Effect of EDTA and silane on the bond strength of cementing agents of glass fiber posts to root dentin.

Background: This study aimed to evaluate the effect of dentin pre-treatment with EDTA and silanization of glass fiber posts on the bond strength of different resin cements to root dentin.

Material and methods: Fifty-six extracted single-rooted human teeth received endodontic treatment and were restored with White Post DC (FGM) 0.5 fiber posts. Samples were divided into four groups: (1) Relyx U200 without EDTA, (2) Relyx U200 with EDTA, (3) Relyx ARC without EDTA, and (4) Relyx ARC with EDTA. Each group had a silane-treated subgroup (n=7). Root canals were prepared with Peeso reamer No. 3, leaving 4 mm of filling. Posts were cleaned with absolute alcohol (1 min) and air-dried (30 s). Silane was applied to half the posts for 60 s, then air-dried for 30 s. Specimens were mounted on acrylic plates with low-melting adhesive and sectioned using an Isomet saw (200 rpm, constant irrigation) and extra-fine diamond disc. Three slices (~1.5 mm thick) were obtained per tooth (coronal, middle, apical thirds). Thickness was measured with a digital caliper. Slices were positioned cervical side down in a 3.5 mm support matrix. A force was applied at 0.5 mm/min using a rod with a 0.8 mm extra-fine tip. Data were analyzed using Kolmogorov-Smirnov and Student's t-tests.

Results: Relyx ARC showed higher bond strength than Relyx U200, regardless of silane or EDTA use. The combination of silane and EDTA did not significantly affect results (Relyx U200 p=0.402; Relyx ARC p=0.510). Adhesive failure at the cement/dentin interface occurred in 51.61% of all samples, regardless of technique.

Conclusions: EDTA and/or silane did not influence the bond strength of fiber posts to root dentin. Key words:Bond Strength, Edetic Acid, Fiber-posts, Endodontics.