Abstract: A rotary cutting tool for the reception in a dental drill and use in preparing a tooth stump for the mounting of a tooth crown has a frustoconical cavity and a frustoconical lateral exterior surface. The exterior surface shape facilitates manipulation of the tool by the dentist and the interior shape is covered with abrasive matter that, in use of the tool, serves to shape both the top and the lateral surfaces of the tooth stump spike. At the base of the tool, an annular, abrasive coated surface is provided to shape the tooth stump and provide a ledge in those situations where the spike is to receive a full crown. Adjacent the annular surface, the lateral exterior surface may be coated with water repellent material that serves to protect adjacent teeth from damage and to also minimize gum damage when gum penetration occurs.