Adhesion of bulk-fill resin composites as core and intraradicular post materials only versus the use of glass-fiber posts in different regions of root dentin

Abstract

This study assessed adhesion of bulk-fill resin-composites as core and post materials only versus the use of fiber resin composite (FRC) posts. Human teeth (N = 84) were cut at the CEJ and endodontically treated and randomly divided into seven groups: TP: Titanium post (Flat Head T); SFRC: S2-glass FRC (Pinpost); EFRC1: E-glass FRC (GC Everstick) directly bonded; GFRC: E-glass FRC (Glassix Nordin); EFRC2: E-glass FRC (Everstick); BF1: Bulk-fill resin (Surefill SDR); BF2: Bulk-fill resin (SonicFill). Groups TP, SFRC, EFRC and GFRC were cemented (Panavia 21), while other groups were bonded directly to the intraradicular dentin. The core parts were constructed using a resin composite (G-aenial) except for Groups BF1 and BF2. The core-cervical dentin interface was loaded under shear forces. Push-out tests were performed in a Universal Testing Machine (1 mm/min). Data (MPa) were analyzed using two-way ANOVA and Tukey's tests (= 0.05). Not the root level (p > 0.05) but the type of core and post material significantly affected shear and push-out bond results (p < 0.001). BF1 (9.2 ± 2.1) and BF2 (9.3 ± 3.1) showed significantly lower bond strength to the cervical dentin (p < 0.05) compared to other groups (11.6 ± 2.5-19 ± 6.8). FRC post types did not show significant difference being higher than those of TP, BF1 and BF2 (0.57 ± 0.37-2.34 ± 1.98) (p > 0.05). Partial cohesive core fracture was more common while BF1 and BF2 showed exclusively adhesive failures. Cohesive failure in the cement was frequent in Group TP (53%) compared to other groups (3-24%). BF1 and BF2 presented exclusively complete adhesive failure of the bulk-fill material.

Can fiber-reinforced resin composites alone substitute adhesively luted intraradicular post and core materials under static and dynamic loading?

“…Ethical guidelines were strictly followed and irreversible anonymization was performed in accordance with State and Federal Law [21][22][23]. After tissue remnants were removed with a scaler (H6/H7; Hu-Friedy, Chicago, IL), teeth were stored in 0.5% Chloramin T for 4 weeks [24]. The roots of the teeth were embedded until the cement-enamel junction (CEJ) in a polyvinyl chloride (PVC) mould using auto-polymerizing acrylic resin (Scandiquick, Scandia, Hagen, Germany).…”

“…The roots were mounted in a parallelometer (Type PFG 100, Cendres & M etaux, Biel, Switzerland) and the canals were prepared up to a diameter of 1.35 mm with a working length of 8 mm until the apical foramen using a standard drill (FRC Postec Reamer, Ivoclar Vivadent, Schaan, Liechtenstein). The teeth were randomly divided into six groups having a mean root length of 12 mm simulating the endodontic treatment as described elsewhere [24]. Each canal and post were threatened according to the manufacturer's instructions.…”