Comparison of bond strength and adhesive remnant index of 3-dimensional-printed orthodontic brackets fabricated with different resins and surface treatments

Introduction This study evaluated the shear bond strength (SBS), maximum debonding force (MDF), and adhesive remnant index (ARI) of 3-dimensional-printed brackets made from 3 resins after different base treatments.Methods Premolars (n = 240) were assigned to 12 groups (n = 20). Brackets were printed from Saremco Print Crowntec, VarseoSmile Crown plus, or P-Crown V3 with retention grooves (G1), aluminum oxide air abrasion (G2), erbium, chromium:yttrium-scandium-gallium-garnet laser treatment (G3), or as-printed bases (G4). After thermocycling, SBS, MDF, ARI, and structural fracture incidence were evaluated. SBS and MDF were analyzed using 2-way analysis of variance followed by Tukey honestly significant difference tests, whereas ARI and fracture incidence were analyzed using Fisher-Freeman-Halton exact tests. The SBS sensitivity analysis excluded specimens with enamel or bracket fractures.Results Resin type and surface treatment affected SBS (both P Conclusions All groups, including the untreated G4 group, exceeded the 6-8 MPa laboratory benchmark. G2 and G3 increased SBS, whereas the G1 design increased MDF. These findings should be considered alongside failure mode and the potential for enamel damage.