Electrolytic Dissociation of Dental Hard Tissues Caused by Oral Galvanism

Objectives: Since electrostatic fields and electric currents caused by different metallic restorative or denture materials can lead to dialysis of hard tissues of teeth (CHASE, 1879), the objective of this study was to analyse the loss rate of tooth substances resulting from galvanic processes.

Methods: For this purpose, equal discs (diameter/thickness=10x1mm) of enamel and dentine material were sectioned from bovine teeth. The samples were exposed to homogenous electric fields generated inside a pseudo-realistic device containing two fine gold sheet electrodes and 0.9% saline as an electrolyte. Following parameters were varied: (a) field strength between the electrodes between 0 (control) and 25 V/m, and (b) position of the samples of dentin without (D0), one sided (D1) or both sided (D2) contact to the electrodes, and of enamel without (E0), one sided (E1) or both sided (E2) contact. Calcium concentration of the electrolyte was determined using ICP-OES (315 nm) at 0, 1, 2, 3 and 24 hours. Data was evaluated statistically utilizing the test of TUKEY-KRAMER and post-hoc correction according to BONFERRONI (α=.05).

Results: Already after 2 hours, concentration of Ca²⁺ inside the electrolyte was increased significantly (p<.001) by about 250% for E0 and by 350% for D0 when electric field strength amounted to 17 V/m. Moreover, electrolytic dissociation of Ca²⁺ was greater for E1 (+250%) and E2 (+500%) as well as for D1 (+590%) and D2 (+1500%) compared to the control.

Conclusions: Within the limitations of this study, it was shown that decay of hard tissues of teeth is decisively correlated with an increase of electric field strength caused by different metallic dental materials. Thereby, any contact of dental hard tissues with the metallic electrodes intensifies decay much more.