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Chapter 5: From Chew Sticks to Chlorhexidine

In which we trace the history of oral care from Babylonian twigs to modern antiseptic mouthwash, and discover that progress isn't always linear

The first toothbrush was a stick.

Not a specially designed stick. Not a manufactured product. Just a twig—probably from an aromatic tree—that someone in ancient Babylon, around 3500 BCE,1 decided to chew on until the fibers frayed into something brush-like. They rubbed this frayed end against their teeth, and something good happened. The practice spread.

This wasn't superstition. It wasn't ritual (though it would become ritualized in many cultures). It was practical problem-solving, refined through generations of trial and error. The ancients noticed that certain chewing sticks worked better than others. They noticed that some plants left their mouths feeling fresher, their gums less inflamed. They didn't know about antimicrobial compounds or mechanical plaque removal, but they were doing both.

I've watched humans throughout this long journey, and what strikes me most is how much they knew before they knew why they knew it.

The Ancient Wisdom

The Tooth Fairy examining miswak sticks in an ancient marketplace.

The earliest recorded oral hygiene practices come from Babylonian texts around 3500 BCE. The Babylonians used chewing sticks called "miswak" or "siwak"—the same practice that continues today in much of the Middle East and Africa, using twigs from the Salvadora persica tree.

The ancient Egyptians (around 5000 BCE) developed a tooth powder made from myrrh, powdered ox hoof, pumice, burned eggshells, and ashes.2 Abrasive, yes, but functional. They also used chewing sticks and are credited with the earliest known reference to a dental practitioner: Hesy-Ra, described as "the greatest of those who deal with teeth."

Ancient China developed sophisticated tooth-cleaning practices by 1600 BCE, including chewing sticks and tooth powders. By the 15th century CE, Chinese inventors had created what might be considered the first bristle toothbrush—boar bristles set into a bamboo handle.3 This design would eventually travel to Europe and become the basis for the modern toothbrush.

The Greeks theorized extensively about teeth and oral health. Hippocrates (460-370 BCE) wrote about tooth decay and extraction techniques. Aristotle discussed the gums, the different types of teeth, and even speculated about why some teeth came in late.

The Romans inherited Greek knowledge and added their own innovations. They used various tooth powders containing crushed bones, oyster shells, and bark. Celsus (25 BCE-50 CE) wrote about oral hygiene practices and treatment of tooth diseases. The Romans also used urine as a mouthwash—both human and imported Portuguese urine, which was apparently considered superior. The ammonia in urine actually does have antimicrobial properties, so this wasn't as crazy as it sounds.

Ayurvedic medicine in India prescribed tongue cleaning (jihwa prakshalana) as part of morning hygiene rituals thousands of years ago—a practice now validated by modern research for halitosis control.

What all these ancient traditions shared was an ecological intuition. They weren't trying to sterilize the mouth. They were trying to maintain it—removing accumulated debris, freshening breath, soothing inflammation. The herbs and plants they used often had genuine antimicrobial properties, but at concentrations and contact times that would have modified the oral environment rather than devastated it.

Then came the Middle Ages, and things got worse before they got better.

The Dark Age of Dentistry

In medieval Europe, dental care devolved. The sophisticated knowledge of the Greeks and Romans was largely lost or ignored. Tooth extraction—usually without anesthesia—became the primary treatment for dental problems. The practitioners were often barber-surgeons, whose primary trade was cutting hair but who also performed surgeries, bloodletting, and tooth-pulling.

The barber pole, with its red and white stripes, originally represented bloody bandages hanging to dry.

Tooth decay was attributed to "tooth worms"—invisible creatures that burrowed into teeth and caused pain. This theory, probably originating in Mesopotamia, persisted for centuries. Treatments aimed at killing or driving out the worms, often involving heated instruments applied to cavities.

Some folk remedies from this period were genuinely harmful. Others were surprisingly sensible—sage leaves for gum inflammation, clove oil for pain. The problem wasn't the absence of useful knowledge; it was the absence of any framework for distinguishing useful knowledge from nonsense.

