An in vitro caries inhibition of photopolymerized glass ionomer liners

Caries inhibition of traditional chemical cure glass ionomers has been established. The newer photopolymerized glass ionomers demonstrate a different composition that may impair the ability of providing prevention to secondary caries at restoration margins. The purpose of this study was to evaluate the caries inhibition of photopolymerized glass ionomers (Vitrebond®-3M Dental Products, Photac® Bond-ESPE/Premier Dental Products) compared to a photopolymerized composite resin (Pertac® Universal Bond-ESPE/Premier) control. Two standardized Class V preparations were placed in thirty permanent molars, the gingival margin placed below the cementoenamel junction. Equal numbers of preparations were restored with Vitrebond®, Photac® Bond and Pertac® Universal Bond, according to manufacturer's instructions. The teeth were coated with an acid resistant varnish to within 2 mm of the restoration margins. All teeth were subjected to an artificial caries challenge (pH 4.2) for five days, then axial sections of 100 μm were cut longitudinally through the restored margins and photographed under polarized light microscopy. The polarized micrographs were projected onto a digitizing pad, where demineralized areas adjacent to the restoration margins were quantitated. Results demonstrated the mean (± S.D.) area (μm²) demineralization 100 μm from the restoration gingival margin to be: Photac® Bond 66.1 ± 27.8; Vitrebond® 47.2 ± 37.2; Pertac® Universal Bond 120.9 ± 66.0. Duncan's multiple range test indicated there was no statistically significant difference in demineralization inhibition between the two photopolymerized glass ionomers Photac® Bond and Vitrebond® (p < 0.05), but both photopolymerized glass ionomers demonstrated significantly less demineralization than the Pertac® Universal Bond composite resin control (p < 0.05).