Fracture Strength Of Fiber-Reinforced Post And Core Anterior Restorations

Objectives: The aim of this in vitro-study was to investigate the influence of core material, post length, type of bonding and cement on the fracture strength of a glass-fibre reinforced composite post for anterior restorations.

Materials and methods: 48 human upper incisors were embedded in PMMA blocks at an angle of 135°. An artificial periodontium was simulated by a thin layer of silicone impression material. All teeth were randomly divided into 6 groups with varying core material, post length and cementation. Post/Core/Cement-Bonding: I) without post/Tetric Ceram/Variolink II-Syntac (Ivoclar-Vivadent, Schaan, FL), II) Postec/Tetric Ceram/Variolink II-Syntac (Ivoclar-Vivadent, Schaan, FL), III) Postec/Tetric Ceram/Rely X Unicem (Ivoclar-Vivadent, Schaan, FL and 3M Espe, Seefeld, G), IV) Postec/Rebilda/Variolink II-Syntac (Ivoclar-Vivadent, Schaan, FL and VOCO, Cuxhaven, G), V) Postec 5mm/Tetric Ceram/Variolink II-Syntac (Ivoclar-Vivadent, Schaan, FL), VI) Postec/Coradent/Variolink II-Adhese (Ivoclar-Vivadent, Schaan, FL). Identical designed composite cores and all-ceramic crowns (Empress 2, Ivoclar-Vivadent, Schaan, FL) were provided. Posts, cores and crowns were adhesively fixed as described. 8 specimens per group were stressed in an artificial mouth environment to simulate 5 years of clinical service (TCML 6000x5°C/55°C, each 2min, 1.2*10⁶ x 50N). After TCML the fracture resistance was determined (v=1mm/min, 135°, Zwick 1446, G). Statistical analysis was performed using the Mann Whitney U-test (p=0.05).

Results:

Conclusions: The fracture strength of fibre-reinforced post and core restorations is dependent on the core material and use of a post. An influence of the cementation and length of the post could not be found.