Upon examining ancient skulls, one striking feature is their perfectly straight teeth. This is not an anomaly, but a consistent trait found in the fossil record of ancient humans. They typically had straight teeth, including third molars or wisdom teeth. This is in stark contrast to the modern human condition where dental issues such as crooked teeth and impacted wisdom teeth are common. So, what happened to cause this shift?
While it’s difficult to pinpoint the exact cause, scientists have a hypothesis. A couple of million years ago, the ancestors of modern humans lived a subsistence lifestyle. Their teeth and jaws had to work hard to make their food digestible. This is evident from the extensive wear and flattening seen on the surfaces of their teeth. They also had larger jaws and teeth overall.
Over time, these early humans began using tools and fire to cook and prepare food, which helped break it down. Around 12,000 years ago, some humans started farming and domesticating animals and plants. Over several thousand years, it became more common for people to process and refine their food. Milling technologies helped remove the tougher parts of grains, like the germ and bran from rice and wheat.
Fast forward to the Industrial Revolution, and technological innovations dramatically accelerated these processes. In a relatively short time, many human mouths were relieved of their grinding, crushing, and pulverizing duties. Interestingly, it was around this time that tooth crookedness appears to have become more common.
Examining fossils spanning millions of years of evolution, researchers have observed a gradual decrease in tooth and jaw size in humans and our ancestors. Many believe that for most of human history, dietary shifts, like the introduction of meat and the advent of cooking, were gradual, and changes in tooth and jaw size basically kept pace with one another. But with the more recent revolutions in agricultural and culinary habits, that relationship changed.
As the theory goes, over a relatively short period, some human populations saw a decrease in jawbone size, while teeth stayed roughly the same size. This meant that teeth were left vying for limited space. When they did grow in, they may displace others and get jostled into some eccentric positions. Wisdom teeth, which are usually the last to make their debut, seem to only complicate things further. In many cases, they have little or no space to emerge, leading to impacted wisdom teeth, which may cause discomfort and infections if not surgically removed.
So, larger jaws appear to be associated with greater chewing demands. Many scientists think that as people’s diets have become less chewy, their jaws have gotten smaller, leading to dental crowding, resulting in dental crookedness and impacted wisdom teeth.
This hypothesis has been supported by some preliminary experimental data. For instance, a 1983 study found that squirrel monkeys raised on diets of softer food had more crowded premolars, rotated or displaced teeth, and narrower dental arches. A 2004 study similarly observed that hyraxes raised on cooked foods experienced roughly 10% less growth in facial areas involved in chewing compared to those given raw and dried foods.
It’s estimated that somewhere between 30 to 60% of people today experience some level of tooth crowding. However, this trend varies across global populations. Some people naturally never have wisdom teeth. Some don’t experience tooth crowding or crookedness and still get their wisdom teeth without a hitch. This seems to coincide with diets that are less processed.
So, how can we prevent tooth crowding early, using lifestyle changes and orthodontics? Well, it’s certainly something to chew over. The issue at large seems to be environmental or one of lifestyle, instead of a genetic one, though heritable factors may be at play in some instances.
Investigate the diets of ancient humans and how they differ from modern diets. Create a presentation that compares the types of food, preparation methods, and the impact on dental health. Include visuals such as charts and images of ancient tools and food items.
Participate in a class debate on the pros and cons of processed foods. Divide into two groups: one supporting the convenience and benefits of processed foods, and the other arguing for the health benefits of natural, unprocessed foods. Use evidence from the article and additional research to support your arguments.
Create a 3D model of the human jaw and teeth using clay or other craft materials. Highlight the differences between ancient and modern human jaws and teeth. Label each part and explain how changes in diet and lifestyle have influenced these anatomical features.
Conduct an experiment to observe the effects of different types of food on jaw strength. Use items like raw vegetables, cooked vegetables, and processed snacks. Measure and record the effort required to chew each type of food. Discuss how this relates to the changes in jaw size and dental health over time.
Arrange an interview with a dentist or orthodontist to discuss the article’s findings. Prepare questions about the impact of diet on dental health, the prevalence of tooth crowding, and modern orthodontic solutions. Record the interview and share the insights with your class.
Straight teeth – teeth that are aligned in a straight and orderly manner – Having straight teeth not only enhances your smile, but also improves your overall oral health.
Fossil record – the collection of all known fossils and their placement in chronological order – The fossil record provides valuable insights into the evolution of various species over millions of years.
Wisdom teeth – the third molars that typically erupt in the late teens or early twenties – Many individuals experience discomfort and may require extraction of their wisdom teeth due to lack of space in the jaw.
Dental issues – problems or conditions that affect the teeth or oral health – Regular dental check-ups help detect and prevent dental issues such as cavities and gum disease.
Subsistence lifestyle – a way of living where individuals rely on obtaining basic necessities for survival – Some indigenous communities still follow a subsistence lifestyle, relying on hunting, fishing, and gathering for their sustenance.
Grinding – the act of rubbing or pressing two surfaces together, often with force – Teeth grinding, also known as bruxism, can lead to enamel erosion and other dental complications.
Crushing – applying pressure to break or compress something into smaller pieces – Large molars are adapted for crushing and grinding tough food items.
Pulverizing – reducing something to a fine powder or substance – The powerful jaws of some animals are capable of pulverizing bones for consumption.
Jawbone size – the physical dimensions and structure of the bone that forms the jaw – Jawbone size can influence the alignment and spacing of teeth.
Dental crowding – a condition where there is insufficient space in the jaw for all the teeth, resulting in overlapping or misaligned teeth – Orthodontic treatment is often required to correct dental crowding and achieve proper alignment.
Impacted wisdom teeth – wisdom teeth that are unable to fully emerge or grow properly – Impacted wisdom teeth can cause pain, infection, and damage to neighboring teeth, necessitating their removal.
