Accuracy of scannable bite registration materials by using the CEREC 3D system

The fabrication of full-ceramic-restorations with the Cerec 3D® System (Sirona Dental Systems GmbH, Bensheim) includes the option to consider the occlusal surfaces of the antagonistic teeth in the construction by scanning an interocclusal record. Thereby extensive occlusal adjustments in the patient should be cancelled. The objective of the study was to determine how exactly the interocclusal record passes information to the Cerec 3D® system. The exactness was examined for the simulated clinical situation in mouth as well as the lab situation on gypsum models. Nine scannable materials of different manufacturers were measured in comparison among each other and in comparison to a primarily not scannable material whose surface was conditioned. The interocclusal records were made in stylised antagonistic casts which were mounted in an articulator to simulate the oral situation. These models were measured at first mechanically. The records were evaluated with the Cerec 3D® internal height data. By using a specially developed algorithm (considered the mechanically won data) the precision was calculated. Different proceedings in the production and measurement of the records were executed. The most exact procedure for the simulation of the chairside-treatment is characterised by very low manipulations on the interocclusal record. Trimming the record should be done in situ without demounting from the teeth. Conditioning the neighbouring teeth with scan spray should be extended also on the surface of the record in one step. Thereby the measured divergences to the surface of the original model amount from 1 to 14 µm on average, according to recording material. However, the vertical discrepancies increased between 36 and 98 µm on average when using the interocclusal record on gypsum models. Keywords: accuracy, scannable, cerec, bite registration, interocclusal recording