The physical principle involved has nothing to do with friction in the conventional sense. Gauging the friction made fabrication of telescope restorations difficult using the standard casting technique. Too many variables, including waxing up, investment and casting, were involved. An undesirable consequence was the relatively unreliable long-term success, i.e. patients complained that their restoration was too loose or that they had problems inserting or removing it.

All that is now a thing of the past with HELIOFORM^® telescope crowns, as their function is based on a completely different principle. The best and simpliest way of describing the function is to imagine the effect of placing two glass plates together with a little water between them. The plates can be slid against one another, but they cannot be pulled apart. The thin film of liquid at the interface of the two glass plates forms an adhesive force that is not easily broken. Primary and secondary crowns with a film of saliva between them behave in the same way. This is only possible due to the excellent fit of electroformed secondary crowns.

The HELIOFORM^® electroforming technique electroforms directly onto the milled, polished primary crown without any transfer procedure. With titanium and non-precious metal primary crowns the conductive silver lacquer application can even be omitted, though the conductive lacquer is required for gold and porcelain. A special airbrush technique can now be used to apply a very thin, uniform film of conductive lacquer so that there is no adverse effect on the final restoration. According to WEIGL, the bonding force is in a range of 6 – 10 N, the same as a physiological force. Patients report that the restoration is comfortable to wear because the restoration slides smoothly into its final position without any friction and is easily removed. Though it is a removable restoration, patients feel that they are wearing a fixed restoration once it is in situ.

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