Every six months or so a checkup at the dentist results in the news of new cavities or a perfectly clean mouth, which often appears to reflect one’s attention to oral hygiene. If the news is new cavities, reflecting on how detailed one was with their daily regiment and advice from the dentist generally ensues. I recently went to the dentist and was told that I have a cavity on one of my molars which was very surprising because I floss and brush my teeth every single day. This lead me to question what other factors come into play with oral hygiene (besides diet). Knowing that my father has a very unfortunate history with his many tooth-related ventures, I wondered whether or not cavities are merely genetic phenomena and if, even though I floss and brush every day, I’m bound to have oral hygiene troubles.
A study contributed to by many institutions, including the J. Craig Venture Institute, examined the presence of oral microbial bacteria in 485 twins from age 5-11 via mouth swabs. Twins of both dizygotic and monozygotic types appeared, to increase the range of similar genotypes and thus the specificity of the results. Caries, age, and sugar are three factors that were in consideration as a cause of increased bacteria, as shown below. The image below also represents a basic separation of the heritable and environmentally-determined bacteria in the subjects who were more and less similar.
In bacteria that were highly heritable, age, sugar, and caries appeared to increase with decreased bacterial presence, showing a negative correlation. In bacteria mainly modulated by the environment, caries seemed to increase as the abundance of bacteria increased. In other words, the environment has a large impact on the number of bacteria and therefore carries within the mouth, but in cases of heritable bacteria, an increase of age and a decrease of sugar intake will decrease the damaging effects that bacteria can cause. Also, heritable bacteria appear to not have a relationship to caries present in the mouth. All in all, the study found that
1. Heritable oral bacteria do not cause or lessen the existence of caries. 2. Environmentally-derived bacteria, from one’s diet, for example, do impact the presence of caries and often remain similar in number between genetically similar individuals. 3. With age, heritable bacteria may decrease.
“Thus, while the human oral microbiome composition is influenced by host genetic background, potentially cariogenic taxa are likely not controlled by genetic factors” (Cell Press 2017).
In conclusion, the Cell Press study shows that heritable oral bacteria is, in fact, genetic, but has no clear relationship with the presence of cavities and can decrease as one ages. Therefore, having misfortunes with my oral hygiene is partially genetic, but the presence of heritable bacteria that I have will decrease over time and does not cause cavities. It’s my environment (i.e. diet) that most heavily influences my oral hygiene state. Knowing that cavities can’t be blamed on genetics, more caution should be taken when choosing what foods to eat (sugar, carbohydrates, etc…) that could potentially be cariogenic.
*Caries = cavities
References:
Gomez, Andres, et al. “Host Genetic Control of the Oral Microbiome in Health and Disease.” NeuroImage, Academic Press, 13 Sept. 2017, http://www.sciencedirect.com/science/article/pii/S1931312817303463.
Data/Society/Decision-making Spring 2019 