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.

1. Li Y, Xiang Y, Ren H, Zhang C, Hu Z, Leng W, Xia L. Association between periodontitis and dental caries: a systematic review and meta-analysis. Clinical Oral Investigations. 2024;28(6):306. https://doi.org/10.1007/s00784-024-05687-2

2. Monjarás-Ávila AJ, Hardan L, Cuevas-Suárez CE, Alonso NVZ, Fernández-Barrera MÁ, Moussa C, et al. Systematic Review and Meta-Analysis of Remineralizing Agents: Outcomes on White Spot Lesions. Bioengineering. 2025;12(1):93. https://doi.org/10.3390/bioengineering12010093

3. Antonova IN, Orekhova LYU, Goncharov VD, Yashkardin RV. The results of the study of the focus of initial caries of human tooth enamel in vitro using atomic force microscopy. Stomatology. 2023;102(5):20-26 (In Russ.). https://doi.org/10.17116/stomat202310205120

4. Granko SA, Danilova DV, Beloded V. Diagnosis of initial carious lesions of hard tooth tissues. Sovremennaya stomatologiya. 2017.69(4):59-62 (In Russ.). Available from: https://www.elibrary.ru/item.asp?id=30796701

5. Kalashnikova NP, Avraamova OG, Kulajenko TV, Goryacheva VV, Khokhlova SV. Modern instrumental methods for early diagnosis of dental caries. Stomatology. 2022;101(1):89-95 (In Russ.). https://doi.org/10.17116/stomat202210101189

6. Kühnisch J, Aps JK, Splieth C, Lussi A, Jablonski-Momeni A, Mendes FM, et al. ORCA-EFCD consensus report on clinical recommendation for caries diagnosis. Paper I: caries lesion detection and depth assessment. Clinical oral investigations. 2024;28(4):227. https://doi.org/10.1007/s00784-024-05597-3

7. Kalaichev NV, Bulakhova IN, Petrova AP. Comparison of the diagnostic efficiency of caries with a laser-fluorescent method (KaVo diagnodent) and other standard and additional diagnostic methods. Mezhdunarodnyj studencheskij nauchnyj vestnik. 2018;(4-1):147-151 (In Russ.). Available from: https://s.eduherald.ru/pdf/2018/4-1/18642.pdf

8. Schwendicke F, Splieth C, Breschi L, Banerjee A, Fontana M, Paris S, et al. When to intervene in the caries process? An expert Delphi consensus statement. Clinical Oral Investigations. 2019;23(10):3691-3703. https://doi.org/10.1007/s00784-019-03058-w

9. Mu Y, Wang Y, Huang L, Weng Z, Zhong T, Yu S, et al. Yellow light and ultrasound Dual-responsive strontium-doped zinc oxide composites for dental caries prevention and remineralization. Bioactive Materials. 2025;47:403-416. https://doi.org/10.1016/j.bioactmat.2025.01.029

10. Sabti MY, Alfarhan IY, Akbar AA, Qudeimat MA. Evaluating Color Stability and Enamel Surface Roughness Following Resin Infiltration Treatment. Clinical and Experimental Dental Research. 2024;10(1):e2834. https://doi.org/10.1002/cre2.834

11. de Oliveira Rocha A, Cardoso K, Goebel MC, Santos PS, Dos Anjos LM, Ribeiro JS, et al. A global overview of enamel microabrasion for white spot lesions: a bibliometric review. Restorative Dentistry & Endodontics. 2024;49(3):е29. http://dx.doi.org/10.5395/rde.2024.49.e29

12. Kwaśny M, Bombalska A. Applications of Laser-Induced Fluorescence in Medicine. Sensors. 2022;22(8):2956. https://doi.org/10.3390/s22082956

13. Marmaneu-Menero A, Iranzo-Cortes JE, Almerich-Torres T, Ortola-Siscar JC, Montiel-Company JM, Almerich-Silla JM. Diagnostic Validity of Digital Imaging Fiber-Optic Transillumination (DIFOTI) and Near-Infrared Light Transillumination (NILT) for Caries in Dentine. Journal of clinical medicine. 2020;9:420. https://doi.org/10.3390/jcm9020420

14. Makeeva IM, Volkov AG, Prikuls VF, Dikopova NZh, Arakelian MG, Makeeva MK, Ruchkin DN. The efficacy of electroodontodiagnosis by means of various types of current. Stomatology. 2018;97(6):34-37 (In Russ.). https://doi.org/10.17116/stomat20189706134

