A self-adaptive fluidic probe for electrical caries detection

This paper presents a miniature fluidic probe that is capable of self-adapting its shape to teeth and cooperating with electrical devices to detect dental caries by sensing the variation in electrical- impedance. The fluidic probe, whose liquid tip spontaneously spreads on hydrophilic tooth surface and into underlying caries, is employed to create intimate electrical contact for impedance sensing. A tubular air sleeve shaped by the probe casing is applied around the liquid tip to insulate it from surrounding saliva, and to regulate its spreading. In addition, a friction damper is integrated to stabilize the actuation of fluidic probe. In the prototype demonstration, un-restored, extracted premolar teeth were investigated and the results indicated >20-fold impedance differences between sound and carious teeth, by which caries could be identified in a consistent manner. Furthermore, the fluidic probe has been applied to detect approximal caries, which locates in the contacting surfaces of two adjacent teeth and is difficult to detect by most available schemes. As such, the proposed self-adaptive fluidic probe could readily serve as a diagnostic tool, which is critical to caries prevention and various dental-care applications.