A sensing circuit for use with a CAM circuit including multiple match lines and multiple CAM cells connected to the match lines includes at least one charge sharing circuit and at least one switching circuit connected to the charge sharing circuit. The representation of the current arrangement may be, for example, a physical impression of the subject’s teeth, a 3D scan or one or more 2D scans of the subject’s teeth. The body includes an incident surface to which light is incident and an emitting surface from which the incident light is emitted.