2014 Volume 57 Issue 3 Pages 229-238
Purpose: Restorations with gold-silver-palladium alloy discolor in the oral cavity of patients and produce a large amount of volatile sulfur compounds (VSCs). Zeolite A and Hydrotalcite have been developed as new materials to adsorb VSCs (VSC adsorbents). In the present study, the effects of VSC-producing bacteria on gold-silver-palladium alloy and the inhibitory effects of VSC adsorbents on the discoloration were investigated.
Methods: Gold-silver-palladium alloy was added to BHI media (supplemented with L-cysteine) containing three periodontal pathogenic bacterial species (Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum) and one cariogenic bacterial species (Streptococcus mutans), followed by anaerobic culture at 37℃ for four weeks. This culture was conducted with or without a VSC adsorbent. After the culture, the glossiness and color of the gold-silver-palladium alloy were examined.
Results: After the culture, the glossiness of the gold-silver-palladium alloy was reduced in the presence of all four bacterial species. The addition of a VSC adsorbent significantly suppressed the reduction. Discoloration was also observed. The VSC adsorbent tended to reduce color difference values. Of note, the color difference values were significantly reduced by adding Zeolite A after culture with Porphyromonas gingivalis.
Conclusion: The tested bacteria reduced the glossiness and caused the discoloration of the gold-silver-palladium alloy. The tested VSC adsorbents adsorbed the VSCs of oral bacteria, suppressing the discoloration of gold-silver-palladium alloy.
