The Performance of Universal Adhesives on Orthodontic Bracket Bonding

Abstract Objective This article aimed to assess the effects of double application of universal adhesives on the shear bond strength of orthodontic brackets. Materials and Method Seventy-five extracted human premolars were used. The teeth were randomly assigned into five groups based on the adhesive procedure (n = 15). The universal adhesives Scotchbond Universal (3M Oral Care) and Prime&Bond Universal (Dentsply) were used (following manufacturer’s instructions and double application). Transbond XT Primer (3M Unitek) was employed as control. Following adhesive application, the brackets were bonded on the tooth surfaces. After storage in distilled water for 24 hours at 37°C, the specimens were subjugated to the shear bond strength test under a universal testing machine (Autograph AGS-X; Shimadzu). Data were analyzed with one-way analysis of variance and least significant difference tests (p = 0.05). The adhesive remnant index (ARI) was determined using a stereomicroscope (S4E; Leica Microsystems). Data of ARI scores were submitted to Pearson’s chi-square test. Results The highest shear bond strengths were acquired with Scotchbond Universal (p < 0.05). The double application of Scotchbond Universal did not impact the shear bond strength. The lowest shear bond strength was found in Prime&Bond Universal (p < 0.05). The double application of Prime&Bond Universal increased the shear bond strength (p < 0.05). There were no significant differences in ARI scores among the groups (p > 0.05). Conclusion The universal adhesives may be an alternative for the bonding of orthodontic brackets. The double application of universal adhesives might improve the shear bond strength of orthodontic brackets depending on the material.