By Susan Richards
With the advent of home DNA tests, it’s become easier to connect the dots to our genetic past. Not only can we find that forgotten “sketchy” relative, but the testing can uncover genetic risk factors for medical issues in a family tree that can impact one’s own health.
The same, however, may not be true in tracking down oral health problems – yet.
It’s in the Genes
Our cells are made up of 23 pairs of chromosomes with DNA contributed (nearly equivalent) by both biological parents. Each of those chromosomes contains thousands of gene sequences that are active or dormant depending on various factors, such as environment. The combination of those genomes may result in genetic anomalies that influence certain physical attributes or medical conditions.
Dentists have heard for years that poor oral health is the result of “bad luck” in the gene pool. While there may be a modicum of truth there, it’s more complicated than that. There are definitive genetic abnormalities that can arise during tooth development, which spans from a month into the gestational process to the eruption of the wisdom teeth – around age 19. These congenital defects include:
- Anodontia – The complete absence of teeth in development.
- Hypodontia – A common genetic abnormality that leaves one to five teeth missing, typically second premolars and lateral incisors.
- Dentinogenesis Imperfecta – A translucent appearance or tooth discoloration.
- Amelogenesis Imperfecta – Missing or defective tooth enamel.
- Cleft Lip and Palate – A malformation during fetal development where the palate and/or lips don’t fully connect.
While they don’t directly involve the mouth and teeth, genetic conditions such as Down Syndrome, Mohr Syndrome, and Apert Syndrome can impact oral health.
Crowded and misaligned teeth can be attributed to the family tree in inherited jawlines, overbites, and underbites. Oral cancers are much more likely to be a result of lifestyle choices such as tobacco use, but genetic markers that predispose a patient to cancer can increase the risk.
The Blame Game
When it comes to the most common conditions that dentists work with every day, new research shows it’s become more difficult to blame tooth decay and gum disease on genetic influences than before.
In one such study, researchers at the J. Craig Venter Institute looked at the oral microbiomes of 485 young twins, identical and fraternal, to determine the hereditary factors. They concluded that while oral bacteria are heritable, it’s ultimately not the main influence on the caries state. Researchers were also surprised to learn that the inherited bacterium in the mouth diminishes over time.
Likewise, a 2019 study at the University of Melbourne on 173 sets of twins found that genetic makeup has little to do with tooth decay. In fact, lead researcher Dr. Mihiri Silva stressed the importance of not blaming DNA for dental issues, saying, “If people think the health of their teeth is down to their genetic make-up, they may not be prepared to make important lifestyle changes.”
However, periodontal disease may have more of a genetic component, according to an overview by the LSU School of Medicine, Department of Genetics. Like caries, it’s caused by bacteria found in dental plaque but impacts the gums and bone, and mainly in adults. External factors such as smoking, oral hygiene, and age can increase or decrease the severity of gum disease.
Diabetes, a complex disease that affects the whole body, can have a strong link to family history – especially Type 2. Diabetic patients have a greater risk of periodontal disease as a result of poor blood flow, as well as other oral conditions like thrush and dry mouth. Inversely, children with diabetes show a decrease in tooth decay thanks to low sugar diets.
There are many attributes we may credit to various branches of the family tree, like freckles or foot size. However, research is continuing to prove that the number of cavities patients present with can’t be blamed on genetics. A comprehensive article on genetics and oral health by the American Dental Association agrees that many common diseases aren’t inherited, but are more a result of gene-environmental interactions.
Taking a patient’s health history into consideration is still important, but until there’s a predictive genetic test for caries and gum disease, continuing to urge preventative care is the best path to optimum oral health in patients.
Author: Susan Richards is a staff writer at DOCS Education. With over 20 years of experience in local journalism and business marketing, Susan’s career includes award-winning feature writing, as well as creating content with context for a wide variety of industries.