A dental turbine driven by pressurized air comprises a head housing (1) with a turbine chamber (2) and a rotor shaft (3) mounted using an anti-friction bearing (8a) with a non-rotatably mounted turbine wheel (13). The outer race (10a) of the anti-friction bearing (8a) extends into the turbine chamber (2) in axial direction. The turbine wheel (13) comprises an annular web (16a) that is arranged concentrically to the outer race (10a) of the anti-friction bearing (8a) and, together with the outer race (10a), forms a gap seal (17a). This gap seal (17a) extends in axial direction between outer race (10a) and annular web (16a) and prevents the sucking-in of liquids and dirt particles into the turbine chamber (2) during inertial rotation of the turbine wheel (13).