The Straight Facts About Crowding

So, why do most of us experience crowding of our teeth at some point in our lives?
The answer to this question can be both simple and complex – intertwining evolution, heredity, and environment.

Evolution. Our teeth are catching up.

The prevalence of dental crowding in the US population is estimated at 66%. Interestingly, an analysis of human skulls from 10,000+ years ago shows almost no evidence of crowding or impacted teeth – including those pesky wisdom teeth. Why the difference between then and now? The reason for these ideal prehistoric arches is due to the diet of the cavemen.

Early humans needed powerful jaw muscles and consequently large jaws to masticate their raw food. Also, the course diet caused teeth (in their respective arches) to wear against one another thus negating crowding with age. Over the millennia, tools were introduced, hunter-gathers shifted toward an agrarian society and diets became softer. The need for powerful jaw muscles diminished and jaw size shrank – unfortunately, tooth size stayed about the same. As a result, the prevalence of crowding began to increase. This trend continues today with our modern society and our processed food.

No wonder most of us don’t have enough room for our wisdom teeth!

Genetics at work

In addition to this evolutionary trend, a large factor that plays into whether we as individuals have crowded teeth is the role of genetics. Both tooth size and jaw size are inheritable traits. Our parents contribute genetic material that influences how large our teeth will be and the size of our jaws. In the worst-case scenario, one parent passes along the gene for large teeth while the other parent passes along the gene for small jaws. The result: Lots and lots of crowding! In a situation like this, the normal complement of 32 teeth must be reduced to 24 teeth (by extracting the first bicuspids and third molars) to accommodate the remaining teeth.

Thank goodness for orthodontics!

What’s the environment got to do with it

A final factor that plays into crowding is environmental influences. This is the largest contributor to crowding and the one that we have the most control over. As children, different situations can result in early crowding or set the table for future crowding. Some examples are early loss of baby teeth without the placement of a space maintainer, an ongoing habit like thumb sucking resulting in the tipping back of lower incisors, failure to address ectopic (out of position) or impacting adult teeth, allowing baby teeth to be over-retained, and not expanding narrow arches in advance of permanent tooth eruption.

Different situations can set the table for future crowding. Thumb sucking is one of them.

Time can be tricky

One question that always comes up in regards to crowding is the role of third molars. Especially since many of us have perfectly straight teeth until our late teens or early twenties. A significant number of studies have been done on the correlation between wisdom teeth and crowding. A systematic review of the literature published in The Scientific World Journal showed that third molars are not the culprit in lower anterior crowding. So what is going on? Over time, there are subtle changes that occur which collectively result in a breakdown of the alignment of the teeth. Most changes begin in the lower arch and ultimately show up in the upper arch since the lower arch can act as a mold or “retainer” for the upper arch. Typically what happens with age is that the lower arch narrows especially by the canines, the lower molars slowly move forward and the arch length decreases. With these movements, something has to give and it usually starts with crowding of the lower incisors.

Don’t worry, take action

All hope is not lost! If you are a parent of a young child, be proactive and have the dentist monitor your child’s dental development. Don’t be afraid to seek an orthodontic evaluation if you have concerns. You don’t need a referral and exams are complimentary. If you have already been through orthodontic treatment – keep wearing your retainers. Remember, it is a lifetime commitment if you want to keep your teeth straight. If you are an adult and experiencing shifting of your teeth, don’t wait – the crowding will only worsen with time.

If you have questions about the benefits of Invisalign treatment, please call Visage Orthodontics at 505-670-6145 or visit our appointment page to schedule a complimentary consultation with me, Dr. Tanner, your Santa Fe Invisalign specialist. I will review everything in detail and develop a customized treatment plan to fit your lifestyle and budget.


A confident and beautiful smile is right around the corner!