The Effect of Bonding Techniques on Bond Strength of Core Buildups in Simulated Endodontic Accesses in Zirconia Crowns

Abstract

Objective(s)

Providers frequently opt to perform root canal therapy through pre-existing full-coverage restorations, subsequently repairing the access cavity with a composite restoration. The capacity to effectively bond zirconia remains a subject of ongoing debate. Particularly in the anterior region, zirconia crown restorations underscore the importance of evaluating the bond strength between composite restorations and zirconia crowns. The objective of this study is to assess whether the choice of bonding technique enhances the shear bond strength of repaired endodontic accesses in zirconia crowns.

METHODS

Researchers milled forty zirconia discs to include a simulated endodontic access. The discs were divided into four groups consisting of dual cure and light cure resins bonded with two bonding systems. Researchers performed pushout testing using an Instron machine and evaluated the results using Fisher’s Exact test.

RESULTS

The study found a statistically significant difference in shear bond strengths between dual-cure and light-cure adhesives with MDP, with a P-value of 0.023. No other groups showed statistical significance, although the dual-cure adhesive groups exhibited 2 to 4 times more bonded specimens than the light-cure adhesive samples.

Conclusion

The findings of this study underscore the ongoing challenges in achieving a durable bond between composite resins and zirconia materials. Despite the use of different resin-based materials and bonding systems, the bond strengths remain insufficient for achieving optimal clinical performance, especially in the anterior region where esthetics and longevity are paramount.