M. ROSENTRITT*, M. BEHR, R. LANG, S. KLEINMAYER, G. HANDEL.
(Department of Prosthetic Dentistry, University of Regensburg, Germany)
The aim of this in-vitro study was to determine the fracture strength of adhesively luted tooth colored fixed partial dentures (FPD). 64 human molars were inserted in PMMA resin to simulate three-unit (10mm) oral situation. The roots of the teeth were covered with an about 1mm thick layer of polyether to simulate the periodontium. 8 bridges of each series were made of A) Inceram (Vita, G), B) Empress2 (Ivoclar, FL), C) CAD/CAM Lava (Espe, G) and D) exper. design of fiber-reinforced composite and ceramic (Vectris-Empress2, Ivoclar, FL). After thermal cycling and mechanical loading (TCML; 6000 thermal cycles [5°C/55°C], 1.2x106 mastication cycles [50N]) fracture strengths (UTM 1446; Zwick; v=1mm/min) of 8 FPDs of each series were determined. Statistics: One-Way-ANOVA (p=0.05).
In comparison to Lava and exp. FPDs the Inceram and Empress2 restorations showed significantly lower fracture strength values. No differences could be found between Empress2 and Inceram, and between Lava and exp. Design. The fracture values are located at a limit where clinical application seems promising. This study was supported by ESPE, Germany.