Unlocking Ancient Secrets: How Dental Plaque Reveals the History of Disease

Imagine peering into the past to understand the diseases that plagued our ancestors. While bones and mummies offer clues, a groundbreaking new tool is revolutionizing our understanding of ancient health: fossilized dental plaque, also known as dental calculus or tartar.

The Power of Evolutionary Medicine

Evolutionary medicine seeks to understand the origins and evolution of human health and disease. One approach involves extracting DNA from ancient bones to reconstruct the human genome at different points in time. This allows researchers to identify genetic changes related to adaptations, risk factors, and inherited diseases.

However, the most pressing health challenges today stem from the complex interplay of genetics, diet, microbes, parasites, and our immune response. To truly understand these diseases, we need a holistic approach that considers the environments in which our bodies evolved.

Overcoming the Challenges of Studying the Past

Studying ancient diseases presents several challenges:

Skeletons: While abundant, skeletons offer limited health information due to the decomposition of soft tissues.
Mummies: Mummies provide valuable insights but are geographically and temporally limited.
Coprolites (fossilized feces): These can reveal information about ancient diet and intestinal disease but are rare.

To overcome these limitations, researchers have turned to a surprisingly common and informative source: dental calculus.

Dental Calculus: A Window into the Past

Dental calculus is fossilized dental plaque that accumulates on teeth. Unlike other sources of ancient DNA, dental calculus offers several advantages:

Abundance: It is found in large quantities, especially in pre-toothbrushing eras.
Ubiquity: It is present in populations worldwide and across various time periods, including Neanderthals and animals.
Fossilization: It fossilizes like the rest of the skeleton, preserving valuable information.

What Can Dental Calculus Tell Us?

Previous studies using microscopy revealed pollen, plant starches, and muscle cells in dental calculus. However, recent advancements in genetic and proteomic technologies have unlocked even greater potential.

By analyzing the DNA and proteins within dental calculus, researchers can identify:

Commensal and pathogenic bacteria: These reveal insights into the microorganisms that inhabited the mouth and nasal passages.
Immune proteins: These provide evidence of past infections and inflammatory responses.
Dietary information: DNA and proteins related to diet offer clues about ancient eating habits.

Gaining Virtual Access to the Body

Remarkably, dental calculus can even provide access to parts of the body that are otherwise inaccessible in skeletal remains. Researchers have found bacteria that typically inhabit the:

Upper respiratory system: Offering a glimpse into the lungs and respiratory diseases.
Gut: Providing insights into the digestive system, which decomposes long before the skeleton is studied.

Reconstructing the Past, Informing the Future

By applying advanced DNA sequencing and protein mass spectrometry to ancient dental calculus, researchers are generating vast amounts of data. This data is used to reconstruct a detailed picture of the dynamic interplay between diet, infection, and immunity thousands of years ago.

This research allows us to investigate the long-term evolutionary history of human health and disease, right down to the genetic code of individual pathogens. By understanding how pathogens evolve and why they continue to make us sick, we can better manage our health in the future.

So, the next time you brush your teeth, remember the wealth of information that dental plaque holds about our past. While maintaining good oral hygiene is essential, consider the potential value of this often-overlooked substance for future archaeological discoveries.

Tags: Archaeology, Genetics, Disease History