Effect of plunger diameter on the push-out bond values of different root filling materials.

摘要

AIMS: To evaluate the effect of plunger diameter on the push-out bond strength of different root filling materials to root canal dentine. METHODOLOGY: Freshly extracted human incisors (n=90) were decoronated, and the root canals were enlarged with post drills. Prepared roots were placed into a custom alignment apparatus to embed the roots vertically within self-curing acrylic resin. The specimens were randomly assigned into three groups according to the root filling system used: gutta-percha/AH Plus; Resilon/Epiphany; and fibre-reinforced composite (FRC)/Duolink resin cement. After filling, the specimens were further subdivided according to the diameter of the plunger used to employ the debonding force: 0.75, 1 and 1.25 mm. Intra-radicular bond strength was measured using the push-out test at a cross-head speed of 1 mm min(-1) . The data were analysed statistically using Kruskal-Wallis test with Bonferroni correction at P = 0.05. RESULTS: Regardless of the plunger diameter, FRC yielded the highest bond strength, followed by gutta-percha and Resilon, respectively (P<0.001). In all groups, greater plunger diameter resulted in an apparent increased bond strength, but the differences were only significant in the FRC group, with the 1.25-mm plunger generating higher debonding values compared with that of its 0.75- and 1-mm versions (P<0.001). In the gutta-percha and Resilon groups, the majority of specimens had adhesive failures. Roots filled with FRC exhibited more cohesive failures than those of the other test groups. CONCLUSIONS: Different plunger diameters are associated with significantly different intra-radicular push-out bond strengths of root filling systems.