The Emergence of Modern Dentistry

Pierre Fauchard, a French physician working in the early 18th century, is often called the "Father of Modern Dentistry."4 His 1728 book, Le Chirurgien Dentiste ("The Surgeon Dentist"), was the first comprehensive scientific description of dentistry as a profession.

Fauchard debunked the tooth worm theory, described the relationship between sugar and decay, introduced the concept of dental fillings, and designed numerous dental instruments. He also recommended regular cleaning of teeth and criticized the harsh abrasives commonly used at the time.

From this point forward, dentistry gradually professionalized. Dental schools were established (the first in America in 1840), licensure requirements were developed, and the systematic study of oral disease began.

But the transformation that would most shape modern oral health thinking came not from dentistry itself but from microbiology.

The Germ Theory Revolution

In the 1850s and 1860s, Louis Pasteur demonstrated that fermentation and putrefaction were caused by microorganisms. Robert Koch subsequently established that specific bacteria caused specific diseases. The germ theory of disease was born.

The implications revolutionized medicine. If diseases were caused by specific microorganisms, they could be treated by eliminating those organisms. Antiseptic surgery, developed by Joseph Lister using carbolic acid, dramatically reduced post-surgical infections. Antibiotics, beginning with penicillin in the 1940s, transformed the treatment of bacterial infections.

For dentistry, the germ theory prompted research into the bacterial causes of tooth decay and gum disease. Willoughby D. Miller, an American dentist working in Germany in the 1880s, proposed the "chemico-parasitic theory" of caries:5 bacteria in the mouth fermented carbohydrates to produce acids that dissolved tooth enamel.

Miller was largely correct. His work was foundational. But his framing—bacteria as parasites, decay as an infection to be eliminated—set the stage for approaches that would focus on bacterial destruction rather than ecological management.

G.V. Black, another giant of dental research around the turn of the 20th century, developed the principles of cavity preparation and filling that remained standard for nearly a century. His approach was mechanical: remove all decayed tissue, extend the cavity preparation into areas likely to decay in the future, and restore with amalgam. "Extension for prevention" was the motto.

Black's techniques saved countless teeth. But they were fundamentally reactive—dealing with damage after it occurred rather than preventing the conditions that caused it.

The Rise of Antiseptics

Given the germ theory framework, the development of antiseptic mouthwashes was almost inevitable.

Listerine was invented in 1879, originally as a surgical antiseptic.6 It was named after Joseph Lister, the pioneer of antiseptic surgery. Its formula—containing thymol, eucalyptol, methyl salicylate, and menthol in a 26.9% alcohol solution—was designed to kill bacteria through multiple mechanisms: the alcohol disrupted cell membranes, while the phenolic compounds provided additional antimicrobial action.

By the 1920s, Listerine was being marketed for bad breath (which the company helped popularize as a social catastrophe), and the antiseptic mouthwash was established as a consumer product.

Chlorhexidine, developed in the 1950s,7 represented the next step in antiseptic technology. It binds to oral tissues and releases slowly over time, providing sustained antimicrobial activity. Clinical trials showed dramatic reductions in plaque and gingivitis. For many dental professionals, chlorhexidine became the gold standard—the most effective antimicrobial agent available for oral use.

Cetylpyridinium chloride (CPC) emerged as a less potent but more palatable antiseptic, finding its way into numerous over-the-counter mouthwashes.

By the late 20th century, the antiseptic approach to oral health was firmly entrenched. The logic seemed unassailable: bacteria cause decay and gum disease; antiseptics kill bacteria; therefore, antiseptics prevent oral disease.

But the logic rested on an assumption that was beginning to crack.

The Ecological Turn

As microbiome research exploded in the 2000s and 2010s, the simplicity of the "kill all germs" approach became increasingly difficult to defend.

Researchers discovered that the oral microbiome wasn't just a collection of potential pathogens waiting to cause trouble. It was a complex ecosystem with many beneficial functions. Some bacteria produced alkali to neutralize acid. Some outcompeted pathogens. Some contributed to systemic health through pathways like nitrate reduction.