15. Kozhevnikova AI, Kolyagina AA. Electroodontodiagnostics in the daily practice of a dentist. Bulletin of medical Internet conferences. 2016;6(5):864-867 (In Russ.). Available from: https://elibrary.ru/item.asp?id=27462344

16. Ivanova GG, Zhorova TN. Study of the statistical average electrical conductivity of hard dental tissues from the moment of their eruption in dynamics in order to diagnose pathological processes of teeth with unfinished mineralization of enamel. The dental institute. 2020;88(3):87-90 (In Russ.). Available from: https://elibrary.ru/item.asp?id=44076261

17. Mainkar A, Kim SG. Diagnostic Accuracy of 5 Dental Pulp Tests: A Systematic Review and Meta-analysis. Journal of endodontics. 2018;44(5):694-702. https://doi.org/10.1016/j.joen.2018.01.021

18. AbdELkader A, Hafez Ibrahim S, Elsayed Hassanein O. Reliability of impedance spectroscopy versus digital radiograph and ICDAS-II in occlusal caries detection: a prospective clinical trial. Scientific Reports. 2024;14(1):16553. https://doi.org/10.1016/j.joen.2018.01.021

19. Pretty IA, Ellwood RP. The caries continuum: Opportunities to detect, treat and monitor the remineralization of early caries lesions. Journal of Dentistry. 2013;41(Supplement 2):S12-S21. https://doi.org/10.1016/j.jdent.2010.04.003

20. Kockanat A, Unal M. In vivo and in vitro comparison of ICDAS II, DIAGNOdent pen, CarieScan PRO and SoproLife camera for occlusal caries detection in primary molar teeth. European journal of paediatric dentistry. 2017;18(2):99-104. https://doi.org/10.23804/ejpd.2017.18.02.03

21. Jablonski-Momeni A, Heinzel-Gutenbrunner M, Haak R, Krause F Use of AC impedance spectroscopy for monitoring sound teeth and incipient carious lesions. Clinical Oral Investigations. 2017;21(8):2421-2427. https://doi.org/10.1007/s00784-016-2038-2

22. Sannino I, Lombardo L, Angelini E, Parvis M, Arpaia P, Grassini S. Preliminary impedance spectroscopy study for carious lesions detection. In 2022 IEEE International Symposium on Medical Measurements and Applications (MeMeA) (pp. 1-6). https://doi.org/10.1109/MeMeA54994.2022.9856542

23. Melo M, Pascual A, Camps I, Ata-Ali F, Ata-Ali J. Impedance Spectroscopy as a Tool for the Detection of Occlusal Noncavitated Carious Lesions. Operative Dentistry. 2022;47(3):258-267. https://doi.org/10.2341/19-149-c

24. İpek İ, Öznurhan F, Derdiyok C, Şengül BK. Diagnostic Comparison of Different Methods for Detection of Occlusal Caries Lesions in New Erupted Permanent Teeth. Current Research in Dental Sciences. 2025;35(1):71-74. https://doi.org/10.17567/currresdentsci.1617451

25. Herencsar N, Freeborn TJ, Kartci A, Cicekoglu O. A Comparative Study of Two Fractional-Order Equivalent Electrical Circuits for Modeling the Electrical Impedance of Dental Tissues. Entropy (Basel). 2020;22(10):1117. https://doi.org/10.3390/e22101117

26. Kolumban A, Moldovan M, Țig IA, Chifor I, Cuc S, Bud M, et al. An Evaluation of the Demineralizing Effects of Various Acidic Solutions. Applied Sciences. 2021;11(17):8270. https://doi.org/10.3390/app11178270

27. Gorelikova MA, Zharikova V, Kuznetsova TA. Study of Impedance Frequency Dependences of Healthy and Depulpated Teeth. 2023 Seminar on Digital Medical and Environmental Systems and Tools (DMEST) (2023):35-38. https://doi.org/10.1109/DMEST60476.2023.10339623

28. Gorelikova MA, Goncharov VD, Yashkardin RV, Gerasimenko AE. Effects of the Measuring Sensors Frequency Response on the Interpretation of the Results of the Impedance Measuring of Hard Tooth Tissues. 2021 IEEE Conference of Russian Young Researchers in Electrical and Electronic Engineering (ElConRus). 2021:1756-1759. http://dx.doi.org/10.1109/ElConRus51938.2021.9396345