2.2.6. Post-and-Core Cementation

Resin luting cement, Rely X Unicem resin cement (3M ESPE; Seefeld, Germany), was used to cement all post and cores. The cement was mixed according to the manufacturer's instructions and was coated on the post. Cement was also applied into the root canals by attaching an elongation tip to the nozzle. After that, posts were gently inserted into the root canals to reduce the hydrostatic pressure; they were positioned in place under firm finger pressure, and excess cement was removed (Figure 6). Then, specimens of each group (*n* = 20) were kept in normal saline for 24 h in a refrigerator before testing. Thermocycling (Thermocycling test apparatus; Durant) was performed for all specimens in 2 water tanks (cold, warm) by immersion at the temperatures of 5 ◦C and 55 ◦C and fixed time intervals (16 s cold, 16 s warm) for a total of 6000 cycles, which represented 7 months of clinical use [41].
