TY - JOUR
T1 - Monitoring bacterial-demineralization of human dentine by electrochemical impedance spectroscopy
AU - Xu, Zhang
AU - Neoh, Koon Gee
AU - Amaechi, Bennett
AU - Kishen, Anil
PY - 2010/2
Y1 - 2010/2
N2 - Objective: The purpose of this study was two-fold: (1) to monitor bacterial biofilm formation and bacteria-induced demineralization of dentine in situ by using electrochemical impedance spectrum (EIS); (2) to examine the relationship between EIS findings and changes in the chemical composition and ultrastructure of dentine during bacteria-induced demineralization. Methods: In this study, dentine demineralization was induced by Streptococcus mutans (ATCC 25175) in the presence of sucrose in culture medium and was monitored using two EIS measurement systems (Type A with a working electrode and Type B without a working electrode). Scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) were employed to examine the morphology, element contents and crystallinity of hydroxyapatite (HAP) on the dentine surface. Transverse microradiography (TMR) was used to characterize the lesion depth and degree of mineral loss during demineralization. Results: The resistance of the bulk dentine (Rd) and the apparent resistance of dentine (Ra) measured from the Type A and Type B EIS systems, respectively, decreased gradually with demineralization. The resistance of the biofilm formed on dentine surface was determined by fitting the EIS data with equivalent circuits. The presence of biofilm slightly increased Ra of dentine before demineralization. However, the electrochemical behavior of biofilm did not affect the decreasing impedance of dentine with demineralization. The SEM, EDX, XRD and TMR results demonstrated that the surface and bulk dentine gradually became more porous due to the loss of minerals during demineralization, which in turn resulted in the decrease in Rd and Ra values obtained from EIS systems. Conclusions: This investigation highlighted EIS as a potential technique to monitor biofilm formation and bacterial-induced demineralization in situ.
AB - Objective: The purpose of this study was two-fold: (1) to monitor bacterial biofilm formation and bacteria-induced demineralization of dentine in situ by using electrochemical impedance spectrum (EIS); (2) to examine the relationship between EIS findings and changes in the chemical composition and ultrastructure of dentine during bacteria-induced demineralization. Methods: In this study, dentine demineralization was induced by Streptococcus mutans (ATCC 25175) in the presence of sucrose in culture medium and was monitored using two EIS measurement systems (Type A with a working electrode and Type B without a working electrode). Scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) were employed to examine the morphology, element contents and crystallinity of hydroxyapatite (HAP) on the dentine surface. Transverse microradiography (TMR) was used to characterize the lesion depth and degree of mineral loss during demineralization. Results: The resistance of the bulk dentine (Rd) and the apparent resistance of dentine (Ra) measured from the Type A and Type B EIS systems, respectively, decreased gradually with demineralization. The resistance of the biofilm formed on dentine surface was determined by fitting the EIS data with equivalent circuits. The presence of biofilm slightly increased Ra of dentine before demineralization. However, the electrochemical behavior of biofilm did not affect the decreasing impedance of dentine with demineralization. The SEM, EDX, XRD and TMR results demonstrated that the surface and bulk dentine gradually became more porous due to the loss of minerals during demineralization, which in turn resulted in the decrease in Rd and Ra values obtained from EIS systems. Conclusions: This investigation highlighted EIS as a potential technique to monitor biofilm formation and bacterial-induced demineralization in situ.
KW - Bacterial-induced demineralization
KW - Dentine
KW - Electrochemical impedance spectroscopy (EIS)
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U2 - 10.1016/j.jdent.2009.09.013
DO - 10.1016/j.jdent.2009.09.013
M3 - Article
C2 - 19804810
AN - SCOPUS:74449084090
SN - 0300-5712
VL - 38
SP - 138
EP - 148
JO - Journal of Dentistry
JF - Journal of Dentistry
IS - 2
ER -