dental materials 25 ( 2 0 0 9 ) 348–352 available at www.sciencedirect.com journal homepage: www.intl.elsevierhealth.com/journals/dema Approach for valuating the influence of laboratory simulation Martin Rosentritt a,* , Michael Behr a , Jef M. van der Zel b , Albert J. Feilzer b a Department of Prosthetic Dentistry, Regensburg University Medical Center, Regensburg D-93042, Germany b Department of Dental Materials Science, Academic Centre for Dentistry, Universiteit van Amsterdam and Vrije Universiteit, The Netherlands article info Article history: Received 18 April 2007 Received in revised form 1 August 2008 Accepted 7 August 2008 Keywords: Simulation Survival rate TCML CAD/CAM abstract Objective. The aim of this investigation was to determine the fracture resistance of zirconia fixed partial dentures (FPDs) after laboratory simulation. Failure type and failure rates during simulation were compared to available clinical data for estimating the relevance of the simulation. Methods. 32 FPDs were fabricated of a zirconia ceramic and a corresponding ceramic veneer. The FPDs were adhesively bonded on human molars and artificial aging was performed for investigating the survival rate during thermal cycling and mechanical loading (TCML1; 3.6 Mio × 50N ML). Survival rates were compared to available clinical data and the TCML parameter “mastication force” was adapted accordingly for a second TCML run (TCML2; 3.6 Mio × 100N ML). The fracture resistance of the FPDs which survived TCML was deter- mined. FPDs were examined without TCML (control) or after TCML according to literature (1.2 Mio × 50 N ML). Data were statistically analyzed (Mann–Whitney U-test) and curve fit- ting/regression analysis of the survival rates was performed. Results. TCML reduced survival rates down to 63%. Failures during TCML were chipping off of the veneering ceramic, no zirconia framework was damaged. Under clinical conditions comparable failures (chipping) are reported. The clinical survival rate (∼10%) is lower com- pared to TCML data because of the short period of observation. The fracture resistance after TCML was significantly reduced from 1058 N (control) to values between 320 and 533 N. Conclusion. The results indicate that TCML with 1.2 Mio × 50 N provides a sufficient explanatory power. TCML with prolonged simulation time may allow the definition of a mathematical model for estimating future survival rates. © 2008 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved. 1. Introduction A clinical trial is the first choice for evaluating the effect of medical treatment or usability of new materials. The results of significant clinical investigations are often restricted by high investments and expenditure, sometimes combined with low outcome due to a small number of subjects or high devia- ∗ Corresponding author. Tel.: +49 941 944 6054; fax: +49 941 944 6171. E-mail address: Martin.Rosentritt@klinik.uni-regensburg.de (M. Rosentritt). tions of the results [1]. Therefore, in vitro simulations become more and more important for time-lapsed testing of new materials in advance. In times of the ephemerality of dental materials, computer controlled (Finite Element Analysis) [2], or laboratory simulations were used for pre-clinical investi- gations of materials or restorations, trying to predict at least catastrophic failures [3]. Various systems for simulating the 0109-5641/$ – see front matter © 2008 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.dental.2008.08.009