Abstract: A dental unit capable of positioning dental instruments at a location convenient to either a seated or standing dentist. The unit has the instrument holder mounted on a four-bar linkage for swinging the holder from a relatively low stored position to an in-use position. At a low point of the swing, the dental instruments are at a relatively low position and convenient to a seated dentist. The four-bar linkage is arranged so that at a higher point in the swing, the instrument holder is thrust to a relatively high position as may be convenient to a standing dentist.