The “Hidden Epidemic”: The Danger of Silent Oral Infections

Most people think an oral infection should hurt. But in dentistry, some infections can be surprisingly quiet—especially when they’re deeper around the roots of teeth or in the supporting bone. Absence of pain doesn’t always mean absence of a problem.

This article draws from Hidden Epidemic by Dr. Thomas E. Levy.¹ While not an exhaustive summary by any means, it shares several of the book’s points about asymptomatic oral infections: (1) how common oral infections may actually be, (2) how oral infection/inflammation may relate to chronic disease, and (3) why root canal–treated teeth may put a person at significantly higher risk for oral infection.¹

Please note: some of Levy’s conclusions go beyond mainstream consensus.² ³ We’ll present both perspectives so you can draw your own conclusions and bring questions to your dental consultation.² 

Table of Contents

1. Just How Common Is Oral Infection?
2. Are Root Canals Linked to Oral Infection?
3. Why Oral Infection Matters: Links to Degenerative Disease
4. How to Identify Possible Oral Infection
5. How Dental Implants Can Treat Oral Infection
6. Sources

Just How Common Is Oral Infection?

It is widely accepted that gum disease is common in adults. In U.S. adults age 30+ with natural teeth, mainstream estimates say that about 42.2% have periodontitis (with ~7.8% having severe periodontitis).⁴ 

However, Dr. Levy argues the problem extends beyond visible gum inflammation to include a wide range of chronic, often painless oral infections—around teeth, in the jawbone, and in related areas of the mouth/throat.¹ In particular, he emphasizes chronic apical periodontitis (CAP), an infection/inflammation around the tip of a tooth root that may be discovered only with dental imaging and can exist without symptoms.¹ ⁵

In particular, Dr. Levy cites root canals as a major risk factor for oral infection.

Are Root Canals Linked to Oral Infection?

Root canal treatment is a standard procedure intended to treat infection inside a tooth and help save the tooth.¹⁵ ¹⁶ It is widely accepted that outcomes can vary with root canals, and some teeth can develop persistent or recurrent infection, cracks, or structural issues over time—sometimes requiring retreatment or extraction depending on the case.¹⁵ 

However, Levy argues that persistent infection in root canal–treated teeth is far more common than generally acknowledged.¹ In fact, he argues that root canals always lead to oral infection. His support for this argument is a study in which “100% of the 5,000 examined root canal–treated teeth were infected,” cited initially in The Toxic Tooth (Kulacz & Levy).⁶ He also draws on cardiovascular microbiology and epidemiology papers to argue that oral pathogens (including those associated with endodontically treated teeth and periodontal disease) may be directly involved in coronary disease and even acute events in some patients.¹ ⁸ ⁹ ¹⁰

Why patients should care: Whether you approach this from a mainstream periodontal perspective or Levy’s broader “focal infection” model, both agree on a practical point: oral disease can be easy to underestimate when symptoms are mild or absent.¹ ² 

If you have a tooth with prior root canal treatment and you’re dealing with recurring symptoms, recurring gum “pimples,” swelling, tenderness on biting, or unexplained inflammation, it’s reasonable to ask your dentist what signs of persistent infection they look for and what diagnostic steps make sense for your situation.

Why Oral Infection Matters: Links to Degenerative Disease

Many studies report associations between periodontal disease and systemic conditions—especially cardiometabolic conditions—and leading organizations recognize an oral-systemic relationship mediated in part by inflammation and, at times, bacteria entering the bloodstream.² ³ Mainstream sources are typically cautious about declaring direct cause-and-effect for broad claims across many diseases, because association can reflect shared risk factors (smoking, diabetes, socioeconomic factors, access to care) and complex biology.³ 

Levy interprets this literature more strongly, arguing that chronic oral infections are frequently a major driver of degenerative disease and not merely “associated.”¹ His book emphasizes links between oral infection and:

Cardiovascular disease/heart attacks

Levy cites numerous studies documenting connections between periodontal disease and heart disease.¹ ⁹ ¹⁰

In particular, he references a study showing that in 78% of 101 patients presenting with myocardial infarctions, the DNA of the pathogens typical for infections in root-canal-treated teeth were found in their blood clots. Additionally, the same study showed that the concentration of the pathogen DNA in the blood clots was 16 times higher than in surrounding arterial blood.¹⁷ Levy believes that this is a “smoking gun” study that shows that “root canal-related teeth are the direct cause for the vast majority of heart attacks”.

