Evaluation of the Effect of Chitosan-Based Irrigation Solutions on the Bond Strength of Mineral Trioxide Aggregate to Bulk-Fill Composite

Abstract

(1) Background: Bond strength between repair and restorative materials is crucial for endodontic success. This study assessed the effects of the following final irrigation solutions on the bond strength of mineral trioxide aggregate (MTA) to a bulk-fill composite: (1) 17% Ethylenediamine tetraacetic acid (EDTA); (2) 2% Chlorhexidine (CHX); (3) 0.2% chitosan; (4) 0.2% chitosan with 2% CHX; 5) 0.2% chitosan with AgNPs. (2) Methods: Sixty MTA samples were divided into six groups (n = 10) based on the final irrigation solution: 1. EDTA, 2. CHX, 3. Chitosan, 4. Chitosan-CHX, 5. Chitosan-AgNP, and 6. distilled water (control). After a 5-min solution exposure, each sample was restored with the bulk-fill composite, and the shear bond strength (SBS) was measured. Structural changes in MTA were analyzed using SEM and EDS, and failure modes were classified as adhesive, cohesive, or mixed. Data were analyzed by one-way ANOVA with Tamhane's T2 and Tukey's tests (α = 0.05). (3) Results: EDTA exhibited the lowest SBS (p < 0.001), while Chitosan-CHX showed the highest. SEM showed a spongy, void-rich surface in EDTA-treated MTA, with significant Ca depletion per EDS. Chitosan-CHX showed no structural change. Cohesive fractures within MTA were predominant. (4) Conclusions: EDTA significantly reduces SBS, while chitosan with CHX enhances bond strength.

Keywords: bulk-fill composite; chitosan; cholorhexidine; ethylenediaminetetraacetic acid; mineral trioxide aggregate; nanoparticles; shear bond strength.

Figure 1

An illustration showing preparation of the specimens for shear bond strength test.

Figure 2

(a) MTA samples. (b) MTA samples embedded in cold acrylic and bulk fill composite in cylinder tubes. (c) Ready samples for bonding test. (d) Application of shear bond test on a sample.

Figure 3

Bar chart showing shear bond strength values (MPa) (Mean ± SD) for each group, with statistical significance annotations (“a”, “b”, “c”) and corresponding p-values displayed.

Figure 4

A representative image of the failure types: adhesive failure (a), cohesive failure in MTA (b), mixed failure (c).

Figure 5

Scanning electron microscopy images of MTA specimens after exposure 17% EDTA, 2% CHX, 0.2% chitosan solution, 0.2% chitosan solution containing 2% CHX, 0.2% chitosan solution containing AgNPs, and distilled water (10,000× magnification and 10 kV).

Figure 6

Representative energy-dispersive spectroscopy image of MTA treated with 17% EDTA, 2% CHX, 0.2% chitosan solution, 0.2% chitosan solution containing 2% CHX, 0.2% chitosan solution containing AgNPs and distilled water.