When it comes to family genetics, traits such as eye colour and blood type are passed down through your parents, but what about characteristics associated with your mouth and teeth?

The answer is that while some traits can be inherited or influenced by genetics, much of your dental health is within your control. 

“Our genes do play a part but more importantly, it’s the interaction between genetics and lifestyle and environmental factors which is the key to maintaining a lifetime of oral health and wellbeing,” says Dr Greg Thomas, a dentist at Bupa Dental in Rochedale, Queensland. 

We asked him to help us break down the nature versus nurture relationship.

Tooth decay

We can blame our parents for many things, but tooth decay isn’t one of them. A Melbourne study looked at the teeth of 173 sets of twins from pregnancy through to six years of age and found that identical twins, with identical genomes, had varying degrees of decay. Lead researcher Dr Mihiri Silva wrote: “This means that environmental factors, like a lack of fluoride in water, seem to be the prime cause of cavities not genetic makeup.”

However there is a family component that can make you more susceptible to tooth decay, says Dr Thomas, and it’s not in your genes

“It involves the oral microbial flora,” he explains. “Just like our gut, the mouth contains good and bad bacteria. Only a select type of bacteria (e.g. streptococcus mutans) can cause tooth decay and a person with a high level of these bacteria has a greater risk of tooth decay." 

“Oral microflora development is heavily influenced by family – close contact among family members leads to sharing their oral microflora, especially from parents to children.”

Gum disease

Gum disease is a serious infection of the tissues that hold your teeth in place. It can cause redness, swelling and bleeding of the gums, and without proper treatment can lead to tooth loss. The main cause of gum disease is a build-up of plaque, a substance containing bacteria which can harden under your gum line into tartar, and needs professional dental cleaning to be removed.

The best way to prevent gum disease is to practise good oral hygiene and visit your dentist regularly, but there are risk factors which make some people more likely to get periodontal disease (the advanced stage of gum disease), including genetics.

“Although gum disease is a bacterial infection, a person’s susceptibility and severity of the disease is influenced by our genetic inheritance,” says Dr Thomas.  

Other risk factors include:

• Age
• Smoking 
• Stress
• Medications
• Clenching or grinding your teeth
• Poor nutrition 
• Obesity.

Tooth colour

“Just like your eye and hair colour, the colour of the teeth you are born with is predetermined by genetics. However, the shade, tone and hue are uniquely your own that vary from one person to another,” says Dr Thomas. 

So you may or may not have similar teeth colour to your parents or siblings. 

However, environmental factors – especially lifestyle factors – can significantly influence teeth colour. 

“Whether we smoke, or drink coffee, tea and red wine can discolour our teeth,” Dr Thomas says. “Certain medications can darken the tooth structure. These environmental changes to teeth colour and shade are why tooth-whitening procedures  are so popular.” 

Tooth alignment

Crooked, crowded or gappy teeth do have some genetic component, says Dr Thomas.

“Many malocclusions (bad bites) and jaw profiles commonly causing teeth crowding and jaw-alignment issues are inherited genetically, but genes are not the sole cause,” he says. “Enlarged adenoids, nasal obstruction caused by allergies, chronic mouth breathing and poor tongue posture can also lead to teeth and jaw-alignment problems.”

In short, our inherited genes do play a part in our oral health and susceptibility to dental problems. But the advice from your dentist is still the same; limit sugary foods and drinks, brush and floss regularly, and have regular dental check-ups.

Talk to a dentist near you

If you have any further questions, chat to your nearest Bupa dentist.