laser light is shone on a sample. With the laser the area heats up and expands by a fraction. This expansion releases an acoustic signal that can be picked up by the ultrasound. This gives a clear ultrasound picture of the whole area i.e. all the teeth and the complete gums.
For starters the team tested their hypothesis on a pig model comprising of 39 teeth. Of these 12 teeth were created with artificially deeper pockets. They compared the measures taken by this technique with the William’s periodontal probes. While measurements with the probes varied greatly with different assessors, the measures using this new technique remained uniform. Jokerst said this technique scored in terms of its uniformity across measurements.
The next step would be to collaborate with the dentists so that testing on humans can begin. The team says the future steps would also look at how to reduce the unpleasant taste of the ink rinse that’s salty and bitter and use of less expensive LED lights instead of lasers to achieve the same results.