FRACTURE RESISTANCE OF DIFFERENT ESTHETIC POST AND CORE MATERIALS AND ASSESSMENT THEIR MODE OF FAILURE

Purpose: This in vitro study measured fracture resistance of different esthetic post and core materials and compare their modes of failures.
Statement of problem: Increase esthetic demand and patient awareness have encouraged development of esthetic post and core systems. Translucency of ceramic restorations is accompanied by marked decrease in alumina content that may affect mechanical properties.
Methods:40 extracted human central incisors were used in this study. Teeth were randomly divided into 4 groups of 10 each: group 1:Translucent Zirconia(TZ);group 2:High Translucency IPS E.Max (T-IPS); group 3:Polymer Infiltrated Ceramic (Vita Enamic) (PIC) and group 4: Control group (C), teeth were endodontically treated with no posts and cores. Posts and cores were processed according to manufacturer instructions cemented to teeth with adhesive resin cement; then specimens were mounted to acrylic resin blocks, attached to Instron universal testing machine, and loaded with a crosshead speed of 0.5 mm/min, until fracture. Types of failures were also recorded in different groups. Data were statistically analyzed using 1-way analysis of variance (ANOVA), and Scheffe test made pairwise comparison (α = 0.05).
Results: TZ group showed the highest fracture resistance (454 .4±41.6 N). T-IPS showed higher results(360.4±35.7N) than PIC(300.9±35.6 N) and control(276.7±32.5 N) and the two latter groups were not significantly different from each other P Conclusions: Regarding fracture strength and mode of failure, High Translucent IPS-E Max post and core can be an alternative treatment method when compared with other techniques.