Cancer risk (multiple sites)

In his book, Levy discusses the link between oral infection and a wide variety of cancers, with some studies showing as much as a 2.5–4-fold increase in some cancers in people with advanced periodontitis.¹¹ ¹²

One of these was breast cancer, due to a study that showed periodontal pathogens like Fusobacterium to be “significantly enriched in breast tissue from women with malignant disease”.¹⁸ Levy notes that the same periodontal pathogens are also linked to colon cancer by other scientific studies.¹⁹

He also mentions two large studies—one with 50,000 subjects and another with 200,000 subjects—that both found links between periodontitis and pancreatic cancer, as well as another large study of over 320,000 subjects showing a link to lung cancer.²⁰ ²¹

Neurological disease (including Alzheimer’s disease)

According to Levy, periodontal pathogens also have connections to neurological diseases such as Alzheimer’s, and may even contribute to increased cognitive decline in this disease.²² They can also contribute to Parkinson’s disease, although Levy notes that periodontitis is one of multiple infections that can contribute here.²³

Additionally, Levy notes a positive correlation between periodontal disease and seizures, as well as an unusual link to depression, with the latter apparently increasing risk for periodontitis just as periodontitis can cause depression.²⁴

Broader “multi-system” impacts

Levy argues that oral infection can contribute to a disturbingly high variety of additional diseases and conditions, pointing to scientific literature for each condition that establishes this link. The conditions shared by Levy include:

• Arthritis.²⁵
• Diabetes.²⁶
• Osteoporosis.²⁷
• Inflammatory bowel disease.²⁸
• Chronic kidney disease.²⁹
• Sudden hearing loss.³⁰
• Erectile dysfunction.³¹

What this means for patients: A conservative interpretation is that reducing chronic oral inflammation and treating known oral infections is part of good whole-body health management—especially for patients with diabetes or cardiovascular risk.² ³

Levy’s interpretation is more ambitious: he argues that identifying and eliminating silent oral infections could meaningfully shift the trajectory of many chronic diseases.¹ 

Regardless, risk of oral infection should be taken seriously, as it contributes to health risks throughout the body.

How to Identify Possible Oral Infection

Even when teeth and gums look or feel “normal,” deeper infection can still be present. Below are tools dentists may use—ranging from imaging to blood work—to look for hidden sources of inflammation or infection in and around the mouth.

I) Advanced Dental Imaging
Many biologically oriented and endodontic practices now use 3D cone beam CT (CBCT) scans to evaluate the teeth, jawbone, and surrounding structures in three dimensions.¹ CBCT can reveal changes around tooth roots (such as chronic apical periodontitis), areas of bone loss, cyst-like lesions, or other abnormalities that may not show on traditional 2‑D X‑rays, especially when lesions are small or located between roots.¹

By contrast, standard dental X‑rays show only a single angle at a time and can miss early or subtle changes, particularly behind overlapping structures. CBCT also allows more precise planning if treatment is needed (for example, retreating a root canal or extracting a tooth) and can be interpreted by a licensed dentist, endodontist, oral surgeon, or other trained specialist during a comprehensive exam.

