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Title: 0216 - Ovalbumin Anticariogenicity of Streptococcus mutans and Streptococcus sanguinis Dual-species Caries-model

Authors:

Rodrigo Giacaman (Presenter)
University of Talca

Angela Alarcón, University of Talca
Carla González, University of Talca
Natalia Díaz-Garrido, University of Talca

Abstract:

Objectives: Our group has previously demonstrated an anticariogenic potential of egg ovalbumin. Mechanisms involved remain uncertain, but an ecological effect on the competition of cariogenic and commensal species seems plausible. The aim, therefore, was to explore the outcomes of ovalbumin exposure under cariogenic conditions on the competition and cariogenicity of a dual-species biofilm with different inoculation sequences.

Methods: A dual-species caries-biofilm model with Streptococcus mutans UA159 (Sm) and Streptococcus sanguinis SK36 (Ss) was designed. Enamel slabs covered with saliva were allocated to 4 inoculation sequences: 1) Ss followed by Sm (Ss-Sm), 2) Sm and Ss inoculated at the same time (Sm=Ss) and the controls 3) Sm followed by Sm (Sm-Sm) and 4) Ss followed by Ss (Ss-Ss). Once mature, biofilms were exposed to 10% sucrose followed by 1 mg/mL of egg ovalbumin, 0.05% NaF or 0.9% NaCl (caries-positive control), 3 times/day for 5 days. Acidogenicity and demineralization by Knoop microhardness were assessed and biofilms analyzed for biomass, polysaccharide formation and bacterial cell counting. Two independent experiments were carried out, in triplicate (n=6). ANOVA followed by Tukey allowed statistical comparisons at p-value<0.05.

Results: Biofilms exposed to ovalbumin resulted in an overall reduction of around 60% in acidogenicity and demineralization, regardless of the inoculation sequence. When Ss was the first colonizer (Ss-Sm), this reduction was higher than in the Sm-Sm control (p<0.05), and even lower than that induced by 0.5% NaF. No statistical differences were observed in biomass and polysaccharide formation across the samples. Compared with the sucrose-only condition (caries-positive), ovalbumin-treated biofilms showed less Sm viable cells when Ss was the first to colonize the enamel (Ss-Sm) (p<0.05).

Conclusions: The anticaries effect of ovalbumin appears to be confirmed by creating conditions favorable for commensal competition over cariogenic species. In vivo experiments seem needed to confirm these findings in the dental biofilm.

This abstract is based on research that was funded entirely or partially by an outside source:
Funded by the Chilean Government Grant Fondecyt #1140623 to RAG.

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: None

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