An in vitro microbial model associated with sucrose to produce dentin caries lesions

Abstract

The complexity of the oral environment and ethical issues have prompted the development of an in vitro bacterial model to evaluate the effect of frequency of sucrose exposure on dentin caries formation, biofilm composition, and pH changes. In the experiment, dentin specimens (n=45) were randomly divided into four groups: control (C), negative control (0S), 3S (three sucrose baths), and 6S (six sucrose baths). The specimens then were inoculated with Streptococcus mutans and treated according to the protocol described below. Dentin demineralization and lesion depth were assessed by transverse microradiography. Extracellular polysaccharides that formed in the biofilm were analyzed and counts of microorganisms in the carious dentin were measured. After a 7-day period of growth, the biofilm pH was assessed before and after sucrose baths (n=5). The addition of sucrose led to dentin caries development regardless of the number of sucrose baths performed. The number of colony forming units (cfu) from the carious dentin did not differ among the treatment groups, though the extracellular polysaccharides from both 3S and 6S differed from 0S. The pH decreased immediately after the sucrose bath but increased again after 5 min. We demonstrate here that the in vitro microbial model for the study of dentin caries formation is reproducible and able to produce dentin caries, irrespective of the frequency of sucrose exposure.

Sucrose Induced Dentin Demineralization in a Microcosm Biofilm Model

“…These SHL results have been demonstrated in previous studies (Steiner-Oliveira et al, 2011;Cury et al, 2000), confirming that dental biofilm formed after exposure to sucrose has high cariogenic power. However, those studies used a different methodology, making it difficult to compare them with this study.…”

“…This can be explained by the presence of meat extract, yeast extract, proteosepeptone and porcine gastric mucin in the artificial saliva medium (Pratten et al, 1998;Steiner-Oliveira et al, 2011), which might have been used as nutrients. Porcine gastric mucin is used as a substrate for saliva due to its similarities with the structure of oligosaccharides of human mucin saliva, which in turn, has been associated with the development of caries in the absence of other sources of nutrients (Kolenbrander, 2011).…”

“…Different biofilm models display a practical and ethical way of exploring new opportunities to investigate and fight dental caries (Salli & Ouwehand, 2015). The most frequently used biofilm models are: the single species (Steiner-Oliveira et al, 2011), the multi-species consortia (Shu et al;Yang et al, 2011) and the microcosm (Filoche et al, 2007;Azevedo et al, 2011). The microcosm is a laboratory system derived from natural ecosystems, where over 700 species of bacteria coexist.…”

Evaluation of caries-affected dentin with optical coherence tomography

“…5 In the chemical method, the acidified gel technique and pH-cycling method are included; in contrast, microorganism strains with known cariogenicity are used in the microbiological method in a way whereby the acid product of their metabolism demineralizes the dental structure. 5 More elaborate systems involving chemostats, flowcells, artificial mouths, and constant-depth film fermentors have been developed in an attempt to better mimic the environment of the oral cavity. 5 However, their high cost and complex apparatus requirements are often limiting factors.…”

Laser Technology for Caries Removal

“…In the chemical method, the acidified gel technique and pH-cycling method are included; in contrast, microorganism strains with known cariogenicity are used in the microbiological method in a way whereby the acid from bacterial metabolism demineralizes the dental structure (Steiner-Oliveira et al, 2011). More elaborate systems involving chemostats, flowcells, artificial mouths, and constant-depth film fermenter have been developed in an attempt to better mimic the environment of the oral cavity.…”