In Vitro Evaluation of Shear Bond Strength of Orthodontic Metal Brackets to Aged Composite Using a Self-Adhesive Composite: Effect of Surface Conditioning and Different Bonding Agents Publisher Pubmed



Valizadeh S^{1, 2} ; Alimohammadi G³ ; Nik TH⁴ ; Etemadi A^{1, 5} ; Tanbakuchi B^{1, 4}
Source: International Orthodontics Published:2020

Abstract

Objectives: Bracket bonding to composite surfaces is increasing. This study sought to assess the effect of different adhesives (acid etchant + Transbond XT™, acid etchant + Vertise Flow™, Vertise Flow™) with different surface treatments (no preparation, bur, sandblasting, Er:YAG laser) on shear bond strength (SBS) of metal brackets to aged composite. Materials and methods: In this in vitro, experimental study, Filtek™ Z250 composite discs were fabricated (10 × 4 mm). After thermocycling (10,000 cycles between 5–55 °C), the samples were randomly divided into three groups (n = 48) based on the type of adhesive namely acid etchant + Transbond XT™, Vertise Flow™, and acid etchant + Vertise Flow™. Samples in each group were randomly divided into four subgroups (n = 12) based on the surface treatment including no-treatment, diamond bur, sandblasting and Er:YAG laser. Samples in each group were randomly divided into three subgroups (n = 12) based on the type of adhesive namely acid etchant + Transbond XT™, Vertise Flow™, and acid etchant + Vertise Flow™. After bracket bonding to composite discs, the samples underwent thermocycling (5000 cycles between 5–55 °C), and their SBS was measured in a universal testing machine. The samples were then inspected under a stereomicroscope at x10 magnification to determine their mode of failure and adhesive remnant index (ARI). Results: No significant difference was noted in SBS between adhesives in no-preparation and laser groups (P > 0.05). In all adhesive groups, sandblast had highest SBS, but it was not significantly different in Vertise Flow™ groups, with and without etching. The SBS provided by acid etchant + Transbond XT™ was significantly higher than that of the other two adhesives (P < 0.05). The SBS of sandblasted samples was significantly higher compared with other surface treatments in all adhesive subgroups (P < 0.05). Conclusion: Bracket bonding to aged composite using Vertise Flow™ with or without surface treatment can serve as an alternative to the conventional orthodontic adhesives. © 2020 CEO