Bond strength of cemented fiber posts to teeth with simulated internal root resorption.

R Abreu,Ao Dal Piva,C Pucci,A Abu-Hasna,Ts Santos,C Torres,C Carvalho,J Monteiro

doi:10.4317/jced.56568

Abstract

BackgroundTeeth with internal root resorption (IRR) have guarded prognosis, considering that IRR defect could influence on the post bond strength. The aim of this study was to evaluate the bond strength and the bond interface between different glass fiber-reinforced posts (FRP) after cementation in teeth with simulated internal root resorption (IRR). Material and MethodsForty-five (45) human premolar roots with simulated IRR were embedded in acrylic resin blocks and cross-sectioned into two segments, enabling them to be re-approximated by screws. Intracanal medication was inserted for 15-days, removed by passive ultrasonic irrigation (PUI) and examined by stereomicroscopy. The push-out bond strength of two fiber reinforced composite posts (Rebilda Post - RP) and Rebilda Post GT – GT, (VOCO) were evaluated at the cervical and IRR regions (n = 20). And, the bonded interface between resin cement and root dentine was analysed by scanning electron microscopy (SEM). Results62.5% of IRR were not completely cleaned by PUI. Bond strength values at the cervical region (9.8 and 14.6 MPa) were higher than the IRR region (6.3 and 4.2 MPa). Micrographies showed bubbles in the cement and spaces in the bonded interface. ConclusionsRP post showed better bond strength at the cervical region while GT had better bond strength at the IRR region. Key words:Endodontics, root canal filling materials, root resorption, X-Ray microtomography.

Highlights

Root canal treatment is the indicated approach for internal root resorption (IRR) when the affected teeth is restorable and have a reasonable prognosis [1]
The IRR promotes defects that usually renders the unachievement of a complete bio-mechanical preparation; since, some parts of the lesion remain untouched during canal instrumentation and require adjunctive chemical debridement techniques, such as, passive ultrasonic irrigation (PUI) to improve the effectiveness of the root canal irrigants [6]
GT post still has some questions that have not been answered in the literature, such as if its use could influence on the integrity of the bonded interface between the resin cement and root dentine after cementation

Summary

Introduction

Root canal treatment is the indicated approach for internal root resorption (IRR) when the affected teeth is restorable and have a reasonable prognosis [1]. -Fiber post cementation The upper and lower portions of each specimen were bonded with cyanoacrylate glue (Super Bonder, Loctite, São Paulo, Brazil) at the inner edges of the acrylic resin of each portion, guided by the position of the screws for re-approximation of the root to its original position. -Micro-CT and 3D reconstruction Three specimens from GT group were evaluated by micro-CT (Skyscan model 1176, Kontich, Belgium) to investigate the disposition of the posts, cementation line defects and possible interference of remnants during the root canal treatment. Under axial and longitudinal sections it was possible to identify failures in the resin cement as unfilled spaces and bubbles in root canal, mainly in isthmus regions and, in larger numbers within the IRR simulated defect

Discussion

Findings

Conclusions