A retaining device for an, in particular disk-shaped, dental workpiece comprising: - a retaining ring formed around a central axis for receiving the dental workpiece, and - a clamping device for clamping the dental workpiece to the retaining ring, wherein the retaining ring has - an inner ring element - an outer ring element, and - a fixing device for releasably fixing the inner ring element to the outer ring element, wherein the fixing device has at least one supporting element mounted or formed on the outer ring element, a counterpart supporting portion mounted or formed on the inner ring element and corresponding to the supporting element and at least one fixing element mounted moveably to the outer ring element, wherein in a fixing position the inner ring element can be fixed between the fixing element and the supporting element, wherein the fixing device has a plurality of, preferably three, fixing elements arranged regularly on the outer ring element, wherein each fixing element has a spindle pin mounted in the outer ring element rotatably about an axis of rotation and a fixing surface oriented substantially at a right angle to the axis of rotation and connected to the spindle pin, characterized in that the clamping device has at least one supporting surface for the dental workpiece mounted or formed on the retaining ring and projecting radially in the direction of the central axis, and at least one clamping element mounted moveably on the retaining ring, wherein in a clamping position the dental workpiece can be clamped between the at least one clamping element and the at least one supporting surface, and that on the inner ring element the at least one supporting surface is mounted or formed and the at least one clamping element is moveably mounted, and that the fixing device has a plurality of, preferably three, supporting elements which are arranged regularly around the central axis and are uniformly spaced from the central axis and arranged on the outer ring element, and a plurality of, preferably three, counterpart supporting portions which are arranged regularly around the central axis and spaced uniformly from the central axis and arranged on the inner ring element. - a retaining ring formed around a central axis for receiving the dental workpiece, and - a clamping device for clamping the dental workpiece to the retaining ring, wherein the retaining ring has - an inner ring element - an outer ring element, and - a fixing device for releasably fixing the inner ring element to the outer ring element, - an inner ring element - an outer ring element, and - a fixing device for releasably fixing the inner ring element to the outer ring element, wherein the fixing device has at least one supporting element mounted or formed on the outer ring element, a counterpart supporting portion mounted or formed on the inner ring element and corresponding to the supporting element and at least one fixing element mounted moveably to the outer ring element, wherein in a fixing position the inner ring element can be fixed between the fixing element and the supporting element, wherein the fixing device has a plurality of, preferably three, fixing elements arranged regularly on the outer ring element, wherein each fixing element has a spindle pin mounted in the outer ring element rotatably about an axis of rotation and a fixing surface oriented substantially at a right angle to the axis of rotation and connected to the spindle pin, characterized in that the clamping device has at least one supporting surface for the dental workpiece mounted or formed on the retaining ring and projecting radially in the direction of the central axis, and at least one clamping element mounted moveably on the retaining ring, wherein in a clamping position the dental workpiece can be clamped between the at least one clamping element and the at least one supporting surface, and that on the inner ring element the at least one supporting surface is mounted or formed and the at least one clamping element is moveably mounted, and that the fixing device has a plurality of, preferably three, supporting elements which are arranged regularly around the central axis and are uniformly spaced from the central axis and arranged on the outer ring element, and a plurality of, preferably three, counterpart supporting portions which are arranged regularly around the central axis and spaced uniformly from the central axis and arranged on the inner ring element.