Kohichi Kota

Bactericidal Efficacy of Metronidazole against Bacteria of Human Carious Dentin in vitro

The bactericidal efficacy of metronidazole against bacteria in carious dentin was clarified by measuring (1) the difference between bacterial recovery from suspensions of carious dentin on metronidazole-containing BHI-Blood agar plates (10 micrograms/ml) and control plates and (2) the difference between bacterial recovery from carious lesions of freshly extracted teeth, covered by alpha-tricalcium phosphate (TCP) cement containing metronidazole (5%) for 1-3 days and that covered by TCP only. More than 10(3) bacteria per milligram sample were recovered from carious dentin. More than 99% of the bacteria were, however, not recovered when samples were inoculated on metronidazole-containing BHI-Blood agar plates or when the lesions were covered by TCP cement containing metronidazole, indicating that metronidazole effectively disinfected the carious dentin.

Pulpal response to a new light-activated fluoride releasing liner

The purpose of this study was to investigate the degree of pulp irritation of a newly developed light-activated fluoride-releasing adhesive resin liner using canine teeth compared to the amount caused by a negative control, zinc oxide eugenol cement (ZOE), and a positive control, silicate cement (silicate). In the cases of unexposed pulp, this experimental liner showed none, slight or moderate pulpal changes at 3 d postoperatively. At 30 and 90 d, no pulpal response to the experimental liner was detected in almost all cases. These findings were similar to the ZOE and better than the silicate. There was less evidence of pulpal irritation produced by the experimental liner. This material seems to be safe to the pulp under the conditions of this study.