A method and a device for the evaluation of the retention of telescopic dental crowns

Telescopic crowns are used as support for removable dental prostheses' construction. A distinctive feature of crowns often used in their description and comparison is retention, which is understood as resistance when removing the prosthesis or a force needed to disconnect crowns. The article describes a method for the evaluation of retention in simulated conditions using a dedicated testing device. By subjecting the crown to cyclic loads in the range of forces occurring during clinical use and in the range of cycles leading to visible effects of wear, the method provides the evaluation of crowns in a wide range of duration, up to the loss of functionality. It also facilitates the identification of dominant phases of crown behaviour, which may be correlated with the results of clinical trials.