The effect of different enamel surface treatment methods on the shear bond strength between self-adhesive resin composite and orthodontic brackets

Objective: The current research evaluated the shear bond strength (SBS) of orthodontic brackets with self-adhesive resin composite (FusioTM) with different enamel surface treatment. Materials and methods: Twenty-eight maxillary premolars were divided according to bonding protocol into four groups (n=7). Group 1 brackets were bonded with orthodontic adhesive (Enlight) and primer (orthosoloTM) after etching of enamel surface. The brackets of other three groups were bonded to enamel with FusioTM but with different enamel surface treatment; group 2 brackets bonded directly, Group 3 brackets were bonded after enamel etching, while group 4 brackets were bonded with FusioTM and orthosoloTM after enamel etching. All samples were subjected to SBS followed by determination of adhesive remnant index (ARI) by stereomicroscope. The statistical significance difference was determined by Kruskal-Wallis and Mann-Whitney tests (P ≤ 0.05). Results: Group 1 reported the highest statistically significant difference SBS values (25.66 MPa ± 3.82) followed by group 3 and 4 (11.92 MPa ± 1.88) (9.52 MPa ± 1.66) respectively with no statistically significant difference. However, group 4 recorded least statistically significant difference (5.56 MPa ± 1.33). ARI recorded the most adhesive remained at tooth structure in groups 1,3 and 4 and remained on the brackets in group 4. Conclusion: Self-adhesive resin composite can be used safely for bonding the orthodontic brackets provided that enamel surface etching.