An in vivo study on the merits of two glass ionomers for the cementation of orthodontic bands.

The purpose of this study was to investigate the cariostatic effect of two glass ionomer cements on in vivo demineralization of partly uncovered enamel beneath orthodontic bands. A 4-week clinical trial was conducted on a group of five patients with nine pairs of premolars to be extracted for orthodontic purposes. Specially designed orthodontic bands were cemented with either Ketac-Cem (K-C) or Aqua-Cem (A-C). A local cariogenic milieu was created between the buccal surface of the premolars and the inner surface of the bands to secure plaque accumulation. The mineral content of the teeth was quantified by microradiography. The data were compared with data from a previous study of patients in the same age group with bands that had been cemented with a non-F cement. After comparison with the non-F group, the lesion depth (ld) was reduced by 63% for K-C and by 55% for A-C. This reduction was statistically significant at the 2.5% level (t test). The total mineral loss in teeth cemented with glass ionomer cements (delta Z) was reduced, in comparison with the loss in teeth cemented with non-F cement, by 49% with K-C and by 27% with A-C. The differences were statistically significant only for the K-C group (t test, p less than 0.025). There were no significant differences between the two glass ionomer cements with respect to either lesion depth or total mineral loss values (paired t test; p greater than 0.05). This investigation shows that fluoride released from glass ionomer cements contributes substantially to demineralization "reduction." However, these cements do not provide complete caries protection in sites where access is difficult.