A reproducible oral microcosm biofilm model for testing dental materials

Abstract

Aims 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 disks 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 were analyzed 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 Veilonella. Biofilms from the same donor, grown at different times, clustered together. Conclusions 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.

The Limitations of In Vitro Experimentation in Understanding Biofilms and Chronic Infection

“…This system has been heavily used to identify potential anti-biofilm agents, by measuring the reduction in surface attached biomass on the sides of wells after treatment with potential therapeutic agents [51][52][53][54]. In addition to this, The Center for Disease Control (CDC) approved biofilm reactor [55][56][57], and drip flow reactors, have proved excellent for assessing biofilm formation on biological and non-biological materials [58][59][60]. These flow systems and microtitre assays are the workhorses of in vitro biofilm research, and have generated a phenomenal amount of data that has greatly expanded our knowledge about how bacteria attach and differentiate into mature biofilms in vitro.…”

Sucrose Induced Dentin Demineralization in a Microcosm Biofilm Model

“…This result was expected because the permanent sucrose supply enables the natural selection of a less diverse, more acidic microbiota and therefore, the pH remains low (Aas et al, 2005;Rudney et al, 2012).…”

Application of a Novel Tongue Resin Replication System for in vitro Biofilm Studies

“…In view of the multiplicity/heterogeneity of oral biofilm populations, simultaneous multispecies evaluations of the oral microcosm are of a high level of complexity [22,23]. However, the utilisation of an in vitro model system with a highly complex bacterial diversity, and which also supports the growth of uncultivated oral species, is highly desirable, since it may be manipulated and explored within a controlled environment [23].…”

“…However, the utilisation of an in vitro model system with a highly complex bacterial diversity, and which also supports the growth of uncultivated oral species, is highly desirable, since it may be manipulated and explored within a controlled environment [23].…”