Methods:Three column specimens were prepared from each of the following materials: glass ionomer, composite resin, dental amalgam. And Hydroxyapatite was utilized as a control. Unstimulated whole saliva was collected from 4 healthy adults. The mixed salivary bacteria were inoculated to form 7 d biofilm on saliva-coated column specimens which was placed in 24-well plate in batch with 5% CO2 at 37BC. Biomass, aciogenicity and aciduricity of biofilm were detected. And 16S rDNAs of aciduric biofilm cells on different restorative materials were amplified and sequenced.
Results: The results showed that the higher adhesion was found on composite resin and glass ionomer than dental amalgam. The biofilm formed on glass-ionomer has the highest acid production capacity, but showed less aciduricity. Contrarily, the biofilm formed on dental amalgam presented high aciduricity but low acidogenity. The biofilm of composite resin was in the mediate position. Most aciduric bacteria adhered on dental amalgam were Lactobacilli and those on glass ionomer were Streptococci.
Conclusion:In summary, dental restorative materials differ in terms of bacterial colonization. The biofilm formed by different species or different proportion of oral bacteria will demonstrate various acidogenicity and aciduricity.