A dental syringe may include a replaceable valve cartridge containing one or more valves. A packing seal is disposed between a shoulder formed on an inner wall of a housing of the sensor body and a tapered surface of an insulation porcelain installed in the housing to define the gas chamber and the reference gas chamber hermetically. Therefrom the user selects an operation that the user desires to execute for the selected file. Detection of the first data bit is accomplished by selectively applying a read bias to the FET terminals, a first current resulting when a first state is stored and a second current resulting when a second state is stored. In doing so, it has been found that the haze of the article can be substantially masked.