Effect of 1-piece post and core fabrication techniques on fracture strength

Abstract

Purpose: The purpose of this in vitro study was to evaluate and compare the fracture strengths of post and core systems produced with different fabrication techniques and materials. Methods: Forty extracted human single-root premolars were used in this study. After root canal treatment, the teeth were randomly divided into 4 groups of 10 each as follows: group C: metallic 1-piece posts and cores fabricated by casting, and serving as the control; group CM: metallic posts and cores fabricated with the copy milled technique; group LS: 1-piece posts and cores fabricated with the laser sintering technique; and group ZR: 1-piece zirconia posts and cores fabricated with computer-aided design and computer-aided manufacturing (CAD-CAM). The posts and cores were cemented to the teeth with adhesive resin cement; then, the specimens were mounted to acrylic resin blocks, attached to an Instron Universal Testing Machine, and loaded with a crosshead speed of 1 mm/min, until fracture. Data were statistically analyzed using 1-way analysis of variance (ANOVA), followed by the post hoc Tukey test (alpha = 0.05). Results: The highest fracture results were found in group ZR (315.4 +/- 53.4 N), which showed significant differences from all other groups (p<0.05). The lowest test values were found in group C (230.2 +/- 29.8 N). Group LS (250.9 +/- 29.0 N), group CM (253.0 +/- 22.4 N) and group C did not show any significant differences (p>0.05). Conclusions: Custom-made zirconia 1-piece posts and cores, fabricated using the CAD-CAM procedure, can be an alternative treatment method when compared with other techniques.