A novel array chip to monitor in situ composite degradation using electrochemical impedance spectroscopy

Objectives. This paper presents a novel array-chip technology used to monitor the physical properties of dental composites in situ. The DECAY chip (Degradation via Electrochemical Array) leverages microfabrication techniques to construct a uniform array of recessed wells that may be filled with dental restorative materials (e.g. composite or amalgam) and analyzed electrochemically in solution. Methods. The array enables the uniform preparation of multiple specimens and reference controls on a common substrate, all of which may be simultaneously evaluated. The DECAY-chip presented here consists of a 3 x 3 array of 100 mu m deep wells, and is used to monitor the degradation of a common dental composite as a function of time. Results. The data correlate changes in the measured dielectric properties to surface and bulk changes as the composite is exposed to an ethanol: DI mixture (75% ethanol). A model for the system is presented, as are future plans to simplify the methodology for rapid materials screening and in vitro analyses. Significance. This in situ diagnostic chip will enable evaluation of composite specimens, tested under a wide range of simulated oral environments. It may also serve as a screening platform for new composite formulations and aid in the study of materials degradation and failure mechanisms. (C) 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.