Different Wire Surface Treatments on Adhesion Efficacy of Orthodontic Fixed Retainer: An In Vitro Study

Abstract

Aim: This study assesses the impact of surface treatment with sandblasting and Z-primer on the adhesion efficacy of fixed lingual retainers. Materials and methods: Dead soft stainless steel wire 0.016 × 0.022-inch (n = 120) was treated by different techniques and classified into four groups equally (n = 30) according to surface treatment. Group I wire without treatment, group II wire treated with sandblasting, group III wire treated with Z-primer alone, and group IV wire treated with sandblasting with Z-primer. The stainless steel wire (n = 40) was bonded to 80 extracted premolars in pairs mounted in acrylic. Other stainless steel wires (n = 80) are embedded into acrylic blocks. All groups were divided into two subgroups according to thermocycling teeth samples were assessed by shear bond strength (SBS) A stereomicroscope was used to calculate the adhesive remnant index (ARI), while the acrylic block was by pull-out test. Finally, data were analyzed by IBM-SPSS (V 27, 2020). Mann–Whitney U-test; Kruskal–Wallis H-test and, two-way ANOVA were utilized to assess for SBS and pull-out. Results: Kruskal–Wallis H-test showed a non-significant difference in ARI between all groups, while in two-way mixed ANOVA demonstrated a significant difference in SBS between group III (sandblasting/Z-primer) vs group I and group IV Z-primer (p = 0.028) and control (p = 0.016), and a significant difference between group II sandblasting vs both group I and group IV Z-primer (p = 0.024) and control (p = 0.014). The two-way mixed ANOVA tests showed a significant difference in pull-out between sandblasting/Z-primer vs Z-primer (p = 0.012). Conclusion: Using of mixed surface treatment for fixed retainer as sandblasting with Z-primer is considered as the best method to increase adhesion efficacy between wire and composite and improve the quality of orthodontics fixation when compared with single treatment (sandblasting alone or Z prime). On the other hand, the sue of sandblasting alone for fixed retainer surface treatment is better than Z-primer alone but both treatments are better than fixed retainer without treatment. Clinical application: Developed and examined new and traditional techniques used to treat the surface of wire used as a retainer after orthodontics treatment to improve patients’ treatment and life quality and decrease the chance of relapse.