Shear bond strength of a RMGIC for orthodontic bracket bonding to enamel

OBJECTIVE: To evaluate the shear bond strength (SBS) of a restorative resin-modified glass ionomer cement (RMGIC) for orthodontic bracket bonding. MATERIALS AND METHODS: 121 human teeth were randomly divided into 11 groups (n = 11) according to enamel surface treatment (H₃PO₄ ± Transbond Plus (TSEP) or Scotchbond Universal (SU)) and adhesive used (Riva LC HV (RIVA), Fuji Ortho LC (FUJI), Transbond XT (TXT)). Metal buttons were bonded and SBS tested at 1 week; failure modes were assessed. One-way ANOVA with Tukey’s post hoc test compared SBS; Fisher’s exact test analyzed failure modes (p < 0.05). RESULTS: TSEP + FUJI and H₃PO₄ + SU + TXT had the highest SBS, while H₃PO₄ + TSEP + RIVA had the lowest. Cohesive and mixed failures occurred with SU + TXT groups; other groups were predominantly adhesive failures. DISCUSSION/CONCLUSIONS: All three materials can bond orthodontic attachments to enamel; use of a universal adhesive may optimize adhesion values. Clinical studies are needed to confirm in vitro findings.