Oral Candida infection weakens tooth enamel

Feb 11 2013

By Joanna Lyford, Senior medwireNews Reporter

Oral infection with Candida albicans is associated with demineralization of tooth enamel, potentially increasing susceptibility to caries, research shows.

As the study was conducted in a child with HIV infection, the findings could potentially explain how the virus accelerates the cariogenic process, say Gloria Castro (Cidade Universitária, Rio de Janeiro, Brazil) and fellow researchers.

Castro et al hypothesized that since C. albicans has a high acidogenic potential, infection with the pathogen could contribute to the demineralization of tooth surfaces. Furthermore, the prevalence of C. albicans in dentinal tubules is higher in HIV-infected than non-infected individuals.

To investigate, the team obtained histologic samples from the oral mucosa and enamel blocks from a dentin carious lesion from a HIV-infected child; enamel blocks from 10 healthy molars served as controls.

The enamel blocks were then exposed to C. albicans biofilms isolated from either carious lesions or mucosa or to no biofilm (control).

Results, published in Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology, show that biofilm exposure led to a reduction in enamel strength, as indicated by measurement of cross-sectional microhardness (CSMH).

The reduction in enamel microhardness became significant by day 3 for samples exposed to C. albicans from the mucosa and by day 5 for samples exposed to C. albicans from carious lesions. By day 10, enamel microhardness had fallen by 43.90%, on average, for samples exposed to mucosal C. albicans and by 53.19%, on average, for samples exposed to carious C. albicans. The between-group difference was not statistically significant. In the control group, enamel microhardness was unchanged throughout the 10 days of the experiment.

Finally, there was no change in cellular viability throughout the experiment in any of the three groups.

Castro and co-authors note that dental caries are highly prevalent in HIV-infected children and that caries should be considered a risk factor for Candida colonization and oral candidiasis in this population.

"Collectively, these findings indicate that this yeast may cause demineralization and it could be a cohelper in cariogenic development," they write.

"Considering the high prevalence of caries in HIV-infected children, further research to elucidate the predisposing factors of this disease in this population would be very useful."

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