A comparative investigation into relative bond strengths of Damon3, Damon3MX, and APC II brackets using different primer and adhesive combinations

This investigation measured and compared shear bond strength (SBS) and adhesive remnant indices (ARIs) of Damon3 and Damon3MX brackets bonded with their recommended primer/adhesive combination or Transbond XT primer/adhesive, with APC II brackets bonded using Transbond XT. Sixty non-carious human third molars were collected and randomly divided into six equal groups of 10. Amongst these, one group was used to standardize the testing methodology, with the remainder constituting the five experimental groups. Upper right central incisor brackets represented each bracket type. Specifically, Damon3 brackets were bonded using either OrthoSolo primer/Blugloo (recommended) or Transbond XT primer/adhesive; Damon3MX brackets were bonded using OrthoSolo primer/Grengloo (recommended) or Transbond XT primer/adhesive, and APC II brackets were bonded with Transbond XT primer. Brackets were debonded by shear force using an Instron machine and the SBS measured. Scores for ARI were determined for all groups after bracket failure by magnified inspection of the tooth surface. Logrank tests showed a significantly higher SBS with Damon3 brackets bonded with OrthoSolo/Blugloo compared with Transbond XT, but no significant differences between the SBS of Damon3MX brackets bonded with OrthoSolo/Grengloo compared with Transbond XT. There were no significant differences in SBS of all three bracket types when bonded with Transbond XT. Pearson's chi-square test showed no difference in the locus of debond. All three adhesive systems are reliable when bonding Damon3 and Damon3MX brackets. Some caution should be taken when using Damon3 brackets bonded with OrthoSolo/Blugloo due to the higher SBS, although no enamel fractures were noted in this study.