A system, instrumentality, and method for performing an oral care evaluation of a user via electrical impedance tomography (EIT). For example, a system may include an oral care device having a first member housing a first electrode. The first electrode may be configured to transmit a first signal through a gingiva of a user to cause an altered first signal. The oral care device may have a second member housing a second electrode. The second electrode may be configured to receive the altered first signal. The system may be configured to generate an electrical impedance tomography (EIT) profile of the gingiva of the user, for example, based on data indicative of the first signal and the altered first signal. An oral health characteristic of the user may be determined based on the EIT profile of the gingiva of the user.
