Phosphoric acid treatment enhances adaptation of glass‑ionomer cement to bioceramic sealer‑conditioned dentin

This study evaluated the interface between fresh eugenol/bioceramic sealer‑conditioned coronal dentin and high‑viscous glass‑ionomer cement (HVGIC), treated with various dentin conditioners (saline, 10% polyacrylic acid, and 37% phosphoric acid).

Standard endodontic access preparation and instrumentation were done in 21 freshly extracted mandibular molar teeth in this in vitro study. Teeth were divided into two interventional groups (n = 9/group), based on the type of sealer (zinc oxide eugenol [ZOE]/ bioceramic [BioRoot RCS] sealer) used for obturation. Samples were further subdivided based on the type of dentin‑conditioning procedures performed (saline/10% polyacrylic acid/37% phosphoric acid). Post dentin conditioning, the access cavity was sealed with HVGIC. Later, material‑dentin interfacial analysis and elemental analysis were done using scanning electron microscopy (SEM) and energy‑dispersive X‑ray spectroscopy.

The interfacial SEM images of HVGIC layered over B‑RCS/ZOE sealer‑conditioned dentin, treated with saline, showed predominantly adhesive debonding failures, whereas cohesive debonding was observed with polyacrylic and phosphoric acid. In the elemental analysis, the intensity of zirconium (depicting the residue of B‑RCS)/zinc (depicting ZOE sealer) was very high on the dentin side treated with saline, in comparison to the dentin treated with polyacrylic and phosphoric acid. Furthermore, the intensity of elements from HVGIC was low on the dentin side of the groups with saline, whereas these elements showed maximum penetration into the dentin when treated with phosphoric acid.

Conditioning of the endodontic access cavity using 37% phosphoric acid immediately postobturation resulted in higher penetration of HVGIC into the dentin, in comparison to the other dentin conditioners.