Reversal of Dental Caries

While 96% of the tissue that comprises dental enamel is largely mineralized, an organic protein matrix contributes to the remaining 4% (Rathva, 2011). These proteins, produced by ameloblast cells during early teeth development, come together and become insoluble at physiologic pH and temperature in the mouth, forming the scaffold that supports the hard mineral layer as it is deposited onto the matrix (Joseph et al., 1999). The strength and stability of healthy teeth is reliant on the structural relationship between the hard mineral layer and support from this protein scaffolding.

Dental caries occur as a result of demineralization, where extrinsic elements such as an acidic environment from bacterial lactic acid fermentation cause the hard mineral layer of teeth to dissolve into solution and be washed from the protein matrix. It is often cited that dental caries are progressive and irreversible following onset because once this protein matrix is exposed and damaged, it does not regenerate. This is because the cells that form these proteins undergo apoptosis (programmed cell death) following teeth development (Joseph et al., 1999). As the protein matrix is permanently lost once it is degraded, reversal of dental caries and regeneration of affected/lost tissue after onset is often not a viable strategy. Instead, modern treatments involve methods to arrest further progression of disease into healthy dental tissue by removing the diseased tissues affected by pathogenic bacteria.

However, there has been increasing interest in research for alternative treatments of dental caries to preserve tissues and improving patient outcomes. The use of biomimetic peptides, proteins that are designed in labs to resemble natural proteins such as those produced by ameloblast cells, is one particular area of interest. While traditional treatments such as water and toothpaste fluoridation and sealants against acidic compounds are designed to minimize demineralization and thus reduce the incidence of disease (how many people get dental caries), the application of these proteins instead target the reformation of the protein matrix to reduce the prevalence of disease (how many people continue to suffer from dental caries). Although the cells that naturally produce the supporting protein matrix in enamel die soon after the tooth develops and erupts, if dentists are able to recreate the protein matrix that scaffolds teeth remineralization and apply it to affected sites, they could potentially reverse disease following onset and reform dental tissues (Firth et al., 2006).

It is important to consider the ethics involved with the availability of such a treatment with respects to justice and equal availability of a treatment. According to the American Dental Association, as of 2014, only 74.4% of Americans have access to fluoridated water (2018). Although community water fluoridation has been considered largely successful public health policy, one should realize the complexity of the infrastructure necessary to provide such a service. For communities that do not have the funding to support this infrastructure, it is reasonable to conclude that these patient populations (who likely suffer from higher incidences of dental caries) would also not be able to access treatments such as biomimetic proteins should it become available.



References:

American Dental Association. (2018). Fluoridation Facts. Retrieved from https://www.google.com/books/edition/Fluoridation_Facts/_p1qDwAAQBAJ?hl=en&gbpv=1

Firth, A., Aggeli, A., Burke, J.L., Yang, X., Kirkham, J. (2006). Biomimetic self-assembling peptides as injectable scaffolds for hard tissue engineering. Nanomedicine, 1(2), https://doi.org/10.2217/17435889.1.2.189

Joseph, B.K., Harbrow, D.J., Sugerman, P.B., Smid, J.R., Savage, N.W., Young, W.G. (1999). Ameloblast apoptosis and IGF-1 receptor expression in the continuously erupting rat incisor model. Apoptosis, 4(6), 441-447, DOI: 10.1023/a:1009600409421

Rathva, V.J. (2011). Enamel matrix protein derivatives: role in periodontal regeneration. Dovepress: Clinical, Cosmetic and Investigational Dentistry, 3, 79-92, doi: 10.2147/CCIDEN.S25347