Effect of the Incorporation of Chitosan and TiO <sub>2</sub> Nanoparticles on the Shear Bond Strength of an Orthodontic Adhesive: An In Vitro Study
Fahimeh Farzanegan, Hooman Shafaee, Majid Darroudi, Abdolrasoul Rangrazi
Abstract
Aim: This in vitro study was aimed to evaluate the effect of adding different concentrations of chitosan nanoparticles (NPs) and TiO 2 NPs on the shear bond strength (SBS) of an orthodontic adhesive. Materials and Methods: In this in vitro study, 72 extracted human premolars were embedded in an acrylic resin and randomly allocated into four groups of 18 specimens. In group 1 (control), brackets were bonded to the tooth with the Transbond XT orthodontic adhesive. In groups 2, 3, and 4, 0.5% chitosan NPs and 0.5% TiO 2 NPs, 1% chitosan NPs and 1% TiO 2 NPs, and 1.5% chitosan NPs and 1.5% TiO 2 NPs were added to Transbond XT, respectively. Then, the brackets were bonded by the modified adhesive. The SBS and adhesive remnant index (ARI) of each group were assessed with a universal testing machine. The SBS test results were analyzed using one-way analysis of variance followed by the posthoc Tukey’s honestly significant difference (HSD) test. The Kruskal–Wallis test was also applied to evaluate the ARI scores. Results: The results showed no statistically significant difference between groups 1, 2, and 3, but SBS decreased significantly in group 4. With increasing the concentration of NPs up to 1% chitosan NPs and 1% TiO 2 NPs, SBS did not change significantly. However, in 1.5% chitosan NPs and 1.5% TiO 2 NPs, SBS decreased compared to the other three groups. No significant differences were found between the groups in terms of ARI scores. Conclusion: It is concluded that the orthodontic composite containing 1% chitosan NPs and 1% TiO 2 NPs has adequate SBS for use in the clinical setting.