Demineralization Around Orthodontic Brackets Bonded with Resin-modified Glass Ionomer Cement and Fluoride-releasing Resin Composite

Purpose: Enamel demineralization adjacent to orthodontic brackets is one of the risks associated with orthodontic treatment. Glass ionomer cements have been shown to decrease enamel demineralization adjacent to brackets and bands but do not exhibit bond strengths comparable to resin composites. The purpose of this in vitro study was to compare a fluoride-releasing resin composite versus a resin-modified glass ionomer cement for inhibition of enamel demineralization surrounding orthodontic brackets.

Methods: Forty-five teeth were randomly assigned to 3 groups of 15 teeth. Fifteen were bonded with Concise (3M), a non-fluoride-releasing resin composite (control); 15 teeth were bonded with Light Bond (Reliance), a fluoride-releasing resin composite; and 15 teeth were bonded with Fuji Ortho LC (GC Corporation), a resin-modified glass ionomer cement. The teeth were placed in an artificial caries solution to create lesions. Following sectioning of the teeth in a buccolingual direction, polarized light microscopy was utilized to evaluate enamel demineralization adjacent to the orthodontic bracket. The area of the lesion was measured 100 microns from the orthodontic bracket and bonding agent.

Results: MANOVA (P < .0001) and Duncan's test (P < .05) indicated the resin-modified glass ionomer cement (Fuji Ortho LC) and the fluoride-releasing resin composite (Light Bond) had significantly less adjacent enamel demineralization than the non-fluoride-releasing resin composite control. However, there was no significant difference between the resin-modified glass ionomer cement and the fluoride-releasing resin composite.

Conclusions: Based on the results of this in vitro study, it can be concluded that Fuji Ortho LC and Light Bond exhibit significant inhibition of adjacent demineralization compared to the non-fluoride-releasing control.