Retaining device for a dental workpiece

A retaining device for retaining a disk-shaped dental workpiece, the retaining device comprising:

• a retaining ring having a central axis and configured to receive the dental workpiece, and
• a clamping device configured to clamp the dental workpiece to the retaining ring, the clamping device including:
• a supporting surface for supporting the dental workpiece, the supporting surface being mounted or formed on the retaining ring and projecting radially in the direction of the central axis, and
• a clamping element mounted moveably on the retaining ring, the clamping device being configured to clamp the dental workpiece between the clamping element and the supporting surface in a clamping position,
• wherein the retaining ring includes:
• an inner ring element having a circular inner space defined by a circular inner surface on which the supporting surface is mounted or formed, and the clamping element is moveably mounted on the inner ring element, the workpiece to be mounted within the circular inner space of the inner ring element so as to be clamped between the clamping element and the supporting surface,
• an outer ring element in which the inner ring element is to be mounted, and
• a fixing device configured to releasably fix the inner ring element to the outer ring element, the fixing device including:
• a plurality of supporting elements spaced apart uniformly around the central axis and uniformly spaced from the central axis and arranged on the outer ring element,
• a plurality of counterpart supporting portions spaced apart uniformly around the central axis and spaced uniformly from the central axis and arranged on the inner ring element so as to correspond to the plurality of supporting elements, and
• a plurality of fixing elements mounted movably on and spaced apart uniformly on the outer ring element such that, in a fixing position, the inner ring element is fixed between the fixing elements and the supporting elements,
• wherein the fixing device is configured to, upon removal of the inner ring element from the outer ring element, ensure the inner ring element is re-fittable into the outer ring element in the same exact position relative to the outer ring element as before removal of the inner ring element.