Evaluation of bonded orthodontics brackets using different adhesive systems after a cariogenic challenge

The aims of this study were to evaluate the prevention of enamel demineralization and the shear bond strength (SBS) of orthodontic brackets bonded with fluoride and no fluoride conventional and self-etching adhesives and to analyze the characteristics of enamel near the bond area using a polarized light microscope (PLM) following demineralization and remineralization cycling (Des Re).

Fifty bovine incisors were selected and divided into five groups according to the adhesive system used during the bonding process: G1, Transbond XT Adhesive; G2, Single Bond 2 Adhesive; G3, Optibond Solo Plus; G4, Clearfil SE Bond; and G5, Clearfil Protect Bond. Transbond XT was used to fix the brackets to the teeth in all groups. After bonding, the groups were separated into cycling and control subgroups. The specimens were submitted to SBS testing and evaluated under a PLM. The results were submitted to ANOVA and Tukey's post hoc tests (p<.05).

There were no significant differences for SBS after Des-Re cycling. The Clearfil Protect Bond showed the SBS to be statistically lower than the other adhesives used for the control groups. After a cariogenic challenge, the Single Bond adhesive showed an SBS significantly lower than Transbond XT. The Des-Re cycling increased the enamel demineralization induced after the cariogenic challenge.

The cariogenic challenge did not reduce the SBS. Optibond Solo Plus and Transbond XT adhesives presented the highest SBS while Clearfil Protect Bond had the lowest. The PLM showed that the cariogenic challenge increased the enamel demineralization for all adhesives evaluated, independent of the presence of fluoride.

An alternative material with the ability to prevent enamel demineralization should be used in orthodontic patients due to the higher accumulation of plaque around orthodontic brackets.