Abstract: A dental instrument including a shaft having firmly attached at one end thereof a mirror which is carried by a housing provided with an inlet opening to a first internal channel which communicates with a channel provided in the shaft, this latter channel being intended for connection to a suction source. According to the invention the shaft (17) incorporates a second channel (16) having one end which opens above the mirror (2) and the other end of which is intended for connection to a pressurized-air source via a control means (23) effective to regulate the supply of pressurized air to a turbine drill, whereby the supply of pressurized air to the instrument (1) is proportional to the supply of pressurized air to the turbine drill, and whereby the pressurized air supplied to the instrument (1) is blown over the mirror (2).