Are teeth more crowded today than in the past? Why do so many people "need" braces today?

Contemporary Orthodontics & Dentofacial Orthopedics

James R. Waters, DDS, MSD, PA

Board Certified Treatment for Children, Teens and Adults  

Are teeth more crowded today than in the past?

Why do so many people “need” braces today?

These are interesting questions and I will try to answer to the best of my knowledge with the caveat that some of this is conjecture and some based on research in the literature.  This is meant to be more for thought provocation and is not meant to offend any particular group or population.

I have often marveled when the National Geographic publishes the discovery of some previous population of our ancestors and they show skulls with fairly straight teeth.  As an Orthodontist, it always make me think on why we have so much crowding in our population when previous people seemed not to be inflicted with as severe malocclusions.  But there are a few answers that will explain this conundrum.

First, there is academic debate that our diets were rougher in the past including more grains and seeds; this presumably led to inter-dental wear which relieved crowding by not allowing pressures to build up across the dental arch throughout life.  Since we know teeth naturally drift forward in the mouth, if we figure the interproximal surfaces are being reduced over time, teeth get smaller and fit better in the arch.  We actually use this same idea when treating some patients and even during retention following orthodontic treatment.  By reducing between teeth, we can align the teeth into a smaller arch form which prevents teeth from rotating or crossing over (this is routinely performed with clear aligners to correct crowding and limit expansion of the arches which is unstable and relapses following treatment). 

But this is only part of the equation.  The bigger picture is that there were smaller gene pools or less population diversity in the far past.  Since everyone within a tribe or region was descended from a more recent common ancestor, they shared more genetic similarities therefore the size of the teeth matched the size of the bone better.  As well, we can think in terms of natural selection since we know severely crowded teeth would lead to more significant chances of dental infection which would lead to a higher morbidity (bad teeth led to poor health causing a higher morbidity which selected against this trait or genetic expression).

This evolutionary theory is evident with wisdom teeth as earlier humans had more protrusive faces which provided larger arches for teeth; one can measure and see that the teeth on these older humans resemble the same size as ours.  As we walked more upright, our faces became flatter, shortening the arches for teeth.  Wisdom teeth became more of a liability and began to cause “ripples” in the gene pool hence now the most commonly missing tooth is a wisdom tooth (or wisdom teeth).  Of course dentists and oral surgeons have learned to remove teeth before a mortal infection takes over so there is no more genetic selection against those with impacted wisdom teeth in recent and modern civilization (I would surmise this is similar to poor vision now being corrected with glasses and allowing weaker vision to pass on without being selected against in the gene pool).

If we test this hypothesis against an ancient and unchanged population, the Australian Aborigines for example, we see malocclusions less frequently as there is a common lineage with less variation; evolution has selected against severe dental crowding and this has remained unchanged for thousands of years.  Not until recently have new genes been re-introduced which represent dis-similar facial patterns but as more Western European genes are introduced with the Aborigine population, genetic variation is increased and we are more likely to see either spacing or crowding not previously common for that population.  So applying this theory to a larger population over greater time, (i.e. the accelerated mix of genes as the Europeans colonized their continent and mixed in with other populations) and you can see how easy it is to inherit different features from different backgrounds.  Although diets have changed significantly in recent times, I personally see this natural selection as being the more likely culprit to the increased frequency and severity of modern malocclusions.  Of course this same genetic variation due to increased gene pools with greater diversity also provides greater protection for humans to resist outbreaks of pathogens making it more difficult for a single pathogen to wipe out entire populations as so vividly imagined on television today.    

As for these more frequent malocclusion today, I for one am thankful there is a profession that has learned to competently straighten teeth and can provide us all with beautiful and functional smiles for a lifetime of good health even when one’s teeth do not exactly fit together or fit the size of one’s jaws.

If you have questions or comments concerning this or any orthodontic question, please feel free to make a complimentary new-patient appointment at either my Steiner Ranch location or my North-central Austin location on West 35^th street and MoPac.

Dr. James R. Waters is a 1996 graduate from UTHSC Dental School in San Antonio, 1997 graduate of Advanced Dentistry from the UNMC in Nebraska and the 2001 Valedictorian graduate from the prestigious Saint Louis University Orthodontic Program receiving the J.P. Marshall award for clinical excellence in 2001.  He holds a Bachelor’s Degree in Science, Doctorate in Dental Surgery, a post-doctorate certificate in Advanced Dentistry, post-doctorate Degree in Orthodontics & Dentofacial Orthopedics and a Master of Science Degree in Orthodontics.  Dr. Waters and his wife of 19 years live in Austin, TX with their 4 children where he has a thriving, multi-faceted Specialist practice with locations in Steiner Ranch and North-Central Austin.  You can learn more about Dr. Waters at BracesAustin.com.  

Central Austin

1814 W. 35^th Street

Austin, TX 78703

(512) 451-6457

 

 

Steiner Ranch

4302 N. Quinlan Park

Austin, TX 78732

(512) 266-8585

 

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