In situ anticariogenic potential of conventional and resin-modified glass ionomer cement

Objectives: Conventional and resin-modified glass ionomer cements (GIC) presented different effects on plaque composition and ion release in a previous in vitro study. Thus, the aim of this study was to evaluate the effect of conventional and resin-modified GIC on dental plaque composition, cariogenic microbiota and secondary caries formation under in situ conditions of high cariogenic challenge. Methods: Nine volunteers took part in this crossover study performed in 3 phases of 21 days each. Human enamel blocks were restored with composite (control group – Z 100®), conventional GIC (Ketac®) or resin-modified GIC (Vitremer®). Palatal appliances, containing 4 blocks restored with the same material, were constructed for each of the volunteers. During the experimental period, all subjects used non-fluoridated dentifrice, refrained from brushing the blocks and dripped extra-orally a 20% sucrose solution onto each enamel block, 8 times a day. After the experimental period, cross-sectional microhardness was determined in enamel around the restorations at 20, 40, 60 and 80 µm from the outer enamel surface and dental plaque was collected and analyzed for fluoride, insoluble polysaccharide (IP) and the proportion of mutans streptococci. Results: The results (means ± sd) according to the treatments composite, conventional and resin-modified GIC were, respectively: 1) CSMH at 20 µm: 185.2 ± 52.3a, 332.4 ± 35.1b, 296.5 ± 30.9a; 2) F (µg/g): 4.17 ± 3.4a, 8.28 ± 7.94a, 15.83 ± 23.62a; 3) IP (mg/g): 37.32 ± 36.48a, 28.92 ± 21.39a, 26.58 ± 23.16a; 4) % mutans streptococci: 1.34 ± 2.33a, 1.14 ± 1.39a, 0.36 ± 0.36a. Treatments whose means are followed by distinct letters differ statistically (p<0.05). Conclusions: Even though no significant change was observed in dental plaque composition or proportion of mutans streptococci, both GICs, conventional and resin-modified, were able to reduce enamel demineralization under a severe cariogenic challenge. Supported by FAPESP - 00/01474-6