Medical device (1), particularly dental, for determining the quality of a bone by means of styling a thread in the bone by means of a rotary thread element (3) with at least one edge, the medical device (1) comprising, particularly dental, a control device (2) having a first electrical contact device (2A) for connecting to a motor drive (5), a second contact device (2B) for connecting to an indicator unit (4) and a measuring circuit (6) that is operatively connected to the first electrical contact device (2A) and the second contact device (2B), the measuring circuit (6) being formed to: (i) by the first device (2A) of electrical contact determine values of the motor current, with which the drive (5) by motor is supplied to rotatably drive the thread element (3) that can be attached to the drive (5) by motor, the values of ran The motor correlated with, or being essentially proportional to, transmitted torque values of the drive (5) per motor and the motor current values or torque values being a measure of the quality of a bone, (ii) monitor and / or check the penetration depth of the thread element (3) in the bone, and (iii) generate measurement signals that relate the determined motor current values, the torque values correlated with the motor current values or essentially proportional to them or the quality of a bone derived from the determined motor current values or the torque values with the penetration depth, and transmit those measurement signals to the indicating unit (4) by the second device (2B ) of contact, so that the indicator unit (4) reproduces on the basis of the transmitted measurement signals the relationship between the penetration depth and at least one of the following These parameters, namely the determined motor current values, the torque values correlated with the motor current values or essentially proportional to them or the quality of a bone, characterized in that the control device (2) is formed not to start monitoring, checking or record
