A reproducible oral microcosm biofilm model for testing dental materials



Joel D. Rudney, Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, 17-252 Moos Tower, 515 Delaware St. SE, Minneapolis, MN 55455, USA. E-mail: jrudney@umn.edu



Most studies of biofilm effects on dental materials use single-species biofilms, or consortia. Microcosm biofilms grown directly from saliva or plaque are much more diverse, but difficult to characterize. We used the Human Oral Microbial Identification Microarray (HOMIM) to validate a reproducible oral microcosm model.

Methods and Results

Saliva and dental plaque were collected from adults and children. Hydroxyapatite and dental composite discs were inoculated with either saliva or plaque, and microcosm biofilms were grown in a CDC biofilm reactor. In later experiments, the reactor was pulsed with sucrose. DNA from inoculums and microcosms was analysed by HOMIM for 272 species. Microcosms included about 60% of species from the original inoculum. Biofilms grown on hydroxyapatite and composites were extremely similar. Sucrose pulsing decreased diversity and pH, but increased the abundance of Streptococcus and Veillonella. Biofilms from the same donor, grown at different times, clustered together.


This model produced reproducible microcosm biofilms that were representative of the oral microbiota. Sucrose induced changes associated with dental caries.

Significance and Impact of the Study

This is the first use of HOMIM to validate an oral microcosm model that can be used to study the effects of complex biofilms on dental materials.