Mu-can: A bacterial-fungal symbiosis that reduces dental caries

Dear Editor,

Dental caries is a significant public health problem, and the concept of reducing caries initiation is the most superior method of controlling it. Researchers are always exploring breakthrough technology for caries prevention. Philip et al.[1] have proposed an exciting concept called Ecological Approaches to Dental Caries Prevention. It includes specifically targeting cariogenic bacteria without affecting other resident microflora, inhibiting virulence factors (e.g., glucan synthesis or acid production) rather than bacterial viability, and enhancing colonization of health-promoting microbial communities, which will correct the ecological imbalance in cariogenic biofilms. As against this background, the authors wish to present an unconventional caries preventive concept.

PROOF OF CONCEPT

Candida albicans (C. albicans) is one of the components of normal oral microflora, and only when there is an imbalance in the normal flora is there an outgrowth of this organism and leads to pathogenesis. Streptococcus mutans (S. mutans) are responsible for the initiation of dental caries. It is found that the bacterial-fungal association of S. mutans and C. albicans is extremely co-operative; both are exceptionally acid-tolerant organisms and can efficiently adhere to teeth enamel.[2,3] Based on this co-operative symbiosis, unique and noteworthy concept for dental caries prevention through an ecological approach is hereby proposed.

Let us consider Mu-Can as a dual species biofilm of S. mutans and C. albicans formed by the application of a dental varnish containing C. albicans applied on the teeth. On the tooth surface, Mu-Can will have the following mechanism of action:

1. Generally, S. mutans which received greater sucrose availability in the mono-species biofilm[4] will now have reduced amount due to competition from C. albicans in the dual-species biofilm

2. C. albicans will metabolize the available sucrose or other sugars into ethanol instead of lactic acid.[2] Thus, the pH of the environment will not become acidic

3. The lactic acid formed by S. mutans will be consumed by C. albicans as a carbon source for energy[5] and thus, this will cause alkalinization within the biofilm and help in reducing enamel demineralization.

Basis, these three suppositions with literature support,[2,3,5] Mu-Can can prove to prevent acidic environment, reduce enamel demineralization and thus prevent caries initiation [Figure 1.]

Figure 1.

Schematic diagram of Mu-Can mechanism. (a) Mono species of Streptococcus mutans (Mu) produces acidic environment favoring demineralization. (b) Dual species of Streptococcus mutans and Candida albicans (Mu-Can) causes alkalinization of environment and reduces demineralization)

Further, to confirm the effectiveness of caries inhibiting the action of Mu-Can, we propose an investigation using the in-vitro dual biofilm model to assess the change in the pH of the micro-environment, calcium release from enamel, surface micro-hardness, and estimation of colony-forming units (cfu) of S. Mutans and C. albicans. Furthermore, investigation will have to be carried out to ascertain the minimum cfu of C. albicans required without getting affected by its virulence, if any. Once we have the positive confirmation, a Mu-Can dental varnish can be proposed based on this concept. The varnish can be applied to the teeth through the “Paint on” application by the person at home and will not need any professional intervention. If Mu-Can symbiosis hits as an ecological approach for caries prevention, it will be a landmark research in reducing dental caries.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.