Comparison of Proanthocyanidin and EDTA in Enhancing Shear Bond Strength of Giomer and Cention N to Human Dentin: An In vitro Study

Aim: Achieving durable bonding to dentin remains a challenge in restorative dentistry due to its complex structure and composition. Conditioning agents, such as ethylenediaminetetraacetic acid (EDTA) and proanthocyanidins (PACs), are used to modify the smear layer and enhance adhesion. PACs have shown promise in improving bond strength through collagen cross-linking. This in vitro study compared the effects of 17% EDTA and PAC conditioning on the shear bond strength of Giomer and Cention N to human dentin. Materials and Methods: Sixty extracted human premolars and molars were randomly divided into three conditioning groups (n = 20 per group): 17% EDTA (MD-Cleanser, Meta Biomed Co. Ltd., Cheongju, Korea), 6.5% PAC solution, and an intact smear layer (control). Each conditioning group was further subdivided (n = 10 per subgroup) based on the restorative material: Giomer (Beautifil II, Shofu Inc., Kyoto, Japan) and Cention N (Ivoclar Vivadent, Schaan, Liechtenstein). Shear bond strength was measured using an Instron universal testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed using two-way ANOVA and Tukey’s post hoc test. Results: PAC conditioning resulted in the highest mean shear bond strength (5.34 ± 1.93 MPa), significantly higher than the intact smear layer (3.77 ± 1.74 MPa; mean difference = 1.57 MPa, P = 0.008). No statistically significant difference was found between PAC and 17% EDTA (4.55 ± 1.64 MPa). Giomer (5.33 ± 1.86 MPa) exhibited significantly greater shear bond strength than Cention N (3.78 ± 1.52 MPa; mean difference = 1.55 MPa, P < 0.001) across all conditioning methods. Conclusion: PAC conditioning significantly improved the shear bond strength of Giomer and Cention N to dentin compared to the intact smear layer. Giomer demonstrated superior bond strength compared to Cention N regardless of the conditioning agent used. These findings suggest that PAC may be a promising dentin conditioning agent for enhancing the durability of bonded restorations. Further clinical studies are warranted to validate these in vitro findings.