Effect of mechanical cleaning protocols in the fiber post space on the adhesive interface between universal adhesive and root dentin

Abstract

The aim of this study was to evaluate the effects of cleaning protocols on the presence of residues, open dentinal tubules, and bond strength of a self-etch adhesive plus a dual-cure resin cement to dentin in the fiber-post space. The methods for cleaning utilized were conventional irrigation (CI), rotary brush with continuous rotary movement (RB), and continuous ultrasonic irrigation (CUI). Sixty bovine incisors were used for fiber-post space preparation. Thirty roots were divided into three groups (n = 10) according to the cleaning protocols and submitted to scanning electron microscope to evaluate presence of residues and relative quantity of open dentinal tubules on dentin surface. Similar protocols were performed in the other thirty roots (n = 10) using a self-etching adhesive system (Scotchbond Universal) and a dual-cure resin cement (Relyx Unicem 2). After 6 months cervical, middle, and apical thirds sections of fiber-post space were submitted to push-out testing. To data ANOVA and Tukey's test were employed (α = 5%). RB and CUI showed the lowest presence of residues on dentin surface (p = .015) and the highest bond strength values (p < .001), regardless of the dentin third. CUI presented the highest quantity of open dentinal tubules in middle and apical thirds (p < .001). CI presented the lowest bond strength value of resin cement, regardless of dentin third (p < .001).Mechanical cleaning protocols, such as RB and CUI, presented better surface cleaning capabilities and higher bond strength than CI with dual-cure resin cement employed.The use of a mechanical cleaning protocol seems to cause appropriate condition on the root dentin surface. Mechanical cleaning of root dentin provided greater bond strength of the self-etching system with dual resin cement. Conventional irrigation did not provide adequate root dentin cleaning.

Evaluation of different mechanical cleaning protocols associated with 2.5% sodium hypochlorite in the removal of residues from the post space

“…This study demonstrated that the protocols combining mechanical and chemical residue cleaning have the same effect, contrary to findings from previous studies. [ 17 18 19 20 ] However, it is worth mentioning that discrepancies may arise from the different experimental designs used, such as the activation of the irrigant, suggesting that this protocol enables a more effective flow of the solution, enhancing its action. [ 18 ] In addition, it is important to note that, despite NaOCl being a preferred chemical cleaning agent for root canal disinfection, its effectiveness in removing the smear layer is reported to be limited when applied alone.…”

Formulations of NaOCl-based in liquid, gel form or with surfactants on dentin deproteinization before fiber post cementation

“…Furthermore, no significant differences were observed in bond strength in the apical thirds following the deproteinization protocols with DWC, SHS, and SHT. The apical region, due to its greater difficulty in cleaning, tends to have a higher amount of debris resulting from the preparation of the post space, which hinders access and impairs the flow of the cementing material 41) . Additionally, the presence of numerous accessory canals reduces the available surface area for the adhesion process 42,43) .…”

“…This difference can be attributed to the viscosity of the irrigant, which led to less debris removal in the deeper portions of the post space. This reduction in debris cleaning may have compromised the cement penetration and consequently resulted in a lower extension of resin tags 41) .…”

Evaluation of bond strength in customizing fiber post using translucent resins photoactivated by different light-emitting diodes

“…[ 6 ] Currently, what has been observed in the literature are investigations of different methods of cleaning residues in the postspace resistance of the post, cement, and dentin assembly. [ 7 8 9 10 11 12 13 ] Evaluations of different resinous materials, specifically translucent resins for postcustomization, are still not extensively addressed. Therefore, the authors were encouraged to conduct this in vitro assay in an attempt to investigate whether the translucency of different resins influences the bond strength and adhesive failure pattern.…”