Pullout resistance tests
The remaining 15 samples from each group (30 pieces) were placed and fixed tightly in custom apparatus to prevent movement during testing. The custom apparatus was selected for the lower arm of the universal testing machine that allowed the posts to be positioned vertically. In contrast, the core was fitted to dynamometer clamps of the upper arm of the device. The pullout test was performed parallel to the long axis of the post at a crosshead speed of 1.0 mm/min in a universal testing machine. The maximum force required to dislodge each post was recorded in Newton (N).