II) Clinical Exam and Symptom Review

Imaging is paired with a hands‑on clinical exam. Even if you feel fine, your dentist may look for:

• Local signs: gum swelling, sinus tracts (“pimples” on the gum), redness, tenderness on biting or tapping, looseness of a tooth, or changes in the bite.¹
• History clues: prior root canals, large fillings, crowns, trauma to teeth, or teeth that have been sensitive “on and off” for years.¹
• Systemic clues: unexplained fatigue, low‑grade fevers, or chronic inflammatory conditions that flare without obvious triggers (these are non‑specific but may prompt a closer look at the mouth in Levy’s model).¹

From a mainstream perspective, many of these findings simply support a diagnosis of localized dental disease (like an abscess or periodontitis) that should be treated to protect the tooth and surrounding bone.² Levy’s view is that even low‑grade or “quiet” infections around roots can be medically relevant far beyond the mouth, particularly for patients already dealing with cardiovascular or other chronic disease.¹

III) Baseline Laboratory Testing

Levy places strong emphasis on using blood tests to track overall inflammatory burden, arguing that some silent oral infections may show up as a persistent, unexplained elevation in inflammatory markers or other lab abnormalities.¹ In addition to routine dental diagnostics, he suggests discussing with your physician whether it makes sense to obtain:

• A complete blood count (CBC) and standard biochemistry panel.¹
• Lipoprotein testing and other cardiovascular risk markers.¹
• Autoimmune screening tests such as ANA and rheumatoid factor (RF), when clinically appropriate.¹
• Thyroid panel and sex hormone levels.¹
• Markers related to chronic inflammation (for example, commonly used tests in medical practice include C‑reactive protein and erythrocyte sedimentation rate, though individual panels vary by lab and clinician).¹ ³
• Iron status (including ferritin) and vitamin D levels.¹

Mainstream organizations agree that chronic periodontal disease contributes to systemic inflammatory load and that some patients with heart disease or diabetes may particularly benefit from good periodontal management, but they do not routinely recommend broad lab panels solely to screen for dental infections.² ³ Levy’s approach is more inclusive: he views changes in these labs, in the right clinical context, as possible clues to hidden oral infection that warrant further dental investigation.¹

IV) Cardiovascular and Other Imaging When Indicated

Because Levy sees oral infection as a frequent driver of cardiovascular disease, he highlights testing such as coronary artery CT scans or other cardiovascular evaluations as part of a broader systemic work‑up when risk factors or symptoms are present.¹ In this framework, dental findings (for example, multiple root canal‑treated teeth with radiographic signs of chronic infection) and cardiovascular findings (for example, evidence of atherosclerosis on imaging) may be considered together when deciding how more comprehensively to look for and treat “silent” oral sources.¹ ⁹ ¹⁰

Mainstream cardiology and dental guidelines do not currently recommend routine coronary CT specifically to hunt for dental‑origin infections.³ Instead, coronary imaging is usually ordered based on standard risk stratification and symptoms, with oral health addressed through regular dental care and management of established periodontal disease.² ³

How Dental Implants Can Treat Oral Infection

Given that infected teeth are the cause of the vast majority of acute infections in the mouth, head, and neck regions, the most sustainable and comprehensive solution for treating oral infection is often removal and replacement of those infected teeth with dental implants.

A dental implant acts as the root of the replaced tooth, stimulating the bone and the gums. Without this stimulation, the bone and gum tissue recedes over time at a faster rate. Meanwhile, the firm anchor allows a replacement prosthetic (like a zirconia crown or bridge) to function like a natural tooth, allowing you to chew the same variety of foods and smile with confidence.

At The Dental Implant Place, the majority of dental implant cases we see are due to long-term tooth decay from oral infection. Fortunately, we are usually able to provide dental implants even in cases of significant bone loss, thanks to our minimally invasive approach, which minimizes surgical trauma and reduces discomfort.

We have placed over 14,000 dental implants over the last two decades using this minimally invasive approach, and many of our patients have reported that they are able to eat within days of their same-day dental implants treatment. Some have even reported feeling no pain during or after their surgery.

If you are interested in how dental implants could help you and would like to schedule a free in-person consultation, follow the link below and reach out to our office in Fort Worth, TX, and our team will get you scheduled.

Sources 

1. Levy, T.E. Hidden Epidemic: Silent Oral Infections Cause Most Heart Attacks and Breast Cancers. (Book; no link provided.)
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4. National Institute of Dental and Craniofacial Research (NIDCR). “Periodontal Disease in Adults (Age 30 or Older).” https://www.nidcr.nih.gov/research/data-statistics/periodontal-disease/adults[nidcr.nih]​
   
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