Using Teeth to Treat Hearing Loss

Ear photo via Shutterstock

Boston Medical Center (BMC) is treating single-sided deafness using SoundBite, a new hearing system that relies on bone conduction—the ability of sound waves to travel from teeth through the bones in the skull to vibrate the delicate hair cells of the inner ear of the working ear. Approximately 8 million Americans were born with single-sided deafness and 1.5 million develop it later in life.

There are two components to the system. First, a removable in-the-mouth (ITM) hearing device is placed in the mouth that fits around the upper, left, or right back teeth. Second, a small behind-the-ear (BTE) microphone unit is put on the hearing impaired ear. The BTE unit uses a digital signal processor to process the sound, and a wireless chip transmits the sound signals to the ITM device. Once the ITM picks up the signals, it converts them into imperceptible sound vibrations that travel via the teeth, through the bone and to the working cochlea (the auditory portion of the inner ear).

Once the device is recommended for a patient, they need to visit a dentist to check for any tooth or gum problems, and then a mold is made. The customized mouth device is created from the mold. Bing Liu, DMD, an assistant professor at Boston University Goldman School of Dental Medicine says that most people can be fit for the device. “In most cases, as long as a patient has two adjacent back teeth on one side of the upper jaw, we can fit them for the device.”

Kenneth Grundfast, MD, chief of the department of otolaryngology at BMC  has several patients using the device. “This system allows us to bypass the middle and outer ear entirely, rerouting the sound from the impaired ear directly into the good cochlea,” Grundfast says. “By capturing sound from the side of head where the ear is not working and bringing it into the good ear, patients can function better in social settings such as meetings, sitting at a table in a restaurant, or walking along with someone who is by their side and speaking to them thinking that they can hear in the ear that has no hearing capability.”