The dental model trimmer includes a wheel having an abrasive surface, a motor for rotating the wheel, and ultraviolet light source powerful enough to inactivate bacteria. The components are located in an enclosure that has an opening to permit access to the abrasive surface of the wheel. The light source is mounted within the enclosure to illuminate a section of the abrasive surface of the wheel that is spaced from the access opening. The enclosure includes wall means interposed between the light source and the access opening for preventing direct light emitted from the UV light source from exiting the access opening. The enclosure is provided with an interlock switch that will automatically turn off the light source when the enclosure is opened. The same switch can be used to deactivate the motor and a source of water provided to the abrasive surface, if desired.