Microleakage in overflared root canals restored with different fiber reinforced dowels

This study evaluated microleakage in overflared root canals restored with four different types of adhesively-luted fiber-reinforced dowels: DT Light Post (LP), Glassix (GL), Ribbond (RB) and StickTech Post (ST). Forty non-carious, single-rooted mandibular human premolars with straight root canals were prepared using a step-back technique and obturated with gutta-percha using lateral condensation. The restored roots were randomly divided into four groups (n=10). The root canals were overprepared, creating an overflared dowel space, and each dowel was adhesively luted using a total-etched adhesive (Single Bond) and dual-polymerizing luting agent (RelyX ARC). All specimens were thermal cycled 1000 times between 5 degrees C and 55 degrees C and stored in 2% methylene-blue solution for one week. The teeth were cut horizontally into three consecutive sections: apical (A), middle (M) and coronal (C). Each section was digitally photographed from the occlusal direction under a stereomicroscope. The images were transferred to a PC and stored in TIFF format. For each image, dye penetration was estimated as the ratio of methylene-blue-infiltrated surface divided by total dentin surfaces. The data were compared and statistically analyzed using the Kruskal-Wallis test (p