Studies began to document the collateral damage of antiseptic approaches:

  • Chlorhexidine, despite its efficacy against plaque, caused tooth staining and taste disturbance
  • Long-term antiseptic use was associated with altered oral microbiome composition that didn't necessarily favor health
  • The blood pressure connection emerged: antiseptic mouthwash users showed elevated systolic blood pressure
  • Antibiotic resistance, already a concern elsewhere in medicine, was found in oral bacteria

Most fundamentally, the ecological research showed that you couldn't eliminate S. mutans and expect the problem to be solved. S. mutans became dominant because of environmental conditions—frequent sugar exposure creating repeated acid stress. Change the conditions, and a different community would emerge. Kill the bacteria without changing the conditions, and the same community would return.

This didn't mean that antiseptics were useless. For specific therapeutic situations—active periodontal infection, post-surgical care, high-risk patients—they had clear value. But as daily maintenance for healthy individuals? The evidence was increasingly unclear.

The pendulum began to swing.

Where We Are Now

We're in a transitional moment in oral health thinking. The antiseptic paradigm hasn't been abandoned—pharmacy shelves are still full of mouthwashes promising to kill 99.9% of germs. But within dental research, the ecological perspective has become mainstream.

The concept of oral homeostasis—maintaining a healthy equilibrium rather than pursuing sterility—now guides much research. Probiotics, prebiotics, targeted interventions that spare beneficial species—these are active areas of investigation.

The arginine-containing toothpastes that feed alkali-producing bacteria represent a practical application of ecological thinking. So does the research into selective anti-caries agents that might target S. mutans specifically while leaving other species intact.

We're also seeing renewed interest in traditional remedies—not as replacements for scientific dentistry, but as sources of compounds and approaches that might have ecological wisdom embedded in them. The miswak, dismissed for decades as a primitive alternative to the modern toothbrush, is now recognized by the WHO as an effective oral hygiene tool,8 and research has identified specific bioactive compounds that contribute to its efficacy.

The history I've recounted isn't a story of progress replaced by regression. It's a story of incomplete understanding being completed. The germ theory was correct but partial. The antimicrobial approach was effective but blunt. What we're developing now—ecological management, informed by both modern microbiology and traditional practice—is more nuanced, more sophisticated, and ultimately more aligned with how mouths actually work.

Your teeth evolved in the context of a bacterial ecosystem. They need that ecosystem—properly balanced—to thrive. The ancestors who chewed miswak twigs and rinsed with sage understood this intuitively. The scientists who developed chlorhexidine forgot it temporarily. The researchers of today are remembering.

But what, exactly, is wrong with the scorched-earth approach? Let's examine the evidence for harm in more detail.

  1. History of dental treatments — Wikipedia. Evidence of chewing sticks dates back to approximately 3500 BCE in Babylonia. ↩

  2. Forshaw, R. J. (2009). The practice of dentistry in ancient Egypt. British Dental Journal, 206(9), 481-486. ↩

  3. Toothbrush — Wikipedia. The first bristle toothbrush was invented in China during the Tang Dynasty (619–907) and was made of hog bristles. ↩

  4. Pierre Fauchard — Wikipedia. Often called "the father of modern dentistry" for his comprehensive 1728 work on dentistry. ↩

  5. Miller, W. D. (1890). The Micro-organisms of the Human Mouth. Philadelphia: S.S. White. The foundational text describing the chemico-parasitic theory of dental caries. ↩

  6. Listerine — Wikipedia. Developed in 1879 by Joseph Lawrence and Jordan Wheat Lambert as a surgical antiseptic. ↩

  7. Chlorhexidine — Wikipedia. Developed in the 1950s at Imperial Chemical Industries. ↩

  8. World Health Organization. (1987). Prevention of oral diseases. Geneva: WHO. The WHO recognized miswak as an effective tool for oral hygiene. ↩