We are all the successful end-products of amazing human genetics. Genes determine how we develop, grow and look. They determine facial shape, jaw sizes, muscle form, tooth positions and size. A combination of genes from our parents make us who we are and we, in turn, will pass these on to the generations to come. This is why family members look similar.

Jaw Size and Shape

An individual’s jaw size and shape are predominantly determined by genetics. Many members of the Habsburg family (Hungarian-Austrian royalty), had abnormally large lower jaws and ‘underbites’. Underbites are also commonly found in Asian families. In contrast, long faces and smaller lower jaws are relatively more common in Anglo-Saxon populations. Think of Prince William! Strong familial traits are good examples of genes controlling form.

An unfavourable genetic combination can create a large discrepancy in upper and lower jaw sizes, often causing the teeth to be poorly positioned. Fortunately, modern orthodontic treatment can successfully correct very severe facial structure problems and bites.

Number of Teeth

Most humans have 32 permanent teeth. Five percent of the population are missing permanent teeth. When a patient has missing permanent teeth, 50% of their siblings or parents are also missing permanent teeth, indicating a strong genetic link. Orthodontic treatment can close missing teeth spaces, disguising the fact that any teeth are actually missing! This avoids the need for false teeth, which is especially beneficial at the front of the mouth.

Similarly, the presence of extra teeth (i.e. supernumerary teeth), is also genetically determined. Supernumerary teeth are found in approximately 2-3% of the population and can disrupt the normal eruption of other teeth. Early detection and their timely removal will minimise such disturbances.

Crowded Teeth

Like jaw sizes, tooth sizes are strongly linked to genetics. Dental crowding is more severe if a patient has inherited a combination of small jaws and large teeth. Thankfully, even the most severe forms of dental crowding and tooth malposition can be predictably corrected with orthodontic treatment.

Environmental Factors

While most dentofacial features are determined by genes, factors outside of genes can also affect the teeth and face. These are referred to as ‘environmental factors’. The most common example is a thumb-sucking habit, which can cause protrusive upper teeth and a narrow upper arch. Ideally, thumb-sucking habits should be stopped before the permanent teeth erupt. Thankfully, if the teeth are very displaced, well-provided orthodontic treatment can still correct the dentition.

What does this mean for my child?

When it comes to facial development, genetics is king! This means that it is often very difficult or even impossible to alter and change the growth direction that has been pre-programmed by genes. Therefore the use of simple plates, breathing or muscle exercises CANNOT be expected to STOP the development of most orthodontic problems. However, orthodontics can predictably CORRECT dentitions within the genetically determined framework of the face. An Orthodontist can predictably correct dentofacial anomalies that are caused by both genetic and environmental factors.

If your child is developing unusual dentofacial patterns, please see your specialist Orthodontist soon. The quality of your orthodontic result is dependent on your practitioner’s understanding of the facial form and their ability to apply proven techniques that are supported by high quality evidence. Only an Orthodontist has the training, experience and expert knowledge to accurately determine what is normal, what is not, and everything in-between.

Townsville Orthodontic Specialists
17 Martinez Avenue 
The Lakes Townsville
4775 4433
admin@tsvortho.com.au
www.tsvortho.com.au