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Effectiveness of preparation guidelines for an all-ceramic restorative system
Catherine C Begazo1, Jef M van der Zel, Marinius A J van Waas
1Department of Oral Function, Academic Center of Dentistry Amsterdam, University of Amsterdam, The Netherlands. dental.materials@acta.nl
Purpose:
To evaluate, in a clinical field-test, the implementation of manufacturer's preparation guidelines for the all-ceramic CICERO system.
Methods:
General dental practitioners from the northwest region of The Netherlands were asked to make complete crown preparations in accordance with the specific guidelines of the CICERO system. 3,446 tooth preparations were evaluated with regard to shoulder angle, shoulder width and top angle. They were quantified using a special software program. The results were compared with criteria defined in the manufacturer's preparation guidelines.
Results:
On a multivariate level all (main and interaction) effects were significant (P < 0.05) excluding the interaction effect of the location of measurement on the tooth by the upper or lower jaw. The value of the shoulder angle showed a strong relation with the tooth position in the mouth as well as with the location of measurement on the tooth. The shoulder width in the lower jaw was significantly smaller when compared to the width in the upper jaw. The shoulder width of the lower incisors was the smallest and also showed the largest variance per tooth. On a group level (incisor, cuspid, premolar, molar), except for the shoulder width of the lower incisors, the average values of all preparation parameters were within the borders as defined in the preparation guidelines of the manufacturer. However, on an individual tooth level nearly all preparations showed to have one or more locations with imperfections.