The dental device for insertion of a crown is a tool for marking an occlusally reduced tooth prior to application of a crown thereon, and for testing whether the tooth has been sufficiently reduced for proper application of the crown. The dental device includes a marking portion frangibly joined to a resistance testing portion. The marking portion includes a marking layer formed of a transferable material so that, following occlusal reduction of the tooth, the marking portion is separated from the resistance testing portion, and the marking layer is positioned against an upper surface of the tooth. The patient bites down on the marking layer to mark raised regions of the upper surface of the tooth, and subsequently bites down on the resistance testing portion, to test if the tooth has been sufficiently reduced for application of a crown thereon.