Electrical properties of resin monomers used in restorative dentistry

Abstract

Objectives The application of an electric field has been shown to positively influence the impregnation of the resin monomers currently used in dentin bonding systems during hybrid layer formation. This study presents an experimental characterization of the electrical properties of these monomers with the aim of both correlating them to their chemical structures and seeking an insight into the mechanisms of the monomer migration under an applied electric field. Methods Some common monomers examined were TEGDMA (triethyleneglycol dimethacrylate), HEMA (2-hydroxyethyl methacrylate), UDMA (urethane dimethacrylate), 2-MP (bis[2-(methacryloyloxy)ethyl] phosphate, TCDM di(hydroxyethyl methacrylate) ester of 5-(2,5-dioxotetrahydrofurfuryl)-3-methyl-3-cyclohexenyl-1,2-dicarboxylic anhydride) and Bis-GMA [2,2-bis(4-2-hydroxy-3-methacryloyloxypropoxyphenyl)propane]. A customized cell produced for the measurement of the electrical properties of monomers was manufactured and electrical conductivity and permittivity of resin monomers were measured. Results The permittivity of the tested monomers is largely affected by electrical frequency. The large values of permittivity and dielectric losses observed as frequency decreased, indicate a dominant effect of ionic polarization, particularly evident in materials showing the highest conductivity. Permittivity and conductivity of the tested monomers showed a similar behavior, i.e. materials with the lowest permittivity also show small values of conductivity and vice versa. Significance The results of the present study revealed a good correlation between electrical properties and Hoy solubility parameters and, in particular, the higher the polar contribution (polar forces plus hydrogen bonding) the higher the permittivity and conductivity. The most relevant outcome of this study is that the electrophoretic mechanism prevails on the electroendoosmotic effect in determining the monomer migration under the application of electric fields.

Optimization of direct currents to enhance dentine bonding of simplified one‐step adhesive

“…Recent research showed that migration of adhesive monomer in an electric field may be affected by several parameters, including current intensity, chemical structure, and charge of adhesive molecules . The research demonstrated that the migration rate of ionic adhesive monomers correlated directly with the intensity of the applied voltage .…”

Brainstem Stimulation Increases Functional Connectivity of Basal Forebrain-Paralimbic Network in Isoflurane-Anesthetized Rats

“…As illustrated in the figure, the EEG pattern recorded during image acquisition was essentially free from artifacts. Typically, gradient-induced artifacts can saturate the EEG signal due to the switching gradients; however, our EEG signals were minimally affected presumably because of the rigidity (minimized vibration in the lead wires), insulation, and circuit-loop area reduction provided by encapsulating the electrode wires with a methylmethacrylate-based orthodontic component resin (Breschi et al, 2012;Khaii et al, 2007;Sword et al, 2008;Van Landuyt et al, 2007;Vasios et al, 2006). PnO stimulation produced a transient artifact in the EEG that typically lasted for 2-3 sec.…”

“…Orthodontic resin (DENTS-PLY Caulk, Milford, DE) was then applied on the left cranium to create one unit (recording electrodes, nylon screw, and stimulating electrode). To minimize the gradientinduced artifact on the EEG, the remaining portion of the platinum recording electrode wires was further insulated using methyl-methacrylate-based orthodontic resin to minimize the circuit loop area through which noise induced by time-varying magnetic fields could be introduced, to provide greater rigidity in order to reduce vibrations in the lead wires (Vasios et al, 2006), and due to its dielectric properties (Breschi et al, 2012;Park et al, 2007;Sword et al, 2008;Tomar et al, 2012;Van Landuyt et al, 2007). The platinum electrodes were then subsequently bent 90°such that the pedestal lay parallel to the dorsal surface of the head.…”

Calculation of the Currents Generated in Dental Tissues by the Application of an External Electric Field

“…Moreover, the tooth model can be further modified to include restorative materials with specified electrical properties [2].…”

“…By applying a dc voltage between an application sponge filled with an adhesive and the etched tooth substrate a constant electric flow during the adhesive application is created. An insight into the mechanisms of monomer migration under the application of an electric field can be found in [2], where the electrical properties of the resin monomers are measured and it is shown that the electrophoretic effect is enhanced by high values of electrical conductivity. These findings may be used to quantify the effect of electric currents on impregnation of monomers with a modelling approach.…”