Fluoride-releasing materials have been reported to be bactericidal in
vitro. This may be of benefit to modem dentistry, which is directed to
the preservation of tooth tissue during restorative treatment. Little
is known about in vivo effects. The aim is to investigate the influen
ce of a resin-modified glass ionomer cement (RM-CIC) on carious dentin
e that remains under restorations, compared to amalgam. Using a split
mouth design, 40 molar pairs in 40 patients (mean age 14.9 years) were
selected, based on clinically and radiographically diagnosed occlusal
dentine caries. Under aseptic conditions, the enamel was removed and
the carious dentine was sampled just beneath the dentino-enamel juncti
on using a round bur. Without further removal of carious dentine, the
molars of a pair were alternately restored with RM-GIC or amalgam. The
colour and the consistency of the carious dentine were assessed. The
samples were processed for microbiological determination of total viab
le counts (TVC), mutans streptococci (MS), and lactobacilli (LB). Afte
r 6 months the molars were reopened, similarly sampled and evaluated,
and then permanently restored after complete caries removal. For both
materials a substantial decrease in the numbers of TVC, MS and LB was
found after the 6-month period. Also a positive effect was observed on
the colour and the consistency of the remaining carious dentine, whic
h was comparable for the two materials. RM-GIC showed a significantly
larger decrease in counts of MS and LB than amalgam, but not for TVC.
Since in only few cavities the number of bacteria decreased under the
level of detection, it is still considered essential to remove all car
ious dentine during restorative treatment.