Effect of açai berry extract application on the bond strength to the bleached enamel using an experimental etch-and-rinse adhesive

Abstract

Background To evaluate the bleached enamel shear bond strength (SBS) after antioxidants application using an experimental adhesive. Material and Methods Sixty sound human molars had their roots removed then cut into buccal and lingual halves and mounted in acrylic blocks. Enamel bleaching was done using an in-office chemical bleaching agent. Specimens were arbitrarily allocated into 12 groups (n=10) regarding the three experimental levels of the study: two antioxidant agents [10% açai berry extract, 10% sodium ascorbate prepared gels (applied for 15-min) and the control group (no antioxidant application)], two adhesive materials [commercial etch-and-rinse (ER) adhesive and an experimental ER adhesive] and two post-bleaching SBS testing times [24-h and 2-w]. Specimens were restored with a nano-hybrid resin composite restoration then stored in distilled water at 37◦C till SBS testing. Results Three-way ANOVA showed that the antioxidant agents, adhesive materials and the post-bleaching SBS testing times had a statistically significant effect on the bleached enamel SBS. Açai berry extract groups recorded the highest mean values, while the control groups demonstrated the least values with a statistically significant difference between the antioxidant agents’ groups. Commercial ER adhesive recorded statistically significant higher SBS values than the experimental adhesive and the 2-w post-bleaching SBS testing time demonstrated statistically significant higher SBS values than the 24-h groups. Conclusions Açai berry extract is a powerful antioxidant agent, that has the potential to instantly restore the bleached enamel depleted SBS. The commercial adhesive has successfully restored the depleted SBS of the bleached enamel than the tested experimental adhesive. Key words: Antioxidant application, açai berry extract, etch-and-rinse adhesives, experimental adhesive, shear bond strength.

One-Step Surface-Treatment Reagent (35% 3-O-Ethyl-l-ascorbic Acid Plus 50% Citric Acid Solution) Restores the Shear Bond Strength of Metal Brackets Bonded to Bleached Human Enamel: An In Vitro Study

“…There are several in vitro studies that used different natural antioxidants, including pine bark extract, green tea extract, grape seed extract, and lycopene, as a surface treatment following tooth bleaching and before the bonding process [21][22][23]. These studies observed that natural antioxidants enhanced the bond strength to bleached enamel; however, these antioxidants required an application time longer than 10 min [23].…”

“…Despite its potential benefits, using sodium ascorbate for bonding requires an extra etching procedure with phosphoric acid [15,[17][18][19][20], which conflicts with the preference for rapid treatment among patients at present. Moreover, sodium ascorbate has a short shelf life and is highly unstable, and rapidly oxidizes after being exposed to the air [21,22]. Using a combination of antioxidant and acid etching solutions is a promising approach to reduce the total working time and improve the clinical benefits.…”

“…Using a combination of antioxidant and acid etching solutions is a promising approach to reduce the total working time and improve the clinical benefits. However, sodium ascorbate's instability in the presence of water and oxygen, as well as its neutral pH, make it unsuitable to use in conjunction with acidic solutions [21,23]. Therefore, it is necessary to explore alternative derivatives of ascorbic acid and etchants that are better suited for this purpose.…”