• September 26, 2018
What Ancient Teeth Can Tell Us About Humanity's Past

Some people who view ancient human remains, may just see the body in front of them. Anthropologists tend to see someone’s family member or perhaps someone who had an impact in their community. In other words, they see the life once lived by that person, beyond the physical remnants.

Historically, anthropology has depended on studying ancient teeth, as well as bones, to date human remains and lend a cultural context to the findings.

Teeth are great for studying our past for a few reasons.

First, teeth tend to be plentiful in archaeological sites because they are stronger than bone; therefore they can outlast other remains, according to anthropologist Peter Ungar in Evolution’s Bite: A Story of Teeth, Diet, and Human Origins.

Secondly, teeth can provide many insights into the genetic traits of individuals or even whole populations who are long gone. “With modern, non-destructive dental anthropological methods, we’re contributing to an improved understanding of ancestral heritage, and helping the scientific community improve cultural sensitivity,” says Dr. Michael D. Colvard, professor of oral medicine and diagnostic sciences and director of the Dental Medicine Responder Training Office at the UIC College of Dentistry.

Dr. Colvard is a dental anthropologist and a dental forensics specialist, which means he studies teeth and their parts in non-living human remains, as part of his teaching and research.

Since 1999, Dr. Colvard has been conducting studies into the benefits and drawbacks of plants used in various applications in dentistry through the ages.

For his PhD work, Dr. Colvard studied dental treatments used during the Middle Ages in Europe. “My focus was on the plants used by the Knights Hospitaliers, and how the clergy, monks, and knights attempted to treat dental and oral pain and provide analgesia during traumas and epidemics of the Middle Ages.”

During those dark times of limited medical knowledge, “the clergy and knights used wine as a topical antibiotic, and they would use marijuana, and poppy for pain and trauma,” he added.

 

Studying Ancient Teeth Opens a Window Into Our Past

While teeth share a common genetic code at the genus level, they also provide anatomical clues to understand differences in human behaviors over ancient times. So, we can analyze teeth to inform overall human ancestry and gender. For instance, when looking at Asian human remains, the teeth show differences from their Caucasian counterparts.  Also, the gender of ancient human remains can be determined because women have somewhat differently shaped teeth than men do. Regional ancestry can be determined by examining the teeth pump based on a genetic simulation. And more specifically, the specimen’s dietary patterns can be estimated based on the teeth condition. For example, a spectroscopic analysis of dental calculus (plaque) can lend clues to ancient dietary habits – and even how they treated medical ailments - based on the ancient foods and medicinal product DNA still contained within it. Also, a range of lifespan may be determined using traditional anthropological methods.

The nerve inside our teeth is protected, so it becomes a reliable source of archived genetic information for studying the past, and current events, even if the rest of the body is largely damaged. The DNA stored in our teeth nerve can be a door to our past culture, as well as current identity, for those who have the key. Dental anthropologists like Dr. Colvard not only have the key, they know how to make use of what’s beyond the doors to our past.

Anthropologists have extracted genetic information from teeth in humans that lived as many as 20 thousand years ago. So, from the Egyptian pharaohs, all the way back to the first humans who migrated to the Americas during the last Ice Age about 10 to 12 thousand years ago, we can learn about them from studying their teeth.

 

Using Today’s Technology to Study the Past

Researchers in the College of Dentistry incorporate the use of advanced diagnostic imaging technology to contribute to these genetic analysis efforts.

For instance, Dr. Colvard is leading CT analysis on human specimens in the Thompson Collection at the Field Museum in Chicago. “We’re currently studying Meso American Indian specimens who lived in Central and South America thousands of years ago, explains Dr. Colvard. The team is using CT imaging to study ancient dental implants placed by the Indians who once lived in modern day Costa Rica. They have discovered that indeginous pre-Mayan tribesmen of that area would implant tiny pieces of Jade stone into their patients’ teeth, to either repair tooth decay, or for status-based decoration.

“The next step for us is to better understand why they inserted Jade into the teeth. We think it was either for dental care, beauty, religion or status-based reasons,” explains Colvard. Knowing this may help the scientific team better date when these people lived, which in turn helps inform their cultural context. Dating these specimens has proven difficult because past efforts were sometimes destructive, and didn’t benefit from the cultural and religious sensitivities we now appreciate today.

 

Studying Ancient Tooth Repair in Central America

Costa Rica – the tourist paradise of rain forests and amazing wild life, is also home to an entire community of indigenous people. More than 63,000 indigenous ( 1.7% of the country’s population) still inhabit ancient lands passed down by their ancestors long before 1502 when Christopher Columbus came ashore there. In recent field studies in Costa Rica, UIC researchers now know that Ngabe Indians were practicing a primitive form of dentistry. 

“We have good records from the Spanish clergy writings of the time that tell us about dental care hundreds of years ago in Central America,”says Colvard. If you had a cavity in 1500 Costa Rica, doctors of the time –called shamans - would likely use a primitive drilling device called a bow drill made from a stick and cord that would turn a stone bit into the teeth. “They used what they had around them at the time - stones, wood and other natural materials – to treat tooth decay the best way they knew how,” adds Dr. Colvard. “They then invented technology to make better use of the materials they had around them. In a way, we owe the modern high speed hand drill to these early innovations.”

They also managed pain (from the decayed tooth, and from the primitive treatment) using plant-based medicines. Once this very painful step was complete, the dentist would insert a stone, such as Jade, to fill the cavity. We also have seen examples of teeth shapes being made, such as being carved into a point.

The practice of extracting medicinal benefits from plants was eventually exported from the Central and South Americas into Europe, as some of the early forerunners to today’s medicine. For instance, the numbing agent lidocaine, one of the world’s most essential medicines, is derived from cocaine, which is manufactured from the coca leaf, which has been cultivated for centuries in Central and South America.

Another example is nicotine, which is derived from tobacco plants originated in the Americas, and is named after Nico, an early French Ambassador to Portugal.

The Importance of Teaching Dental Anthropology

Those who don’t study history are bound to repeat it. We study the past in order to understand, mitigate and prevent in ways to benefit the greater good. Having a firm understanding of how our ancestors both benefited from – and  may have been harmed by – ancient practices of medicines and treatments, is essential to being a good student, practitioner and scientist in modern medicine. The past truly informs how we should more effectively treat disease today and into the future.

Particularly in the area periodontal care, we can improve on non-invasive therapies such as deep cleaning (scaling and root planing) and advanced surgery procedures such as pocket reduction, grafting, crown lengthening, and regenerative procedures to better manage periodontal and implant disease.

The future of dentistry stands to benefit greatly from understanding out past. For instance, future regenerative therapies to restore and save teeth can benefit from understanding how past therapies failed, and eventually evolved into today’s advances in the oral sciences.

 

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