Evaluation of demineralization changes in molar tissues in vitro using electrical impedance spectroscopy

Relevance. Early diagnosis of dental caries plays a key role in preventing periodontal diseases and supporting overall oral health. One promising approach for detecting pathological changes in dental tissues is electrical impedance spectroscopy (EIS), based on analysis of their frequency-dependent impedance characteristics. Objective. To develop a methodology that applies impedance spectroscopy for the quantitative assessment of tissue changes in molars at varying depths of carious lesions. Materials and methods. The study was conducted in vitro on 15 intact molars. Complex impedance was measured using an E7-20 impedance analyzer operating in the frequency range up to 1 MHz. Measurements were performed in the same region of each tooth before and after artificial demineralization. Results. Enamel demineralization was found to affect the frequency-dependent impedance characteristics of molars in vitro. An equivalent electrical circuit was proposed to model the electrical processes in individual dental tissues. Experimental data, together with numerical simulations based on the equivalent circuit, enabled determination of circuit parameters before and after demineralization. The results indicate that the observed changes in impedance spectra are attributable to alterations in the resistive and capacitive properties of enamel, while the parameters of dentin remained unaffected. These changes can be explained by increased enamel porosity resulting from demineralization. Conclusion. Analysis of frequency-dependent impedance characteristics and equivalent circuit parameters provides a means of identifying which dental tissues have undergone changes. These findings support the potential of impedance spectroscopy as a diagnostic tool for detecting early enamel demineralization.