An in vitro dynamic microcosm biofilm model for caries lesion development and antimicrobial dose-response studies

Abstract

Some dynamic biofilm models for dental caries development are limited as they require multiple experiments and do not allow independent biofilm growth units, making them expensive and time-consuming. This study aimed to develop and test an in vitro dynamic microcosm biofilm model for caries lesion development and for dose-response to chlorhexidine. Microcosm biofilms were grown under two different protocols from saliva on bovine enamel discs for up to 21 days. The study outcomes were as follows: the percentage of enamel surface hardness change, integrated hardness loss, and the CFU counts from the biofilms formed. The measured outcomes, mineral loss and CFU counts showed dose-response effects as a result of the treatment with chlorhexidine. Overall, the findings suggest that biofilm growth for seven days with 0.06 ml min⁻¹ salivary flow under exposure to 5% sucrose (3 × daily, 0.25 ml min⁻¹, 6 min) was suitable as a pre-clinical model for enamel demineralization and antimicrobial studies.

Keywords:

• Biofilm model
• enamel demineralization
• artificial dental caries
• chlorhexidine

Acknowledgements

The authors thank the laboratory technicians Carmem Lúcia Machado Lopes and Lizângela Ferreira (Laboratory of Oral Microbiology-School of Dentistry, UFPel, Pelotas, RS, Brazil). This study is based on the first author’s Masters Dissertation (Graduate Program in Dentistry, Restorative Dentistry Area, School of Dentistry, UFPel).

Disclosure statement

No potential conflict of interest was reported by the authors.