When visiting the dentist, you might remember being poked and prodded by a thin metal instrument to check your teeth and gums. This technique, called periodontal probing, is used to look for signs of gum disease. Now, researchers publishing in ACS Sensors report a toothbrush-shaped ultrasound transducer that can provide a less invasive screening for gum disease. In proof-of-concept demonstrations on animal tissues, the device produced measurements similar to those of a manual probe.

Gum disease is a common condition affecting tissue that surrounds and supports teeth. If left untreated, it causes the gums to pull away from the teeth, creating pockets where harmful bacteria can grow. Currently, manual periodontal probing is the standard way to check for gum disease, but the technique is uncomfortable and can miss early stages. So, Jesse Jokerst and colleagues developed a small, noninvasive ultrasound method capable of imaging teeth and gums—even hard-to-reach molars and premolars at the back of the mouth.

Ultrasounds work by sending sound waves into the body. When the sound waves encounter a structure, like gum tissue or a tooth, they are reflected and detected by a transducer. The transducer then converts the reflected sound waves into an image. Currently, most ultrasound transducers have large heads that are about the same size as a wireless earbuds case. Although they work for larger parts of the body, these transducers cannot access smaller spaces like those in the mouth. Smaller transducers that are about half the length and width of traditional devices are available, but current models have limited image resolution because they are only able to produce and detect low frequencies. To overcome these limitations, the researchers created an even smaller toothbrush-shaped transducer that operates at a higher frequency and can produce high-quality images of teeth and gums.

To test the transducer's accuracy, the researchers used the new instrument to measure the gum thickness and gum height of pig teeth. Then the researchers repeated the measurements using a manual metal periodontal probe. After analyzing the correlation between the two sets of measurements, the team found that the ultrasound measurements were statistically similar to those of the manual technique. The results support the reliability of the toothbrush-shaped transducer as a less invasive technique for monitoring gum health.

"We designed this tool to meet the realities of clinical dentistry—it is miniaturized, accurate and easy to use. Future work will use this device with patients to image below the gumline, where we will monitor treatments and diagnose earlier to reduce dental pain and help patients keep a healthy smile," says Jokerst.