The device includes a shim component constructed for use in the non-surgical treatment of interproximal carious dental lesions. A plunger may be provided for driving substances through a tube-like channel or bore in the shim component, or an electromagnetic energy-transmissive material may fill the channel, in either case for delivering to the site of the lesion a medium that is effective for directly or indirectly killing, or biologically damaging, the carious bacteria.