A medical or dental instrument part having a coupling device for connecting the instrument part to a control, regulating or supply unit, a memory device that can be operated with electrical power for storing identification data and/or operating and/or care data of the instrument part and at least one electrical line, which is provided for supplying electrical power to a lighting device that is provided on the instrument part or can be connected to the instrument part for operating the lighting device and for supplying electrical power to the memory device for operating the memory device. In addition, a medical or dental treatment device having such a medical or dental instrument part and a corresponding method for supplying electrical power to a lighting device and to a memory device by at least one electrical line are provided.
