The Evolution of Human Dentition

The impact of diet in the microbes on teeth

Human diet has evolved throughout time. This evolution has completely changed the human microbes on teeth. Humans have increased in regular diets carbohydrates which in turn increases cariogenicity (Cornejo et al., 2013). The constant supply of carbohydrates aid in the cause of diseases which in turn require the human body to adapt. Additionally, the transition from gathering to agriculture allowed to the exponential population expansion of streptococcus mutants (Cornejo et al., 2013). This major shift restructured the microbial ecology of humans. The change went from balanced highly diverse microbes to a low-diversity acid dominant microbes (Adler et al., 2017). Figure 1, provides a good example of how human diet and intervention directly affects the human microbe in teeth. A diet low in carbs can help inhibit production of glucans which prevents the formation of cariogenic films (Baker et al. 2019). Understanding the complexity of a system with native microbes that fight with colonizers is important to observe how the human body can adapt (evolve) to changes in its environment.

Wanda
Figure 1 Shows how a healthy tooth can develop caries. Main reason is due to poor oral hygiene but “fuel” to the fire can be attributed to high-sugar diets. The Figure also demonstrates why it is more common to develop caries in contrast to the poor-hygiene from the past.
Wanda
Figure 2 a) shows how as human history reaches “modern” times, the population of S. mutants exponentially evolved. b) shows how it was observed in the S. mutants evolution the behavior of an exponential growth. The lower the allele, the more “rare,” the higher the number of segregating sites, means the more diverse the evolution is. Essentially showing how the S. mutant had an observation of an exponential population. C) shows the areas where there was a likelihood for the exponential growth of S. mutants. The x axis is the normalization of the current population to the ancestral population while the y axis denotes the time since expansion. These figures show that after modernization (which included change in diet), the S. mutants evolved fast which in turn forced the microbials in the human teeth to evolve as well.