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Zirconium dioxide silver-doped nanoparticles (ZrO 2 AgDNPs) impacts the adhesive material in terms of its physical characteristics, antimicrobial properties, degree of conversion (DC), and micro-tensile bond strength (μTBS) of orthodontic brackets to the enamel surface. A comprehensive methodological analysis utilizing a range of analytical techniques, including scanning electron microscopy coupled with energy-dispersive x-ray spectroscopy (EDX), Fourier-transform infrared (FTIR) spectroscopy, DC analysis, and μTBS testing. A light-curable orthodontic adhesive, specifically Transbond XT, was combined with ZrO 2 AgDNPs at 2.5% and 5%. As a control, an adhesive with no incorporation of ZrO 2 AgDNPs was also prepared. The tooth samples were divided into three groups based on the weightage of NPs: group 1: 0% ZrO 2 AgDNPs (control), group 2: 2.5 wt% ZrO 2 AgDNPs, and group 3: 5 wt% ZrO 2 AgDNPs. EDX graph demonstrated silver (Ag), Zirconium (Zr), and Oxygen (O 2 ), The antibacterial efficacy of adhesives with different concentrations of NPs (0%, 2.5%, and 5%) was assessed using the pour plate method. The FTIR spectra were analyzed to identify peaks at 1607 cm -1 corresponding to aromatic CC bonds and the peaks at 1638 cm -1 indicating the presence of aliphatic CC bonds. The μTBS was assessed using universal testing machine (UTM) and bond failure of orthodontic brackets was seen using adhesive remanent index (ARI) analysis. Kruskal-Wallis test assessed the disparities in survival rates of Streptococcus mutans. Analysis of variance (ANOVA) and post hoc Tukey multiple comparisons test calculated μTBS values. The lowest μTBS was observed in group 1 adhesive loaded with 0% ZrO 2 AgDNPs (21.25 ± 1.22 MPa). Whereas, the highest μTBS was found in group 3 (26.19 ± 1.07 MPa) adhesive loaded with 5% ZrO 2 AgDNPs. ZrO 2 AgDNPs in orthodontic adhesive improved μTBS and has acceptable antibacterial activity against S mutans. ZrO 2 AgDNPs at 5% by weight can be used in orthodontic adhesive alternative to the conventional method of orthodontic adhesive for bracket bonding. RESEARCH HIGHLIGHTS: The highest μTBS was found in orthodontic adhesive loaded with 5% ZrO 2 AgDNPs. ARI analysis indicates that the majority of the failures fell between 0 and 1 among all investigated groups. The colony-forming unit count of S. mutans was significantly less in orthodontic adhesive loaded with nanoparticles compared with control. The 0% ZrO 2 AgDNPs adhesive showed the highest DC., (© 2024 Wiley Periodicals LLC.)

Aim: To assess bond integrity and failure mode after enamel pretreated with conventional and contemporary conditioning methods were bonded to metallic brackets (MB)., Material and Methods: Forty maxillary central incisors were selected and disinfected. All specimens were mounted up to the cement-o-enamel junction and divided into four experimental groups randomly based on the enamel conditioning technique. Photodynamic therapy (PDT) was used to condition enamel in group 1, Total-etch and rinse (TER) was used to treat samples in group 2, Specimens in group 3 were conditioned with ECL, and samples in group 4 surface pretreated with SEP. Bonding of MB was performed on the surfaces of all the specimens with a Transbond XT. Specimens from all investigated groups were positioned on a universal testing machine maintaining buccal surfaces similar to the direction of the force. After bracket debonding bond failure was assessed using ARI. The bond integrity of all four groups was compared using analysis of variance (ANOVA). Post hoc Tukey test was used for pairwise comparison among different groups., Results: Group 2, TER+MB (15.38±0.14 MPa) displayed the highest bond value whereas the lowest values of SBS were exhibited by group 1, PDT+MB (10.11±0.17 MPa). The inter-group comparison revealed that specimens of group 2 and group 3, ECL+MB (14.61±0.55 MPa) demonstrated comparable bond strength (p>0.05)., Conclusion: Enamel conditioned with TER and ECL demonstrated comparable SBS. However, bond integrity after PDT and SEP (self-etch primer) surface treatment of enamel bonded with MB significantly lowered bond values., (Copyright © 2021. Published by Elsevier B.V.)