Effects of Filling Technique and Light Irradiation Distance on the Push-Out Bond Strength of Dual and Light Cured Core Materials in a Direct Core Build-Up

Abstract

This study evaluated the effects of filling technique and light irradiation distance on the push-out bond strength of dual-cured (DC) and light-cured (LC) core materials to the root canal dentin. DC and LC core materials were filled with a bovine root canal post space of 8[Formula: see text]mm deep, and polymerized under two different filling procedures, i.e., an 8[Formula: see text]mm bulk filling (I) and two times of 4[Formula: see text]mm incremental filling (II), multiplying two different light irradiation distances (0 or 5[Formula: see text]mm) from top of the root canal. After 24[Formula: see text]h water storage, specimens were horizontally sectioned to obtain [Formula: see text][Formula: see text]mm thick core/dentin slices, and five slices were obtained for each root. After the slicing process, push-out tests were performed. Among all groups, the highest bond strength was observed in DCI5 (13.7 [Formula: see text] 4.3[Formula: see text]MPa), whereas the lowest was observed in LCI0 ([Formula: see text][Formula: see text]MPa). Consequently, the recommended curing procedure between DC and LC core materials differed. Combination of LC core material with incremental filling technique and of DC core material with bulk filling technique indicated higher bond strength. Higher bond strength was measured at a 5[Formula: see text]mm light irradiation distance for both LC and DC core materials.