Development of dentin caries lesions in an in vitro simplified biofilm model: a pilot study

Abstract Introduction Oral laboratory biofilm models have been developed to reproduce the oral environment and the process of caries lesion formation in vitro. Objective To establish and standardize an in vitro biofilm model for the development of caries lesions in dentin. Material and method Twelve standardized bovine dentin discs were assigned into three experimental times: 4, 7, and 10 days. Samples of each experimental period were inoculated with Streptococcus mutans UA 159 in a BHI culture medium with 1% sucrose, and cultured under anaerobic conditions. The integrated hardness loss (ΔS) of dentin discs and the hardness of the substrate at different depths were considered as response variables. The ΔS data were analysed by ANOVA followed by Tukey's test, both with significance level of 5%, and the data of hardness at different depths were analysed descriptively. Result There was a higher hardness loss after 10 days of microbial growth when compared to 4 days (p = 0.034), however, there was no difference between 7 and 10 days (p = 0.853). The 4-day group showed loss of hardness of the surface layers (10-40μm) and the 10-day group showed demineralization in the deeper area around 150µm. Conclusion The proposed model was able to develop artificial caries lesions in dentin. In 7 days, the dentin sub superficial lesions were suitable to des-remineralisation studies.