Effect of formula, pressing technique, and location within the block on mechanical properties of dental zirconia

Abstract

Statement of problem: Different chemical formulations, pressing techniques and sintering protocoIs have been applied to manufacture zirconia-based ceramic core materials. Little is known about the effect of each one of those variables on the strength of Y-TZP material. Most of the preVious studies compared the strength of different Y-TZP materials and the effects of sintering protocoIs, pressing techniques, aging, and surface treatment. The mechanical effects of the location within the Y-TZP block where the bar originates were not reported. 0bjectives: The aim of this study was to test the flexural strength of 9 different Y-TZP core ceramic materials and investigate the effects of chemical formulations, pressing techniques, and location within the block where the bar originated on the flexural strength. Materials and Methods: Nine zirconia-based core ceramic materials were tested (Table 1). 12 different types of blocks were fabricated out of these 9 materials with different chemical formulations and pressing techniques. Two experimental blocks XU and XC were pressed and partially sintered at Boston University. The two experimental and 5 commercially available blocks K (Kavo), I (Sirona), YZ (Vita), AU and AC (GC) were sectioned to fabricate bar-shaped specimens approximately 25x3x2 mm in dimensions after full sintering at Boston University. 5 groups of bars fabricated by Glidewell GCZ1, GCZ2, GCZ3, GD and GL with 44x4x3 mm dimensions were received fully sintered, polished and had beveled edges. [TRUNCATED]