One Step Beyond or One Step Debond?

A patient has returned to your practice, complaining about the debonded fibre-reinforced composite post. ‘Not again!’ you think, vexed at the failure. Bonding materials within the root canal has always been challenging. You wonder which bonding system you should use to reduce the risk of post delamination in the future. Well, hopefully, this research performed by Fereshteh Shafiei, Pourya Mohammadparast and Zahra Jowkar can provide you some guidance!

In this study, fifty-six root treated maxillary central incisors have been assessed. Based on the irrigant/adhesive protocol used for post cementation, the roots were divided into seven groups. Push-out tests were performed and the debonded specimens were analysed. Adhesive interfaces were evaluated under scanning electron microscope (SEM).

Results suggest that bonding strength of a material can be hugely affected by the adhesive approach and type of irrigant utilized. Etch-and-rinse (ER) adhesive system works well when the smear layer is removed. It is found to be effective when the post space was prepared by 1% sodium hypochlorite (NaOCl) with passive ultrasonic irrigation, accompanied by distilled water irrigation. The self-etch (SE) system, on the other hand, simplifies the technique sensitive bonding procedures. However, with its relatively low acidity of pH 3.2, the permeation ability of it through a thick smear layer is questionable. Therefore, the use of post space irrigant is recommended. Beware the performance of SE system is dependent on irrigant used. EDTA prepared root spaces have higher adhesive effects compared to NaOCl. This may be due to NaOCl’s inability to remove the smear layer.

According to the collected data, the coronal root region has the highest bonding strength, followed by the middle region and the apical region. Regardless of region, roots with post space prepared by EDTA, cemented using All-Bond Universal (ABU) SE system has shown a significantly higher bonding strength than the other groups. Contrarily, the combination of NaOCl and ABU SE system has the lowest bonding strength. It is also the only group that indicates no signs of resin tag formation when observed under SEM.