The effect of a resin-modified glass ionomer restorative material on artificially demineralised dentine caries in vitro

OBJECTIVES: Recurrent caries is one of the most common reasons for the replacement of restorations. One method of reducing the frequency of this problem may be by using fluoride-releasing restorative materials. The aim of this in vitro study was to evaluate the progression of artificial lesions around resin-modified glass ionomer (Vitremer) restorations placed in root surfaces. Class V cavities were prepared on the mesial and distal surfaces of 28 human premolar teeth. Artificial carious wall lesions were created in all cavities. The root of each tooth was then hemisected through the middle of the two cavities, before being restored with either the glass ionomer or amalgam, while the opposing cavities on the same root portion were varnished as negative controls. Forty-eight specimens were pH-cycled in remineralising and demineralising solutions for 20 h and 4 h, respectively, each day for 4 weeks, whilst in a smaller control group of eight specimens, the demineralising solution was replaced with deionised water. Mineral changes in the carious lesions were evaluated using contact microradiography. RESULTS: Results showed that varying degrees of subsurface demineralisation and remineralisation were evident, with a laminated appearance in lesions adjacent to the glass ionomer. There was higher remineralisation in the glass ionomer-filled cavities compared with the amalgam-filled cavities. In the water-cycled group, glass ionomer showed an increase in mineral content (p < 0.05), while no changes were observed in the amalgam-filled cavities. CONCLUSIONS: This model has shown that glass ionomer has a greater potential than amalgam for remineralisation of artificially created wall lesions within an acidic environment.